Merge branch 'develop' into techdebt/5708-meta-cleanup

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.github/workflows/cancel_closed_pr_runs.yml

@@ -0,0 +1,53 @@
+name: "Cancel runs of closed pull requests"
+
+# The concurrency groups of the other workflows cancel superseded runs when a
+# pull request gets new commits, but nothing stops the runs of its last commit
+# once the pull request is merged or closed. They then keep the runners busy
+# for hours while the queue of the open pull requests waits.
+#
+# pull_request_target is needed to get a token that can cancel runs for pull
+# requests from forks. This is safe because the workflow never checks out or
+# runs code from the pull request; it only calls the API.
+on:
+  pull_request_target:
+    types: [closed]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  cancel:
+    permissions:
+      actions: write
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Harden Runner
+        uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
+        with:
+          egress-policy: audit
+
+      - name: Cancel unfinished runs of the pull request's head commit
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          GH_REPO: ${{ github.repository }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
+          SELF: ${{ github.run_id }}
+        # only runs triggered by the pull request: when a branch is pushed to
+        # develop directly, its push runs share the head commit
+        run: |
+          gh api --paginate "repos/$GH_REPO/actions/runs?head_sha=$HEAD_SHA&per_page=100" \
+            --jq ".workflow_runs[]
+                  | select(.status != \"completed\" and .id != $SELF)
+                  | select(.event == \"pull_request\" or .event == \"pull_request_target\")
+                  | \"\(.id) \(.name)\"" |
+          while read -r id name; do
+            echo "Cancelling run $id ($name)"
+            # a run may finish between listing and cancelling; that is not an error
+            gh run cancel "$id" || true
+          done

.github/workflows/check_amalgamation.yml

@@ -2,16 +2,23 @@ name: "Check amalgamation"
 
 on:
   pull_request:
+  # also check develop itself: a PR can be merged before its own run of this
+  # workflow completes (e.g. while it is still queued), leaving single_include
+  # stale on develop without any failing check
+  push:
+    branches:
+      - develop
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
-  cancel-in-progress: true
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 permissions:
   contents: read
 
 jobs:
   save:
+    if: github.event_name == 'pull_request'
     runs-on: ubuntu-latest
     steps:
       - name: Harden Runner
@@ -43,11 +50,11 @@ jobs:
         with:
           egress-policy: audit
 
-      - name: Checkout pull request
+      - name: Checkout pull request or pushed commit
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           path: main
-          ref: ${{ github.event.pull_request.head.sha }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
           persist-credentials: false
 
       - name: Checkout tools

.github/workflows/comment_check_amalgamation.yml

@@ -10,7 +10,8 @@ permissions:
 
 jobs:
   comment:
-    if: ${{ github.event.workflow_run.conclusion == 'failure' }}
+    # push runs on develop have no PR to comment on (and no "pr" artifact)
+    if: ${{ github.event.workflow_run.conclusion == 'failure' && github.event.workflow_run.event == 'pull_request' }}
     runs-on: ubuntu-latest
     permissions:
       contents: read

BUILD.bazel

@@ -53,7 +53,6 @@ cc_library(
         "include/nlohmann/detail/meta/detected.hpp",
         "include/nlohmann/detail/meta/identity_tag.hpp",
         "include/nlohmann/detail/meta/is_sax.hpp",
-        "include/nlohmann/detail/meta/logic.hpp",
         "include/nlohmann/detail/meta/std_fs.hpp",
         "include/nlohmann/detail/meta/type_traits.hpp",
         "include/nlohmann/detail/meta/void_t.hpp",

CMakeLists.txt

@@ -61,7 +61,6 @@ option(JSON_Install                        "Install CMake targets during install
 option(JSON_MultipleHeaders                "Use non-amalgamated version of the library." ON)
 option(JSON_SystemInclude                  "Include as system headers (skip for clang-tidy)." OFF)
 option(JSON_StrictNulHandling              "Build with strict NUL-byte handling enabled." OFF)
-option(JSON_StrictBinaryUTF8               "Build with UTF-8 checks in the CBOR, UBJSON, BJData, and BSON writers enabled." OFF)
 
 if (JSON_CI)
     include(ci)
@@ -119,10 +118,6 @@ if (JSON_StrictNulHandling)
     message(STATUS "Strict NUL-byte handling enabled (JSON_STRICT_NUL_HANDLING=1)")
 endif()
 
-if (JSON_StrictBinaryUTF8)
-    message(STATUS "Strict UTF-8 checks in binary writers enabled (JSON_STRICT_BINARY_UTF8=1)")
-endif()
-
 if (JSON_Diagnostic_Positions)
     message(STATUS "Diagnostic positions enabled (JSON_DIAGNOSTIC_POSITIONS=1)")
 endif()
@@ -158,7 +153,6 @@ target_compile_definitions(
     $<$<BOOL:${JSON_Diagnostic_Positions}>:JSON_DIAGNOSTIC_POSITIONS=1>
     $<$<BOOL:${JSON_LegacyDiscardedValueComparison}>:JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON=1>
     $<$<BOOL:${JSON_StrictNulHandling}>:JSON_STRICT_NUL_HANDLING=1>
-    $<$<BOOL:${JSON_StrictBinaryUTF8}>:JSON_STRICT_BINARY_UTF8=1>
 )
 
 target_include_directories(

cmake/ci.cmake

@@ -691,7 +691,7 @@ ci_get_cmake(4.0.0  CMAKE_4_0_0_BINARY)
 # the tests require CMake 3.13 or later, so they are excluded for CMake 3.5.0
 set(JSON_CMAKE_FLAGS_3_5_0 JSON_Diagnostics JSON_Diagnostic_Positions JSON_GlobalUDLs JSON_ImplicitConversions JSON_DisableEnumSerialization
     JSON_LegacyDiscardedValueComparison JSON_Install JSON_MultipleHeaders JSON_SystemInclude JSON_Valgrind
-    JSON_StrictNulHandling JSON_StrictBinaryUTF8)
+    JSON_StrictNulHandling)
 set(JSON_CMAKE_FLAGS_3_31_6 JSON_BuildTests ${JSON_CMAKE_FLAGS_3_5_0})
 set(JSON_CMAKE_FLAGS_4_0_0 JSON_BuildTests ${JSON_CMAKE_FLAGS_3_5_0})
 

docs/mkdocs/docs/api/basic_json/dump.md

@@ -25,12 +25,10 @@ and `ensure_ascii` parameters.
     result consists of ASCII characters only.
 
 `error_handler` (in)
-:   how to react on decoding errors; there are four possible values (see [`error_handler_t`](error_handler_t.md):
+:   how to react on decoding errors; there are three possible values (see [`error_handler_t`](error_handler_t.md):
     `strict` (throws an exception in case a decoding error occurs; default), `replace` (replace invalid UTF-8 sequences
-    with U+FFFD), `ignore` (ignore invalid UTF-8 sequences during serialization; all valid bytes are copied to the
+    with U+FFFD), and `ignore` (ignore invalid UTF-8 sequences during serialization; all valid bytes are copied to the
-    output unchanged, and invalid bytes are dropped), and `keep` (write the ill-formed bytes to the output as is,
+    output unchanged, and invalid bytes are dropped)).
-    without escaping them, even if `ensure_ascii` is `#!cpp true`; the result is then not valid UTF-8, but equals the
-    input bytes exactly, and well-formed characters around the ill-formed bytes are still escaped as usual)).
     
 ## Return value
 
@@ -96,4 +94,3 @@ Binary values are serialized as an object containing two keys:
 - Indentation character `indent_char`, option `ensure_ascii` and exceptions added in version 3.0.0.
 - Error handlers added in version 3.4.0.
 - Serialization of binary values added in version 3.8.0.
-- Error handler `keep` added in version 3.13.0.

docs/mkdocs/docs/api/basic_json/error_handler_t.md

@@ -4,31 +4,15 @@
 enum class error_handler_t {
     strict,
     replace,
-    ignore,
+    ignore
-    keep
 };
 ```
 
-This enumeration is used to choose how to treat ill-formed UTF-8 in a string value or object key:
+This enumeration is used in the [`dump`](dump.md) function to choose how to treat decoding errors while serializing a
-
+`basic_json` value. Three values are differentiated:
-- [`dump`](dump.md) uses it while serializing a `basic_json` value to text.
-- [`to_cbor`](to_cbor.md), [`to_msgpack`](to_msgpack.md), [`to_ubjson`](to_ubjson.md), [`to_bjdata`](to_bjdata.md),
-  and [`to_bson`](to_bson.md) use it while serializing a `basic_json` value to that binary format. Their default is
-  `keep`, as no binary writer checked before this parameter was added. CBOR, UBJSON, BJData, and BSON require valid
-  UTF-8, so for these four the default is `strict` if [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md)
-  is enabled; MessagePack's specification explicitly allows a string to contain ill-formed UTF-8, so `to_msgpack`
-  stays at `keep`. `to_bon8` does not take this parameter: BON8 always validates, since UTF-8 lead bytes are
-  structural to that format.
-- [`from_cbor`](from_cbor.md), [`from_msgpack`](from_msgpack.md), [`from_ubjson`](from_ubjson.md),
-  [`from_bjdata`](from_bjdata.md), and [`from_bson`](from_bson.md) use it while parsing that binary format, to decide
-  whether to check a string value or object key for well-formed UTF-8 at all; by default (`keep`) they do not, as no
-  binary reader did before this parameter was added. `from_bon8` does not take this parameter, for the same reason
-  `to_bon8` does not.
-
-Four values are differentiated:
 
 strict
-:   throw a `type_error`/`parse_error` exception in case of invalid UTF-8
+:   throw a `type_error` exception in case of invalid UTF-8
 
 replace
 :   replace invalid UTF-8 sequences with U+FFFD (� REPLACEMENT CHARACTER)
@@ -36,12 +20,6 @@ replace
 ignore
 :   ignore invalid UTF-8 sequences; all valid bytes are copied to the output unchanged, and invalid bytes are dropped
 
-keep
-:   keep invalid UTF-8 sequences unchanged; only meaningful for the binary formats mentioned above, since [`dump`]
-    (dump.md) itself must produce text, and `keep` there writes the ill-formed bytes to the output as is, so the
-    result is then not valid UTF-8 (but still equals the input bytes exactly, including around any well-formed
-    characters, which are still escaped as usual)
-
 ## Examples
 
 ??? example
@@ -62,5 +40,3 @@ keep
 ## Version history
 
 - Added in version 3.4.0.
-- Added `keep`, and made this enumeration apply to the binary readers and writers in addition to `dump`, in version
-  3.13.0.

docs/mkdocs/docs/api/basic_json/from_bjdata.md

@@ -5,14 +5,12 @@
 template<typename InputType>
 static basic_json from_bjdata(InputType&& i,
                               const bool strict = true,
-                              const bool allow_exceptions = true,
+                              const bool allow_exceptions = true);
-                              const error_handler_t error_handler = error_handler_t::keep);
 // (2)
 template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_bjdata(IteratorType first, SentinelType last,
                               const bool strict = true,
-                              const bool allow_exceptions = true,
+                              const bool allow_exceptions = true);
-                              const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Deserializes a given input to a JSON value using the BJData (Binary JData) serialization format.
@@ -60,12 +58,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 `allow_exceptions` (in)
 :   whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
 
-`error_handler` (in)
-:   how to treat a string value or object key that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    BJData does not require a decoder to reject ill-formed UTF-8, so checking is opt-in: the default, `keep`, does not
-    check at all, as every binary reader did before this parameter was added; `strict` checks and throws;
-    `replace`/`ignore` sanitize the string the same way [`dump`](dump.md) would
-
 ## Return value
 
 deserialized JSON value; in case of a parse error and `allow_exceptions` set to `#!cpp false`, the return value will be
@@ -81,7 +73,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
   the end of the file was not reached when `strict` was set to true
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs
 - Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed
-  successfully, or if a string value or object key is not valid UTF-8 and `error_handler` is `strict`
+  successfully
 - Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the size of an optimized container
   or n-dimensional array cannot be represented by `std::size_t`
 
@@ -119,4 +111,3 @@ Linear in the size of the input.
 - Added in version 3.11.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
 - Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
-- Added `error_handler` parameter in version 3.13.0.

docs/mkdocs/docs/api/basic_json/from_bson.md

@@ -5,14 +5,12 @@
 template<typename InputType>
 static basic_json from_bson(InputType&& i,
                             const bool strict = true,
-                            const bool allow_exceptions = true,
+                            const bool allow_exceptions = true);
-                            const error_handler_t error_handler = error_handler_t::keep);
 // (2)
 template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_bson(IteratorType first, SentinelType last,
                             const bool strict = true,
-                            const bool allow_exceptions = true,
+                            const bool allow_exceptions = true);
-                            const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Deserializes a given input to a JSON value using the BSON (Binary JSON) serialization format.
@@ -60,12 +58,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 `allow_exceptions` (in)
 :   whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
 
-`error_handler` (in)
-:   how to treat a string value or object key that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    BSON does not require a decoder to reject ill-formed UTF-8, so checking is opt-in: the default, `keep`, does not
-    check at all, as every binary reader did before this parameter was added; `strict` checks and throws;
-    `replace`/`ignore` sanitize the string the same way [`dump`](dump.md) would
-
 ## Return value
 
 deserialized JSON value; in case of a parse error and `allow_exceptions` set to `#!cpp false`, the return value will be
@@ -83,8 +75,6 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
   invalid string or byte array length)
 - Throws [`parse_error.114`](../../home/exceptions.md#jsonexceptionparse_error114) if an unsupported BSON record type is
   encountered
-- Throws [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) if a string value or object key is
-  not valid UTF-8 and `error_handler` is `strict`
 
 ## Complexity
 
@@ -121,7 +111,6 @@ Linear in the size of the input.
 - Added in version 3.4.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
 - Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
-- Added `error_handler` parameter in version 3.13.0.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/from_cbor.md

@@ -6,16 +6,14 @@ template<typename InputType>
 static basic_json from_cbor(InputType&& i,
                             const bool strict = true,
                             const bool allow_exceptions = true,
-                            const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error,
+                            const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error);
-                            const error_handler_t error_handler = error_handler_t::keep);
 
 // (2)
 template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_cbor(IteratorType first, SentinelType last,
                             const bool strict = true,
                             const bool allow_exceptions = true,
-                            const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error,
+                            const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error);
-                            const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Deserializes a given input to a JSON value using the CBOR (Concise Binary Object Representation) serialization format.
@@ -67,12 +65,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 :   how to treat CBOR tags (optional, `error` by default); see [`cbor_tag_handler_t`](cbor_tag_handler_t.md) for more
     information
 
-`error_handler` (in)
-:   how to treat a string value or object key that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    CBOR does not require a decoder to reject ill-formed UTF-8, so checking is opt-in: the default, `keep`, does not
-    check at all, as every binary reader did before this parameter was added; `strict` checks and throws;
-    `replace`/`ignore` sanitize the string the same way [`dump`](dump.md) would
-
 ## Return value
 
 deserialized JSON value; in case of a parse error and `allow_exceptions` set to `#!cpp false`, the return value will be
@@ -88,9 +80,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
   the end of the file was not reached when `strict` was set to true
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if unsupported features from CBOR were
   used in the given input or if the input is not valid CBOR
-- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a map key is not a string (keys of
+- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a map key is not a string (keys of other
-  other types are not supported, as JSON object keys are always strings), or if a string value or object key is not
+  types are not supported, as JSON object keys are always strings) or a string is malformed
-  valid UTF-8 and `error_handler` is `strict`
 
 ## Complexity
 
@@ -130,7 +121,6 @@ Linear in the size of the input.
 - Added `tag_handler` parameter in version 3.9.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
 - Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
-- Added `error_handler` parameter in version 3.13.0.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/from_msgpack.md

@@ -5,14 +5,12 @@
 template<typename InputType>
 static basic_json from_msgpack(InputType&& i,
                                const bool strict = true,
-                               const bool allow_exceptions = true,
+                               const bool allow_exceptions = true);
-                               const error_handler_t error_handler = error_handler_t::keep);
 // (2)
 template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_msgpack(IteratorType first, SentinelType last,
                                const bool strict = true,
-                               const bool allow_exceptions = true,
+                               const bool allow_exceptions = true);
-                               const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Deserializes a given input to a JSON value using the MessagePack serialization format.
@@ -60,12 +58,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 `allow_exceptions` (in)
 :   whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
 
-`error_handler` (in)
-:   how to treat a string value or object key that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    MessagePack's specification explicitly allows ill-formed UTF-8, so checking is opt-in: the default, `keep`, does
-    not check at all, as every binary reader did before this parameter was added; `strict` checks and throws;
-    `replace`/`ignore` sanitize the string the same way [`dump`](dump.md) would
-
 ## Return value
 
 deserialized JSON value; in case of a parse error and `allow_exceptions` set to `#!cpp false`, the return value will be
@@ -81,9 +73,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
   the end of the file was not reached when `strict` was set to true
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if unsupported features from
   MessagePack were used in the given input or if the input is not valid MessagePack
-- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a map key is not a string (keys of
+- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a map key is not a string (keys of other
-  other types are not supported, as JSON object keys are always strings), or if a string value or object key is not
+  types are not supported, as JSON object keys are always strings) or a string is malformed
-  valid UTF-8 and `error_handler` is `strict`
 
 ## Complexity
 
@@ -122,7 +113,6 @@ Linear in the size of the input.
 - Added `allow_exceptions` parameter in version 3.2.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
 - Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
-- Added `error_handler` parameter in version 3.13.0.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/from_ubjson.md

@@ -5,14 +5,12 @@
 template<typename InputType>
 static basic_json from_ubjson(InputType&& i,
                               const bool strict = true,
-                              const bool allow_exceptions = true,
+                              const bool allow_exceptions = true);
-                              const error_handler_t error_handler = error_handler_t::keep);
 // (2)
 template<typename IteratorType, typename SentinelType = IteratorType>
 static basic_json from_ubjson(IteratorType first, SentinelType last,
                               const bool strict = true,
-                              const bool allow_exceptions = true,
+                              const bool allow_exceptions = true);
-                              const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Deserializes a given input to a JSON value using the UBJSON (Universal Binary JSON) serialization format.
@@ -60,12 +58,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 `allow_exceptions` (in)
 :   whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
 
-`error_handler` (in)
-:   how to treat a string value or object key that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    UBJSON does not require a decoder to reject ill-formed UTF-8, so checking is opt-in: the default, `keep`, does not
-    check at all, as every binary reader did before this parameter was added; `strict` checks and throws;
-    `replace`/`ignore` sanitize the string the same way [`dump`](dump.md) would
-
 ## Return value
 
 deserialized JSON value; in case of a parse error and `allow_exceptions` set to `#!cpp false`, the return value will be
@@ -81,7 +73,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
   the end of the file was not reached when `strict` was set to true
 - Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs
 - Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed
-  successfully, or if a string value or object key is not valid UTF-8 and `error_handler` is `strict`
+  successfully
 - Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the size of an optimized container
   or n-dimensional array cannot be represented by `std::size_t`
 
@@ -120,7 +112,6 @@ Linear in the size of the input.
 - Added `allow_exceptions` parameter in version 3.2.0.
 - Extended container support (1) to include types with lvalue-only ADL `begin`/`end` (matching `std::begin`/`std::end` semantics) in version 3.13.0.
 - Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
-- Added `error_handler` parameter in version 3.13.0.
 
 !!! warning "Deprecation"
 

docs/mkdocs/docs/api/basic_json/to_bjdata.md

@@ -5,18 +5,15 @@
 static std::vector<std::uint8_t> to_bjdata(const basic_json& j,
                                            const bool use_size = false,
                                            const bool use_type = false,
-                                           const bjdata_version_t version = bjdata_version_t::draft2,
+                                           const bjdata_version_t version = bjdata_version_t::draft2);
-                                           const error_handler_t error_handler = error_handler_t::keep);
 
 // (2)
 static void to_bjdata(const basic_json& j, detail::output_adapter<std::uint8_t> o,
                       const bool use_size = false, const bool use_type = false,
-                      const bjdata_version_t version = bjdata_version_t::draft2,
+                      const bjdata_version_t version = bjdata_version_t::draft2);
-                      const error_handler_t error_handler = error_handler_t::keep);
 static void to_bjdata(const basic_json& j, detail::output_adapter<char> o,
                       const bool use_size = false, const bool use_type = false,
-                      const bjdata_version_t version = bjdata_version_t::draft2,
+                      const bjdata_version_t version = bjdata_version_t::draft2);
-                      const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Serializes a given JSON value `j` to a byte vector using the BJData (Binary JData) serialization format. BJData aims to
@@ -46,12 +43,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 :   which version of BJData to use (see note on "Binary values" on [BJData](../../features/binary_formats/bjdata.md));
 optional, `#!cpp bjdata_version_t::draft2` by default.
 
-`error_handler` (in)
-:   how to treat a string or object key in `j` that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    The default, `keep`, writes the ill-formed bytes to the output as is, as every version of `to_bjdata` did before
-    this parameter was added; `strict` throws; `replace`/`ignore` sanitize it the same way [`dump`](dump.md) would.
-    If [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled, the default is `strict` instead.
-
 ## Return value
 
 1. BJData serialization as byte vector
@@ -65,9 +56,6 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 
 - Throws [`other_error.502`](../../home/exceptions.md#jsonexceptionother_error502) if `use_type` is true and `use_size`
   is false.
-- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
-  not valid UTF-8 and `error_handler` is `strict` (the default only if
-  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
 
 ## Complexity
 
@@ -102,6 +90,3 @@ Linear in the size of the JSON value `j`.
 
 - Added in version 3.11.0.
 - BJData version parameter (for draft3 binary encoding) added in version 3.12.0.
-- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
-  that is not valid UTF-8 unchanged, as before; `strict` (the default if
-  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.

docs/mkdocs/docs/api/basic_json/to_bson.md

@@ -2,14 +2,11 @@
 
 ```cpp
 // (1)
-static std::vector<std::uint8_t> to_bson(const basic_json& j,
+static std::vector<std::uint8_t> to_bson(const basic_json& j);
-                                         const error_handler_t error_handler = error_handler_t::keep);
 
 // (2)
-static void to_bson(const basic_json& j, detail::output_adapter<std::uint8_t> o,
+static void to_bson(const basic_json& j, detail::output_adapter<std::uint8_t> o);
-                    const error_handler_t error_handler = error_handler_t::keep);
+static void to_bson(const basic_json& j, detail::output_adapter<char> o);
-static void to_bson(const basic_json& j, detail::output_adapter<char> o,
-                    const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 BSON (Binary JSON) is a binary format in which zero or more ordered key/value pairs are stored as a single entity (a
@@ -28,12 +25,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 `o` (in)
 :   output adapter to write serialization to
 
-`error_handler` (in)
-:   how to treat a string or object key in `j` that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    The default, `keep`, writes the ill-formed bytes to the output as is, as every version of `to_bson` did before
-    this parameter was added; `strict` throws; `replace`/`ignore` sanitize it the same way [`dump`](dump.md) would.
-    If [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled, the default is `strict` instead.
-
 ## Return value
 
 1. BSON serialization as a byte vector
@@ -55,9 +46,6 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415) if the subtype of a binary value
   exceeds 255, the maximum of the BSON binary subtype; example:
   `"subtype 70000 is too large for the BSON binary subtype (max 255)"`
-- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key is
-  not valid UTF-8 and `error_handler` is `strict` (the default only if
-  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
 
 ## Complexity
 
@@ -94,7 +82,3 @@ pass before anything is written.
 - Added in version 3.4.0.
 - Linear in the size of `j`, and no longer limited by the call stack for deeply nested values, since version 3.13.0.
 - `out_of_range.415` is now detected before anything is written, like the other exceptions above, since version 3.13.0.
-- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
-  that is not valid UTF-8 unchanged, as before; `strict` (the default if
-  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316` before anything
-  is written.

docs/mkdocs/docs/api/basic_json/to_cbor.md

@@ -2,14 +2,11 @@
 
 ```cpp
 // (1)
-static std::vector<std::uint8_t> to_cbor(const basic_json& j,
+static std::vector<std::uint8_t> to_cbor(const basic_json& j);
-                                          const error_handler_t error_handler = error_handler_t::keep);
 
 // (2)
-static void to_cbor(const basic_json& j, detail::output_adapter<std::uint8_t> o,
+static void to_cbor(const basic_json& j, detail::output_adapter<std::uint8_t> o);
-                     const error_handler_t error_handler = error_handler_t::keep);
+static void to_cbor(const basic_json& j, detail::output_adapter<char> o);
-static void to_cbor(const basic_json& j, detail::output_adapter<char> o,
-                     const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Serializes a given JSON value `j` to a byte vector using the CBOR (Concise Binary Object Representation) serialization
@@ -29,12 +26,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 `o` (in)
 :   output adapter to write serialization to
 
-`error_handler` (in)
-:   how to treat a string or object key in `j` that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    The default, `keep`, writes the ill-formed bytes to the output as is, as every version of `to_cbor` did before
-    this parameter was added; `strict` throws; `replace`/`ignore` sanitize it the same way [`dump`](dump.md) would.
-    If [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled, the default is `strict` instead.
-
 ## Return value
 
 1. CBOR serialization as a byte vector
@@ -44,12 +35,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 
 Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
 
-## Exceptions
-
-- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
-  not valid UTF-8 and `error_handler` is `strict` (the default only if
-  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
-
 ## Complexity
 
 Linear in the size of the JSON value `j`.
@@ -83,6 +68,3 @@ Linear in the size of the JSON value `j`.
 
 - Added in version 2.0.9.
 - Compact representation of floating-point numbers added in version 3.8.0.
-- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
-  that is not valid UTF-8 unchanged, as before; `strict` (the default if
-  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.

docs/mkdocs/docs/api/basic_json/to_msgpack.md

@@ -2,14 +2,11 @@
 
 ```cpp
 // (1)
-static std::vector<std::uint8_t> to_msgpack(const basic_json& j,
+static std::vector<std::uint8_t> to_msgpack(const basic_json& j);
-                                            const error_handler_t error_handler = error_handler_t::keep);
 
 // (2)
-static void to_msgpack(const basic_json& j, detail::output_adapter<std::uint8_t> o,
+static void to_msgpack(const basic_json& j, detail::output_adapter<std::uint8_t> o);
-                       const error_handler_t error_handler = error_handler_t::keep);
+static void to_msgpack(const basic_json& j, detail::output_adapter<char> o);
-static void to_msgpack(const basic_json& j, detail::output_adapter<char> o,
-                       const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Serializes a given JSON value `j` to a byte vector using the MessagePack serialization format. MessagePack is a binary
@@ -28,13 +25,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 `o` (in)
 :   output adapter to write serialization to
 
-`error_handler` (in)
-:   how to treat a string or object key in `j` that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    The default, `keep`, writes the ill-formed bytes to the output as is, as every version of `to_msgpack` did before
-    this parameter was added and as the MessagePack specification allows; `strict` throws; `replace`/`ignore` sanitize
-    it the same way [`dump`](dump.md) would. Unlike the other binary writers, the default stays `keep` even if
-    [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled.
-
 ## Return value
 
 1. MessagePack serialization as a byte vector
@@ -52,8 +42,6 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415) if the subtype of a binary value
   exceeds 255, the maximum of the MessagePack ext type; example:
   `"subtype 70000 is too large for the MessagePack ext type (max 255)"`
-- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
-  not valid UTF-8 and `error_handler` is `strict`
 
 ## Complexity
 
@@ -88,8 +76,6 @@ Linear in the size of the JSON value `j`.
 
 - Added in version 2.0.9.
 - Throws `out_of_range.412` and `out_of_range.415` since version 3.13.0.
-- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
-  that is not valid UTF-8 unchanged, as before.
 - Fixed in version 3.13.0 to serialize `number_integer_t`/`number_unsigned_t` pairs of different width correctly;
   before, integers could be serialized with the wrong value if `number_integer_t` was narrower than
   `number_unsigned_t`.

docs/mkdocs/docs/api/basic_json/to_ubjson.md

@@ -4,16 +4,13 @@
 // (1)
 static std::vector<std::uint8_t> to_ubjson(const basic_json& j,
                                            const bool use_size = false,
-                                           const bool use_type = false,
+                                           const bool use_type = false);
-                                           const error_handler_t error_handler = error_handler_t::keep);
 
 // (2)
 static void to_ubjson(const basic_json& j, detail::output_adapter<std::uint8_t> o,
-                      const bool use_size = false, const bool use_type = false,
+                      const bool use_size = false, const bool use_type = false);
-                      const error_handler_t error_handler = error_handler_t::keep);
 static void to_ubjson(const basic_json& j, detail::output_adapter<char> o,
-                      const bool use_size = false, const bool use_type = false,
+                      const bool use_size = false, const bool use_type = false);
-                      const error_handler_t error_handler = error_handler_t::keep);
 ```
 
 Serializes a given JSON value `j` to a byte vector using the UBJSON (Universal Binary JSON) serialization format. UBJSON
@@ -39,12 +36,6 @@ The exact mapping and its limitations are described on a [dedicated page](../../
 :   whether to add type annotations to container types (must be combined with `#!cpp use_size = true`); optional,
     `#!cpp false` by default.
 
-`error_handler` (in)
-:   how to treat a string or object key in `j` that is not valid UTF-8; see [`error_handler_t`](error_handler_t.md).
-    The default, `keep`, writes the ill-formed bytes to the output as is, as every version of `to_ubjson` did before
-    this parameter was added; `strict` throws; `replace`/`ignore` sanitize it the same way [`dump`](dump.md) would.
-    If [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled, the default is `strict` instead.
-
 ## Return value
 
 1. UBJSON serialization as a byte vector
@@ -58,9 +49,6 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 
 - Throws [`other_error.502`](../../home/exceptions.md#jsonexceptionother_error502) if `use_type` is true and `use_size`
   is false.
-- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
-  not valid UTF-8 and `error_handler` is `strict` (the default only if
-  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
 
 ## Complexity
 
@@ -94,6 +82,3 @@ Linear in the size of the JSON value `j`.
 ## Version history
 
 - Added in version 3.1.0.
-- Added `error_handler` parameter in version 3.13.0. Its default, `keep`, writes the bytes of a string or object key
-  that is not valid UTF-8 unchanged, as before; `strict` (the default if
-  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.

docs/mkdocs/docs/api/macros/index.md

@@ -18,8 +18,6 @@ header. See also the [macro overview page](../../features/macros.md).
 
 - [**JSON_PRECISE_STREAM_POSITION**](json_precise_stream_position.md) - opt in to leaving an input stream positioned
   right after a parsed number
-- [**JSON_STRICT_BINARY_UTF8**](json_strict_binary_utf8.md) - opt in to checking strings for valid UTF-8 in the CBOR,
-  UBJSON, BJData, and BSON writers
 - [**JSON_STRICT_NUL_HANDLING**](json_strict_nul_handling.md) - opt in to rejecting a NUL byte in the input instead of
   treating it as end of input
 

docs/mkdocs/docs/api/macros/json_strict_binary_utf8.md

@@ -1,101 +0,0 @@
-# JSON_STRICT_BINARY_UTF8
-
-```cpp
-#define JSON_STRICT_BINARY_UTF8 /* value */
-```
-
-When defined to `1`, the `error_handler` parameter of the binary writers [`to_cbor`](../basic_json/to_cbor.md),
-[`to_ubjson`](../basic_json/to_ubjson.md), [`to_bjdata`](../basic_json/to_bjdata.md), and
-[`to_bson`](../basic_json/to_bson.md) defaults to [`error_handler_t::strict`](../basic_json/error_handler_t.md) instead
-of `error_handler_t::keep`. These writers then check every string value and object key for valid UTF-8 and throw
-[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) for ill-formed UTF-8, like
-[`dump`](../basic_json/dump.md) does. Without it, they write the bytes unchanged. An `error_handler` passed explicitly
-always takes precedence.
-
-The macro does not affect:
-
-- [`to_msgpack`](../basic_json/to_msgpack.md): the MessagePack specification allows a `str` value to contain bytes that
-  are not valid UTF-8, so its `error_handler` always defaults to `keep`.
-- [`to_bon8`](../basic_json/to_bon8.md): BON8 always checks, because the UTF-8 lead bytes mark where a string ends.
-- The binary readers ([`from_cbor`](../basic_json/from_cbor.md), [`from_msgpack`](../basic_json/from_msgpack.md),
-  [`from_ubjson`](../basic_json/from_ubjson.md), [`from_bjdata`](../basic_json/from_bjdata.md),
-  [`from_bson`](../basic_json/from_bson.md)): none of these formats requires a decoder to reject ill-formed UTF-8, so
-  they always return the bytes unchanged.
-
-## Default definition
-
-The default value is `0` (disabled, the behavior of version 3.12.0 and earlier is preserved).
-
-```cpp
-#define JSON_STRICT_BINARY_UTF8 0
-```
-
-## Notes
-
-!!! note "Background"
-
-    CBOR, UBJSON, BJData, and BSON all require strings to be UTF-8. Up to version 3.12.0, the writers did not check
-    this, so they could produce output that other decoders reject. Checking by default would break code that stores
-    other encodings (for instance ISO 8859-1) in a string and only ever writes it to a binary format. You can pass
-    `error_handler_t::strict` to each call, or use this macro to check by default ahead of version 4.0.0, where
-    `strict` is planned to become the default (see
-    [#5529](https://github.com/nlohmann/json/issues/5529) and [#5651](https://github.com/nlohmann/json/issues/5651)).
-
-!!! warning "Opt-in only"
-
-    This macro must be defined **before** including `<nlohmann/json.hpp>`. Defining it after the include has no
-    effect.
-
-!!! note "ABI compatibility"
-
-    The value of this macro is encoded in the [namespace](../../features/namespace.md) (tag `_sbu8`), resulting in
-    distinct symbol names. Translation units compiled with and without it can therefore be linked into the same program
-    without One Definition Rule (ODR) violations, but they cannot exchange instances of library types.
-
-## Examples
-
-??? example "Default behavior (macro not defined)"
-
-    Without the macro, the bytes are written unchanged:
-
-    ```cpp
-    #include <nlohmann/json.hpp>
-
-    using json = nlohmann::json;
-
-    int main()
-    {
-        auto v = json::to_cbor(json("\xFF"));
-        // v is {0x61, 0xFF}
-    }
-    ```
-
-??? example "Opt-in check (macro defined to 1)"
-
-    With the macro, ill-formed UTF-8 is rejected:
-
-    ```cpp
-    #define JSON_STRICT_BINARY_UTF8 1
-    #include <nlohmann/json.hpp>
-
-    using json = nlohmann::json;
-
-    int main()
-    {
-        auto v = json::to_cbor(json("\xFF"));
-        // throws type_error.316: invalid UTF-8 byte at index 0: 0xFF
-    }
-    ```
-
-## See also
-
-- [**to_cbor**](../basic_json/to_cbor.md) - create a CBOR serialization of a JSON value
-- [**to_ubjson**](../basic_json/to_ubjson.md) - create a UBJSON serialization of a JSON value
-- [**to_bjdata**](../basic_json/to_bjdata.md) - create a BJData serialization of a JSON value
-- [**to_bson**](../basic_json/to_bson.md) - create a BSON serialization of a JSON value
-- [**error_handler_t**](../basic_json/error_handler_t.md) - how [`dump`](../basic_json/dump.md) treats ill-formed UTF-8
-
-## Version history
-
-- Added in version 3.13.0.
-- Planned to become the default (with the macro removed) in version 4.0.0.

docs/mkdocs/docs/examples/error_handler_t.cpp

@@ -20,6 +20,5 @@ int main()
               << j_invalid.dump(-1, ' ', false, json::error_handler_t::replace)
               << "\nstring with ignored invalid characters: "
               << j_invalid.dump(-1, ' ', false, json::error_handler_t::ignore)
-              << "\nstring with the invalid byte kept as is (" << j_invalid.dump(-1, ' ', false, json::error_handler_t::keep).size()
+              << '\n';
-              << " bytes, not valid UTF-8 itself)\n";
 }

docs/mkdocs/docs/examples/error_handler_t.output

@@ -1,4 +1,3 @@
 [json.exception.type_error.316] invalid UTF-8 byte at index 2: 0xA9
 string with replaced invalid characters: "ä�ü"
 string with ignored invalid characters: "äü"
-string with the invalid byte kept as is (7 bytes, not valid UTF-8 itself)

docs/mkdocs/docs/features/binary_formats/bjdata.md

@@ -63,15 +63,6 @@ The library uses the following mapping from JSON values types to BJData types ac
 
       - strings with more than 18446744073709551615 bytes, i.e., 2<sup>64</sup>-1 bytes (theoretical)
 
-!!! warning "UTF-8 validation of string values and object keys"
-
-    BJData strings must use UTF-8 encoding. By default (the [`error_handler`](../../api/basic_json/to_bjdata.md)
-    parameter left at `keep`), `to_bjdata()` writes the bytes of string values and object keys unchanged, even if they
-    are not valid UTF-8. With `error_handler_t::strict`, it throws
-    [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) for ill-formed UTF-8 instead;
-    `replace`/`ignore` sanitize the string. [`JSON_STRICT_BINARY_UTF8`](../../api/macros/json_strict_binary_utf8.md)
-    makes `strict` the default.
-
 !!! info "Unused BJData markers"
 
     The following markers are not used in the conversion:
@@ -217,19 +208,6 @@ The library maps BJData types to JSON value types as follows:
 
     The mapping is **complete** in the sense that any BJData value can be converted to a JSON value.
 
-!!! warning "Ill-formed UTF-8 in string values and object keys"
-
-    BJData strings must use UTF-8 encoding, but checking it on read is opt-in: with the
-    [`error_handler`](../../api/basic_json/from_bjdata.md) parameter left at `keep` (the default), `from_bjdata()`
-    accepts a string value or object key whose bytes are not valid UTF-8 and hands them back unchanged. Passing
-    `error_handler_t::strict` makes `from_bjdata()` check and throw
-    [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) for ill-formed UTF-8, and
-    `replace`/`ignore` sanitize the string instead of keeping it. However,
-    [`dump()`](../../api/basic_json/dump.md) still requires valid UTF-8 and throws
-    [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) for a value read with the default
-    `keep` handler, unless an error handler is passed that replaces or ignores the ill-formed bytes. `to_bjdata()`'s
-    own `error_handler` parameter defaults to `keep` (see above), so such a value is written back unchanged.
-
 !!! info "Round trips"
 
     A value returned by [`from_bjdata`](../../api/basic_json/from_bjdata.md) can be serialized with

docs/mkdocs/docs/features/binary_formats/bson.md

@@ -109,21 +109,14 @@ The library maps BSON record types to JSON value types as follows:
     If BSON input must be validated for strict specification compliance, validate it separately before passing it to
     `from_bson()`.
 
-!!! warning "Ill-formed UTF-8 in string values"
+!!! warning "UTF-8 validation of string values"
 
-    The BSON specification requires `string` values (type `0x02`) to be valid UTF-8, but this is not required of a
+    The BSON specification requires `string` values (type `0x02`) to be valid UTF-8. This library validates the
-    decoder, so checking is opt-in: with the [`error_handler`](../../api/basic_json/from_bson.md) parameter left at
+    bytes of every such string at decode time and rejects ill-formed UTF-8 with a
-    `keep` (the default), `from_bson()` accepts a `string` value whose bytes are not valid UTF-8 and hands them back
+    [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) exception (or, with `allow_exceptions`
-    unchanged. Passing `error_handler_t::strict` makes `from_bson()` check and throw
+    set to `false`, a discarded value), rather than only failing later when the resulting value is dumped. Element
-    [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) for ill-formed UTF-8, and
+    (key) names and `binary` values (type `0x05`) are unaffected and are never validated, since they are read
-    `replace`/`ignore` sanitize the string instead of keeping it. However, [`dump()`](../../api/basic_json/dump.md)
+    byte-by-byte as a C string, or are not required to hold text, respectively.
-    still requires valid UTF-8 and throws [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) for a
-    value read with the default `keep` handler, unless an error handler is passed that replaces or ignores the
-    ill-formed bytes. `to_bson()`'s own `error_handler` parameter defaults to `keep`, so such a string value or element
-    (key) name is written unchanged; with `strict` (the default if
-    [`JSON_STRICT_BINARY_UTF8`](../../api/macros/json_strict_binary_utf8.md) is enabled), it throws the same exception
-    instead. Element (key) names are never validated on read, since they are read byte-by-byte as a C string. `binary`
-    values (type `0x05`) are unaffected, since they are not required to hold text.
 
 ??? example
 

docs/mkdocs/docs/features/binary_formats/cbor.md

@@ -189,21 +189,15 @@ The library maps CBOR types to JSON value types as follows:
     ([RFC 8392](https://www.rfc-editor.org/rfc/rfc8392.html)), cannot be read with this library and need a
     general-purpose CBOR library instead.
 
-!!! warning "Ill-formed UTF-8 in text strings"
+!!! warning "UTF-8 validation of text strings"
 
-    [RFC 8949, Section 3.1](https://www.rfc-editor.org/rfc/rfc8949.html#section-3.1) requires CBOR text strings (major
+    [RFC 8949, Section 3.1](https://www.rfc-editor.org/rfc/rfc8949.html#section-3.1) requires CBOR text strings
-    type 3) to be valid UTF-8, but leaves it up to the decoder whether to enforce this, so checking is opt-in: with the
+    (major type 3) to be valid UTF-8. This library validates the bytes of every text string (object keys included) at
-    [`error_handler`](../../api/basic_json/from_cbor.md) parameter left at `keep` (the default), `from_cbor()` accepts a
+    decode time and rejects ill-formed UTF-8 with a
-    text string (object keys included) whose bytes are not valid UTF-8 and hands them back unchanged. Passing
+    [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) exception (or, with
-    `error_handler_t::strict` makes `from_cbor()` check and throw
+    `allow_exceptions` set to `false`, a discarded value), rather than only failing later when the resulting value is
-    [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) for ill-formed UTF-8, and
+    dumped. Byte strings (major type 2) are unaffected and are never validated, since they are not required to hold
-    `replace`/`ignore` sanitize the string instead of keeping it. However, [`dump()`](../../api/basic_json/dump.md)
+    text.
-    still requires valid UTF-8 and throws [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) for a
-    value read with the default `keep` handler, unless an error handler is passed that replaces or ignores the
-    ill-formed bytes. `to_cbor()`'s own [`error_handler`](../../api/basic_json/to_cbor.md) parameter defaults to `keep`,
-    so such a value is written back unchanged; with `strict` (the default if
-    [`JSON_STRICT_BINARY_UTF8`](../../api/macros/json_strict_binary_utf8.md) is enabled), it throws the same exception
-    instead. Byte strings (major type 2) are unaffected, since they are not required to hold text.
 
 !!! warning "Tagged items"
 

docs/mkdocs/docs/features/binary_formats/messagepack.md

@@ -153,23 +153,14 @@ The library maps MessagePack types to JSON value types as follows:
     This applies to the [SAX interface](../parsing/sax_interface.md) as well, as the key is read before it is passed
     on. Such input needs a general-purpose MessagePack library instead.
 
-!!! warning "Ill-formed UTF-8 in string values"
+!!! warning "UTF-8 validation of string values"
 
-    The MessagePack specification explicitly allows a `str` value (`fixstr`, `str 8`, `str 16`, `str 32`) to contain
+    The MessagePack specification requires `str` values (`fixstr`, `str 8`, `str 16`, `str 32`) to be valid UTF-8.
-    a byte sequence that is not valid UTF-8, and expects a deserializer to hand the original bytes back unchanged.
+    This library validates the bytes of every such string (object keys included) at decode time and rejects
-    This library follows that by default: with its
+    ill-formed UTF-8 with a [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) exception (or,
-    [`error_handler`](../../api/basic_json/from_msgpack.md) parameter left at `keep` (the default),
+    with `allow_exceptions` set to `false`, a discarded value), rather than only failing later when the resulting
-    `from_msgpack()` reads `str` bytes (object keys included) as-is, without validating them, so such a value
+    value is dumped. `bin`/`ext`/`fixext` values are unaffected and are never validated, since they are not required
-    round-trips through `from_msgpack(to_msgpack(j))` byte for byte. Passing `error_handler_t::strict` makes
+    to hold text.
-    `from_msgpack()` check anyway and throw
-    [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) for ill-formed UTF-8, and
-    `replace`/`ignore` sanitize the string instead of keeping it. `to_msgpack()` also writes `str` bytes as-is by
-    default, since the specification permits it; its [`error_handler`](../../api/basic_json/to_msgpack.md) parameter
-    can be set to `strict` to throw [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) instead, or
-    to `replace`/`ignore` to sanitize the string, for instance for a decoder that rejects ill-formed UTF-8. However,
-    [`dump()`](../../api/basic_json/dump.md) still requires valid UTF-8 and throws
-    [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) for a value read this way with the
-    default `keep` handler, unless an error handler is passed that replaces or ignores the ill-formed bytes.
 
 ??? example
 

docs/mkdocs/docs/features/binary_formats/ubjson.md

@@ -47,15 +47,6 @@ The library uses the following mapping from JSON values types to UBJSON types ac
 
       - strings with more than 9223372036854775807 bytes (theoretical)
 
-!!! warning "UTF-8 validation of string values and object keys"
-
-    UBJSON's required string encoding is UTF-8. By default (the [`error_handler`](../../api/basic_json/to_ubjson.md)
-    parameter left at `keep`), `to_ubjson()` writes the bytes of string values and object keys unchanged, even if they
-    are not valid UTF-8. With `error_handler_t::strict`, it throws
-    [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) for ill-formed UTF-8 instead;
-    `replace`/`ignore` sanitize the string. [`JSON_STRICT_BINARY_UTF8`](../../api/macros/json_strict_binary_utf8.md)
-    makes `strict` the default.
-
 !!! info "Unused UBJSON markers"
 
     The following markers are not used in the conversion:
@@ -129,19 +120,6 @@ The library maps UBJSON types to JSON value types as follows:
 
     The mapping is **complete** in the sense that any UBJSON value can be converted to a JSON value.
 
-!!! warning "Ill-formed UTF-8 in string values and object keys"
-
-    UBJSON's required string encoding is UTF-8, but checking it on read is opt-in: with the
-    [`error_handler`](../../api/basic_json/from_ubjson.md) parameter left at `keep` (the default), `from_ubjson()`
-    accepts a string value or object key whose bytes are not valid UTF-8 and hands them back unchanged. Passing
-    `error_handler_t::strict` makes `from_ubjson()` check and throw
-    [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) for ill-formed UTF-8, and
-    `replace`/`ignore` sanitize the string instead of keeping it. However,
-    [`dump()`](../../api/basic_json/dump.md) still requires valid UTF-8 and throws
-    [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) for a value read with the default
-    `keep` handler, unless an error handler is passed that replaces or ignores the ill-formed bytes. `to_ubjson()`'s
-    own `error_handler` parameter defaults to `keep` (see above), so such a value is written back unchanged.
-
 ??? example
 
     ```cpp

docs/mkdocs/docs/features/macros.md

@@ -138,20 +138,6 @@ using the library with compilers that do not fully support C++11 and may only wo
 
 See [full documentation of `JSON_SKIP_UNSUPPORTED_COMPILER_CHECK`](../api/macros/json_skip_unsupported_compiler_check.md).
 
-## `JSON_STRICT_BINARY_UTF8`
-
-When defined to `1`, [`to_cbor`](../api/basic_json/to_cbor.md), [`to_ubjson`](../api/basic_json/to_ubjson.md),
-[`to_bjdata`](../api/basic_json/to_bjdata.md), and [`to_bson`](../api/basic_json/to_bson.md) throw
-[`type_error.316`](../home/exceptions.md#jsonexceptiontype_error316) for a string value or object key that is not
-valid UTF-8. The default value is `0`, which writes the bytes unchanged as before version 3.13.0; this is planned to
-become the default in version 4.0.0.
-
-The check can also be enabled with the CMake option
-[`JSON_StrictBinaryUTF8`](../integration/cmake.md#json_strictbinaryutf8) (`OFF` by default) which sets
-`JSON_STRICT_BINARY_UTF8` accordingly.
-
-See [full documentation of `JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md).
-
 ## `JSON_STRICT_NUL_HANDLING`
 
 When defined to `1`, a `'\0'` (NUL) byte anywhere in the input is rejected with `parse_error.101`, like any other

docs/mkdocs/docs/features/namespace.md

@@ -20,7 +20,6 @@ The complete default namespace name is derived as follows:
       `_bics`.
     - [`JSON_PRECISE_STREAM_POSITION`](../api/macros/json_precise_stream_position.md) defined non-zero appends `_psp`.
     - [`JSON_STRICT_NUL_HANDLING`](../api/macros/json_strict_nul_handling.md) defined non-zero appends `_snul`.
-    - [`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md) defined non-zero appends `_sbu8`.
 - The inline namespace ends with the suffix `_v` followed by the 3 components of the version number separated by
   underscores. To omit the version component, see [Disabling the version component](#disabling-the-version-component)
   below.

docs/mkdocs/docs/home/exceptions.md

@@ -341,10 +341,7 @@ An unexpected byte was read in a [binary format](../features/binary_formats/inde
 
 A string could not be read from a [binary format](../features/binary_formats/index.md): either a value that is not a
 string was read where one was required (for instance as a map key), the string's length specification is invalid, or
-the string's bytes are not valid UTF-8 and the `error_handler` parameter of the corresponding `from_*` function is
+the string's bytes are not valid UTF-8.
-set to `strict`. By default (`error_handler_t::keep`), the bytes of a string are not checked for valid UTF-8 on read;
-see the ill-formed UTF-8 notes on the individual [binary format](../features/binary_formats/index.md) pages for how
-such a string is handled depending on `error_handler`.
 
 CBOR and MessagePack allow map keys of any type, but JSON object keys are always strings. Maps with keys of any other
 type (for instance integers or `null`) are therefore not supported; see the notes on
@@ -752,12 +749,6 @@ The `unflatten()` function only works for an object whose keys are JSON Pointers
 
 The `dump()` function only works with UTF-8 encoded strings; that is, if you assign a `std::string` to a JSON value, make sure it is UTF-8 encoded.
 
-The binary writers [`to_cbor()`](../api/basic_json/to_cbor.md), [`to_ubjson()`](../api/basic_json/to_ubjson.md),
-[`to_bjdata()`](../api/basic_json/to_bjdata.md), and [`to_bson()`](../api/basic_json/to_bson.md) throw this exception
-as well for a string value or object key that is not valid UTF-8 if their `error_handler` is `strict` (the default if
-[`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md) is enabled). So does
-[`to_msgpack()`](../api/basic_json/to_msgpack.md) if `error_handler_t::strict` is passed.
-
 !!! failure "Example message"
 
     Calling `dump()` on a JSON value containing an ISO 8859-1 encoded string:

docs/mkdocs/docs/integration/cmake.md

@@ -204,11 +204,6 @@ Use the non-amalgamated version of the library. This option is `ON` by default.
 
 Treat the library headers like system headers (i.e., adding `SYSTEM` to the [`target_include_directories`](https://cmake.org/cmake/help/latest/command/target_include_directories.html) call) to check for this library by tools like Clang-Tidy. This option is `OFF` by default.
 
-### `JSON_StrictBinaryUTF8`
-
-Check string values and object keys for valid UTF-8 in the CBOR, UBJSON, BJData, and BSON writers, by defining the
-macro [`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md). This option is `OFF` by default.
-
 ### `JSON_StrictNulHandling`
 
 Reject a `'\0'` (NUL) byte in the input instead of treating it as end of input, by defining the macro

docs/mkdocs/mkdocs.yml

@@ -301,7 +301,6 @@ nav:
           - 'JSON_PRECISE_STREAM_POSITION': api/macros/json_precise_stream_position.md
           - 'JSON_SKIP_LIBRARY_VERSION_CHECK': api/macros/json_skip_library_version_check.md
           - 'JSON_SKIP_UNSUPPORTED_COMPILER_CHECK': api/macros/json_skip_unsupported_compiler_check.md
-          - 'JSON_STRICT_BINARY_UTF8': api/macros/json_strict_binary_utf8.md
           - 'JSON_STRICT_NUL_HANDLING': api/macros/json_strict_nul_handling.md
           - 'JSON_USE_GLOBAL_UDLS': api/macros/json_use_global_udls.md
           - 'JSON_USE_IMPLICIT_CONVERSIONS': api/macros/json_use_implicit_conversions.md

include/nlohmann/detail/abi_macros.hpp

@@ -46,10 +46,6 @@
     #define JSON_STRICT_NUL_HANDLING 0
 #endif
 
-#ifndef JSON_STRICT_BINARY_UTF8
-    #define JSON_STRICT_BINARY_UTF8 0
-#endif
-
 #if JSON_DIAGNOSTICS
     #define NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS _diag
 #else
@@ -86,20 +82,14 @@
     #define NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING
 #endif
 
-#if JSON_STRICT_BINARY_UTF8
-    #define NLOHMANN_JSON_ABI_TAG_STRICT_BINARY_UTF8 _sbu8
-#else
-    #define NLOHMANN_JSON_ABI_TAG_STRICT_BINARY_UTF8
-#endif
-
 #ifndef NLOHMANN_JSON_NAMESPACE_NO_VERSION
     #define NLOHMANN_JSON_NAMESPACE_NO_VERSION 0
 #endif
 
 // Construct the namespace ABI tags component
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g) json_abi ## a ## b ## c ## d ## e ## f ## g
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f) json_abi ## a ## b ## c ## d ## e ## f
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f, g) \
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f) \
-    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g)
+    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f)
 
 #define NLOHMANN_JSON_ABI_TAGS                                       \
     NLOHMANN_JSON_ABI_TAGS_CONCAT(                                   \
@@ -108,8 +98,7 @@
             NLOHMANN_JSON_ABI_TAG_DIAGNOSTIC_POSITIONS,              \
             NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS,         \
             NLOHMANN_JSON_ABI_TAG_PRECISE_STREAM_POSITION,           \
-            NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING,               \
+            NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING)
-            NLOHMANN_JSON_ABI_TAG_STRICT_BINARY_UTF8)
 
 // Construct the namespace version component
 #define NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT_EX(major, minor, patch) \

include/nlohmann/detail/conversions/from_json.hpp

@@ -27,7 +27,6 @@
 #include <nlohmann/detail/meta/identity_tag.hpp>
 #include <nlohmann/detail/meta/std_fs.hpp>
 #include <nlohmann/detail/meta/type_traits.hpp>
-#include <nlohmann/detail/meta/logic.hpp>
 #include <nlohmann/detail/string_concat.hpp>
 #include <nlohmann/detail/value_t.hpp>
 
@@ -211,62 +210,29 @@ inline void from_json(const BasicJsonType& j, std::valarray<T>& l)
     });
 }
 
+// element is not itself a C array: read it directly
+template<typename BasicJsonType, typename T>
+auto from_json_c_array_element(const BasicJsonType& j, T& e)
+-> decltype(e = j.template get<T>(), void())
+{
+    e = j.template get<T>();
+}
+
+// element is itself a C array: recurse one dimension at a time, so any rank is supported
 template<typename BasicJsonType, typename T, std::size_t N>
-auto from_json(const BasicJsonType& j, T (&arr)[N])  // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+void from_json_c_array_element(const BasicJsonType& j, T (&arr)[N])  // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
--> decltype(j.template get<T>(), void())
 {
     for (std::size_t i = 0; i < N; ++i)
     {
-        arr[i] = j.at(i).template get<T>();
+        from_json_c_array_element(j.at(i), arr[i]);
     }
 }
 
-template<typename BasicJsonType, typename T, std::size_t N1, std::size_t N2>
+template<typename BasicJsonType, typename T, std::size_t N>
-auto from_json(const BasicJsonType& j, T (&arr)[N1][N2])  // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+auto from_json(const BasicJsonType& j, T (&arr)[N])  // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
--> decltype(j.template get<T>(), void())
+-> decltype(j.template get<typename std::remove_all_extents<T>::type>(), void())
 {
-    for (std::size_t i1 = 0; i1 < N1; ++i1)
+    from_json_c_array_element(j, arr);
-    {
-        for (std::size_t i2 = 0; i2 < N2; ++i2)
-        {
-            arr[i1][i2] = j.at(i1).at(i2).template get<T>();
-        }
-    }
-}
-
-template<typename BasicJsonType, typename T, std::size_t N1, std::size_t N2, std::size_t N3>
-auto from_json(const BasicJsonType& j, T (&arr)[N1][N2][N3])  // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
--> decltype(j.template get<T>(), void())
-{
-    for (std::size_t i1 = 0; i1 < N1; ++i1)
-    {
-        for (std::size_t i2 = 0; i2 < N2; ++i2)
-        {
-            for (std::size_t i3 = 0; i3 < N3; ++i3)
-            {
-                arr[i1][i2][i3] = j.at(i1).at(i2).at(i3).template get<T>();
-            }
-        }
-    }
-}
-
-template<typename BasicJsonType, typename T, std::size_t N1, std::size_t N2, std::size_t N3, std::size_t N4>
-auto from_json(const BasicJsonType& j, T (&arr)[N1][N2][N3][N4])  // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
--> decltype(j.template get<T>(), void())
-{
-    for (std::size_t i1 = 0; i1 < N1; ++i1)
-    {
-        for (std::size_t i2 = 0; i2 < N2; ++i2)
-        {
-            for (std::size_t i3 = 0; i3 < N3; ++i3)
-            {
-                for (std::size_t i4 = 0; i4 < N4; ++i4)
-                {
-                    arr[i1][i2][i3][i4] = j.at(i1).at(i2).at(i3).at(i4).template get<T>();
-                }
-            }
-        }
-    }
 }
 
 template<typename BasicJsonType>
@@ -286,20 +252,33 @@ auto from_json_array_impl(const BasicJsonType& j, std::array<T, N>& arr,
     }
 }
 
+// reserve() is called through this pair (modeled on from_json_object_reserve)
+// so from_json_array_impl below has a single body for both ConstructibleArrayType
+// that support reserve() and those that don't.
+template<typename ConstructibleArrayType>
+auto from_json_array_reserve(ConstructibleArrayType& arr, typename ConstructibleArrayType::size_type size, priority_tag<1> /*unused*/)
+-> decltype(arr.reserve(size), void())
+{
+    arr.reserve(size);
+}
+
+template<typename ConstructibleArrayType>
+void from_json_array_reserve(ConstructibleArrayType& /*arr*/, std::size_t /*size*/, priority_tag<0> /*unused*/)
+{}
+
 template<typename BasicJsonType, typename ConstructibleArrayType,
          enable_if_t<
              std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
              int> = 0>
 auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, priority_tag<1> /*unused*/)
 -> decltype(
-    arr.reserve(std::declval<typename ConstructibleArrayType::size_type>()),
     j.template get<typename ConstructibleArrayType::value_type>(),
     void())
 {
     using std::end;
 
     ConstructibleArrayType ret;
-    ret.reserve(j.size());
+    from_json_array_reserve(ret, j.size(), priority_tag<1> {});
     std::transform(j.begin(), j.end(),
                    std::inserter(ret, end(ret)), [](const BasicJsonType & i)
     {
@@ -310,27 +289,6 @@ auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, p
     arr = std::move(ret);
 }
 
-template<typename BasicJsonType, typename ConstructibleArrayType,
-         enable_if_t<
-             std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
-             int> = 0>
-inline void from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr,
-                                 priority_tag<0> /*unused*/)
-{
-    using std::end;
-
-    ConstructibleArrayType ret;
-    std::transform(
-        j.begin(), j.end(), std::inserter(ret, end(ret)),
-        [](const BasicJsonType & i)
-    {
-        // get<BasicJsonType>() returns *this, this won't call a from_json
-        // method when value_type is BasicJsonType
-        return i.template get<typename ConstructibleArrayType::value_type>();
-    });
-    arr = std::move(ret);
-}
-
 template < typename BasicJsonType, typename ConstructibleArrayType,
            enable_if_t <
                is_constructible_array_type<BasicJsonType, ConstructibleArrayType>::value&&
@@ -433,9 +391,7 @@ inline void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
 }
 
 // overload for arithmetic types, not chosen for basic_json template arguments
-// (BooleanType, etc.); note: Is it really necessary to provide explicit
+// (BooleanType, etc.)
-// overloads for boolean_t etc. in case of a custom BooleanType which is not
-// an arithmetic type?
 template < typename BasicJsonType, typename ArithmeticType,
            enable_if_t <
                std::is_arithmetic<ArithmeticType>::value&&
@@ -531,7 +487,7 @@ inline void from_json_tuple_impl(const BasicJsonType& j, std::pair<A1, A2>& p, p
 template<typename BasicJsonType, typename... Args>
 std::tuple<Args...> from_json_tuple_impl(const BasicJsonType& j, identity_tag<std::tuple<Args...>> /*unused*/, priority_tag<2> /*unused*/)
 {
-    static_assert(cxpr_and<cxpr_or<cxpr_not<std::is_reference<Args>>, is_compatible_reference_type<const BasicJsonType&, Args>>...>::value,
+    static_assert(conjunction<disjunction<negation<std::is_reference<Args>>, is_compatible_reference_type<const BasicJsonType&, Args>>...>::value,
                   "Can not return a tuple containing references to types not contained in a Json, try Json::get_to()");
     return from_json_tuple_impl_base<1, Args...>(j, index_sequence_for<Args...> {});
 }
@@ -554,10 +510,10 @@ auto from_json(const BasicJsonType& j, TupleRelated&& t)
     return from_json_tuple_impl(j, std::forward<TupleRelated>(t), priority_tag<3> {});
 }
 
-template < typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
+// shared body for std::map/std::unordered_map with a non-string Key: both
-           typename = enable_if_t < !std::is_constructible <
+// containers are read from an array of [key, value] pairs the same way
-                                        typename BasicJsonType::string_t, Key >::value >>
+template<typename BasicJsonType, typename MapType>
-inline void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>& m)
+void from_json_pair_array_to_map(const BasicJsonType& j, MapType& m)
 {
     if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
     {
@@ -570,33 +526,29 @@ inline void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allo
         {
             JSON_THROW(type_error::create(302, concat("type must be array, but is ", p.type_name()), &p));
         }
-        m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
+        m.emplace(p.at(0).template get<typename MapType::key_type>(), p.at(1).template get<typename MapType::mapped_type>());
     }
 }
 
+template < typename BasicJsonType, typename Key, typename Value, typename Compare, typename Allocator,
+           typename = enable_if_t < !std::is_constructible <
+                                        typename BasicJsonType::string_t, Key >::value >>
+void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>& m)
+{
+    from_json_pair_array_to_map(j, m);
+}
+
 template < typename BasicJsonType, typename Key, typename Value, typename Hash, typename KeyEqual, typename Allocator,
            typename = enable_if_t < !std::is_constructible <
                                         typename BasicJsonType::string_t, Key >::value >>
-inline void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyEqual, Allocator>& m)
+void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyEqual, Allocator>& m)
 {
-    if (JSON_HEDLEY_UNLIKELY(!j.is_array()))
+    from_json_pair_array_to_map(j, m);
-    {
-        JSON_THROW(type_error::create(302, concat("type must be array, but is ", j.type_name()), &j));
-    }
-    m.clear();
-    for (const auto& p : j)
-    {
-        if (JSON_HEDLEY_UNLIKELY(!p.is_array()))
-        {
-            JSON_THROW(type_error::create(302, concat("type must be array, but is ", p.type_name()), &p));
-        }
-        m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
-    }
 }
 
 #if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
 
-// Workaround for MSVC 19.51 (and possibly later): in large in large cpp files, the compiler may fail to resolve with generic has_from_json (issue #4996)
+// Workaround for MSVC 19.51 (and possibly later): in large cpp files, the compiler may fail to resolve with generic has_from_json (issue #4996)
 template<typename BasicJsonType>
 struct has_from_json<BasicJsonType, std_fs::path, void> : std::true_type {};
 

include/nlohmann/detail/conversions/to_json.hpp

@@ -178,7 +178,7 @@ struct external_constructor<value_t::array>
 
     template < typename BasicJsonType, typename CompatibleArrayType,
                enable_if_t < !std::is_same<CompatibleArrayType, typename BasicJsonType::array_t>::value
-#if JSON_HAS_RANGES && !defined(__MINGW32__)
+#if JSON_HAS_RANGE_VIEW_CONVERSION
                              && !is_compatible_range_view<CompatibleArrayType>::value
 #endif
                              , int > = 0 >
@@ -222,9 +222,7 @@ struct external_constructor<value_t::array>
         j.assert_invariant();
     }
 
-    // std::ranges does not work properly on MinGW due to incomplete C++20 support
+#if JSON_HAS_RANGE_VIEW_CONVERSION
-    // see https://github.com/nlohmann/json/issues/4916
-#if JSON_HAS_RANGES && !defined(__MINGW32__)
     template<typename BasicJsonType, typename CompatibleArrayType,
              enable_if_t<is_compatible_range_view<std::remove_cvref_t<CompatibleArrayType>>::value, int> = 0>
     static void construct(BasicJsonType& j, CompatibleArrayType && arr)
@@ -379,7 +377,7 @@ template < typename BasicJsonType, typename CompatibleArrayType,
                          !std::is_same<typename BasicJsonType::binary_t, CompatibleArrayType>::value&&
                          !is_compatible_binary_type<BasicJsonType, CompatibleArrayType>::value&&
                          !is_basic_json<CompatibleArrayType>::value
-#if JSON_HAS_RANGES && !defined(__MINGW32__)
+#if JSON_HAS_RANGE_VIEW_CONVERSION
     && !is_compatible_range_view<CompatibleArrayType>::value
 #endif
                          ,
@@ -389,7 +387,7 @@ inline void to_json(BasicJsonType& j, const CompatibleArrayType& arr)
     external_constructor<value_t::array>::construct(j, arr);
 }
 
-#if JSON_HAS_RANGES && !defined(__MINGW32__)
+#if JSON_HAS_RANGE_VIEW_CONVERSION
 template < typename BasicJsonType, typename T,
            enable_if_t < is_compatible_range_view<std::remove_cvref_t<T>>::value
                          && !is_compatible_string_type<BasicJsonType, std::remove_cvref_t<T>>::value

include/nlohmann/detail/exceptions.hpp

@@ -286,6 +286,27 @@ class other_error : public exception
     other_error(int id_, const char* what_arg) : exception(id_, what_arg) {}
 };
 
+/*!
+@brief helper function to call JSON_THROW from a template
+@note JSON_THROW is a macro that, depending on the JSON_THROW_USER /
+      JSON_TRY_USER / JSON_NOEXCEPTION configuration, may expand to code
+      that does not reference its argument (e.g. `std::abort()`), which
+      would trigger a compilation error if the argument's type depends on
+      a template parameter that is otherwise unused. Wrapping the call in
+      a templated function avoids this and gives the compiler a single
+      place to see the (possibly unused) parameter.
+*/
+template<typename ExceptionType>
+void templated_json_throw(ExceptionType exception)
+{
+    JSON_THROW(exception);
+
+    // JSON_THROW may expand to code that discards its argument (e.g. when
+    // exceptions are disabled) - the cast below avoids an unused-parameter
+    // warning with -Werror in that case
+    (void)exception;
+}
+
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END
 

include/nlohmann/detail/input/binary_reader.hpp

@@ -31,7 +31,6 @@
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/is_sax.hpp>
 #include <nlohmann/detail/meta/type_traits.hpp>
-#include <nlohmann/detail/output/error_handler.hpp>
 #include <nlohmann/detail/string_concat.hpp>
 #include <nlohmann/detail/string_utils.hpp>
 #include <nlohmann/detail/value_t.hpp>
@@ -109,16 +108,8 @@ class binary_reader
     @brief create a binary reader
 
     @param[in] adapter  input adapter to read from
-    @param[in] format   the binary format to parse
-    @param[in] error_handler  how to treat text strings and object keys that
-               are not well-formed UTF-8; none of the supported formats
-               requires a decoder to reject those, so the default is to
-               @ref error_handler_t::keep them unchanged, as every binary
-               reader did before this parameter existed
     */
-    explicit binary_reader(InputAdapterType&& adapter, const input_format_t format = input_format_t::json,
+    explicit binary_reader(InputAdapterType&& adapter, const input_format_t format = input_format_t::json) noexcept : ia(std::move(adapter)), input_format(format)
-                           const error_handler_t error_handler = error_handler_t::keep) noexcept
-        : ia(std::move(adapter)), input_format(format), error_handler(error_handler)
     {
         (void)detail::is_sax_static_asserts<SAX, BasicJsonType> {};
     }
@@ -437,7 +428,7 @@ class binary_reader
     {
         if (get_bson_cstr_bulk(result, std::integral_constant<bool, bulk_scan> {}))
         {
-            return check_string_utf8(result, "key");
+            return true;
         }
 
         auto out = std::back_inserter(result);
@@ -450,7 +441,7 @@ class binary_reader
             }
             if (current == 0x00)
             {
-                return check_string_utf8(result, "key");
+                return true;
             }
             *out++ = static_cast<typename string_t::value_type>(current);
         }
@@ -531,7 +522,7 @@ class binary_reader
                                             "string"), nullptr));
         }
 
-        return check_string_utf8(result, "string");
+        return true;
     }
 
     /*!
@@ -1158,7 +1149,7 @@ class binary_reader
 
     @return whether string creation completed
     */
-    bool get_cbor_string(string_t& result, const char* context = "string")
+    bool get_cbor_string(string_t& result)
     {
         // number of indefinite-length strings that have been opened and not
         // closed yet. RFC 8949, Section 3.2.3 does not permit nesting them,
@@ -1188,7 +1179,7 @@ class binary_reader
             {
                 if (--open == 0)
                 {
-                    return check_string_utf8(result, context);
+                    return true;
                 }
                 get();
                 continue;
@@ -1201,7 +1192,7 @@ class binary_reader
 
             if (open == 0)
             {
-                return check_string_utf8(result, context);
+                return true;
             }
 
             get();
@@ -1225,7 +1216,7 @@ class binary_reader
         // EOF and major type 3 (text string) are left to get_cbor_string
         if (current == char_traits<char_type>::eof() || (static_cast<unsigned int>(current) & 0xE0u) == 0x60u)
         {
-            return get_cbor_string(result, "key");
+            return get_cbor_string(result);
         }
 
         const char* found = nullptr;
@@ -2013,7 +2004,7 @@ class binary_reader
 
     @return whether string creation completed
     */
-    bool get_msgpack_string(string_t& result, const char* context = "string")
+    bool get_msgpack_string(string_t& result)
     {
         if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::msgpack, "string")))
         {
@@ -2056,25 +2047,25 @@ class binary_reader
             case 0xBE:
             case 0xBF:
             {
-                return get_string(input_format_t::msgpack, static_cast<unsigned int>(current) & 0x1Fu, result) && check_string_utf8(result, context);
+                return get_string(input_format_t::msgpack, static_cast<unsigned int>(current) & 0x1Fu, result);
             }
 
             case 0xD9: // str 8
             {
                 std::uint8_t len{};
-                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result) && check_string_utf8(result, context);
+                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result);
             }
 
             case 0xDA: // str 16
             {
                 std::uint16_t len{};
-                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result) && check_string_utf8(result, context);
+                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result);
             }
 
             case 0xDB: // str 32
             {
                 std::uint32_t len{};
-                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result) && check_string_utf8(result, context);
+                return get_number(input_format_t::msgpack, len) && get_string(input_format_t::msgpack, len, result);
             }
 
             default:
@@ -2152,7 +2143,7 @@ class binary_reader
                 // byte 0xC1 are left to get_msgpack_string
                 if (current == char_traits<char_type>::eof())
                 {
-                    return get_msgpack_string(result, "key");
+                    return get_msgpack_string(result);
                 }
                 if (current <= 0x7F || current >= 0xE0)
                 {
@@ -2168,7 +2159,7 @@ class binary_reader
                 }
                 else
                 {
-                    return get_msgpack_string(result, "key");
+                    return get_msgpack_string(result);
                 }
                 break;
         }
@@ -2414,7 +2405,7 @@ class binary_reader
                         if (top.is_object)
                         {
                             key.clear();
-                            if (JSON_HEDLEY_UNLIKELY(!get_ubjson_string(key, true, "key") || !sax->key(key)))
+                            if (JSON_HEDLEY_UNLIKELY(!get_ubjson_string(key) || !sax->key(key)))
                             {
                                 return false;
                             }
@@ -2436,7 +2427,7 @@ class binary_reader
                     if (top.is_object)
                     {
                         key.clear();
-                        if (JSON_HEDLEY_UNLIKELY(!get_ubjson_string(key, false, "key") || !sax->key(key)))
+                        if (JSON_HEDLEY_UNLIKELY(!get_ubjson_string(key, false) || !sax->key(key)))
                         {
                             return false;
                         }
@@ -2504,7 +2495,7 @@ class binary_reader
 
     @return whether string creation completed
     */
-    bool get_ubjson_string(string_t& result, const bool get_char = true, const char* context = "string")
+    bool get_ubjson_string(string_t& result, const bool get_char = true)
     {
         if (get_char)
         {
@@ -2525,31 +2516,31 @@ class binary_reader
             case 'U':
             {
                 std::uint8_t len{};
-                return get_number(input_format, len) && get_string(input_format, len, result) && check_string_utf8(result, context);
+                return get_number(input_format, len) && get_string(input_format, len, result);
             }
 
             case 'i':
             {
                 std::int8_t len{};
-                return get_number(input_format, len) && check_ubjson_string_length(len) && get_string(input_format, len, result) && check_string_utf8(result, context);
+                return get_number(input_format, len) && check_ubjson_string_length(len) && get_string(input_format, len, result);
             }
 
             case 'I':
             {
                 std::int16_t len{};
-                return get_number(input_format, len) && check_ubjson_string_length(len) && get_string(input_format, len, result) && check_string_utf8(result, context);
+                return get_number(input_format, len) && check_ubjson_string_length(len) && get_string(input_format, len, result);
             }
 
             case 'l':
             {
                 std::int32_t len{};
-                return get_number(input_format, len) && check_ubjson_string_length(len) && get_string(input_format, len, result) && check_string_utf8(result, context);
+                return get_number(input_format, len) && check_ubjson_string_length(len) && get_string(input_format, len, result);
             }
 
             case 'L':
             {
                 std::int64_t len{};
-                return get_number(input_format, len) && check_ubjson_string_length(len) && get_string(input_format, len, result) && check_string_utf8(result, context);
+                return get_number(input_format, len) && check_ubjson_string_length(len) && get_string(input_format, len, result);
             }
 
             case 'u':
@@ -2559,7 +2550,7 @@ class binary_reader
                     break;
                 }
                 std::uint16_t len{};
-                return get_number(input_format, len) && get_string(input_format, len, result) && check_string_utf8(result, context);
+                return get_number(input_format, len) && get_string(input_format, len, result);
             }
 
             case 'm':
@@ -2569,7 +2560,7 @@ class binary_reader
                     break;
                 }
                 std::uint32_t len{};
-                return get_number(input_format, len) && get_string(input_format, len, result) && check_string_utf8(result, context);
+                return get_number(input_format, len) && get_string(input_format, len, result);
             }
 
             case 'M':
@@ -2579,7 +2570,7 @@ class binary_reader
                     break;
                 }
                 std::uint64_t len{};
-                return get_number(input_format, len) && get_string(input_format, len, result) && check_string_utf8(result, context);
+                return get_number(input_format, len) && get_string(input_format, len, result);
             }
 
             default:
@@ -4040,50 +4031,27 @@ class binary_reader
                     const NumberType len,
                     string_t& result)
     {
-        // Strings are taken as is by default: none of CBOR (RFC 8949 §3.1
+        // get_bytes() appends to result, and CBOR indefinite-length strings
-        // leaves the choice to the decoder), MessagePack (whose spec
+        // collect all their chunks in the same result; validating only the
-        // explicitly allows a str object to contain an invalid byte
+        // newly read bytes keeps the check linear in the input size
-        // sequence), UBJSON, BJData, or BSON requires a decoder to reject
+        const std::size_t old_size = result.size();
-        // ill-formed UTF-8. Checking (and, with @ref error_handler_t::strict,
+        if (JSON_HEDLEY_UNLIKELY(!get_bytes(format, len, "string", result)))
-        // rejecting, or with `replace`/`ignore`, sanitizing) is opt-in via
+        {
-        // @ref error_handler, applied once the whole string (all chunks of
+            return false;
-        // an indefinite-length CBOR string included) has been assembled, by
-        // @ref check_string_utf8 at the call site.
-        return get_bytes(format, len, "string", result);
         }
 
-    /*!
+        // RFC 8949 (CBOR) §3.1 and the MessagePack/BSON/UBJSON specifications
-    @brief validate a decoded text string (value or object key) against @ref error_handler
+        // all require text strings to be valid UTF-8; reject anything else
-
+        // right here so malformed input is caught at decode time instead of
-    None of the binary formats requires a decoder to reject ill-formed UTF-8
+        // only surfacing later as a type_error.316 when the value is dumped
-    in a text string (see @ref get_string), so by default
+        // (which would defeat allow_exceptions=false / strict discarding).
-    (@ref error_handler_t::keep) this does nothing. A stricter
+        if (JSON_HEDLEY_UNLIKELY(!is_valid_utf8(result, old_size)))
-    @ref error_handler opts into the same well-formedness check @ref
-    serializer::dump_escaped_impl applies when dumping a string:
-    @ref error_handler_t::strict rejects ill-formed input with
-    parse_error.113 (honoring `allow_exceptions` via @a sax), while
-    @ref error_handler_t::replace / @ref error_handler_t::ignore sanitize
-    @a result in place, using the exact same rules.
-
-    @param[in,out] result  the already assembled string to check
-    @param[in] context     further context information (for diagnostics)
-    @return whether @a result is acceptable (always true for `keep`)
-    */
-    bool check_string_utf8(string_t& result, const char* context)
         {
-        if (error_handler == error_handler_t::keep || is_valid_utf8(result))
+            return sax->parse_error(chars_read, get_token_string(),
-        {
+                                    parse_error::create(113, chars_read,
-            return true;
+                                            exception_message(format, "invalid string: ill-formed UTF-8 byte", "string"), nullptr));
         }
 
-        if (error_handler == error_handler_t::strict)
-        {
-            auto last_token = get_token_string();
-            return sax->parse_error(chars_read, last_token, parse_error::create(113, chars_read,
-                                    exception_message(input_format, "invalid string: ill-formed UTF-8 byte", context), nullptr));
-        }
-
-        result = sanitize_utf8(result, error_handler);
         return true;
     }
 
@@ -4258,9 +4226,6 @@ class binary_reader
     /// input format
     const input_format_t input_format = input_format_t::json;
 
-    /// how to treat text strings/object keys that are not well-formed UTF-8
-    const error_handler_t error_handler = error_handler_t::keep;
-
     /// the SAX parser
     json_sax_t* sax = nullptr;
 

include/nlohmann/detail/iterators/iter_impl.hpp

@@ -60,9 +60,11 @@ class iter_impl // NOLINT(cppcoreguidelines-special-member-functions,hicpp-speci
     static_assert(is_basic_json<typename std::remove_const<BasicJsonType>::type>::value,
                   "iter_impl only accepts (const) basic_json");
     // superficial check for the LegacyBidirectionalIterator named requirement
-    static_assert(std::is_base_of<std::bidirectional_iterator_tag, std::bidirectional_iterator_tag>::value
+    // note: only array_t::iterator is checked here; object_t::iterator may be
-                  &&  std::is_base_of<std::bidirectional_iterator_tag, typename std::iterator_traits<typename array_t::iterator>::iterator_category>::value,
+    // a forward-only iterator as long as reverse iteration and operator--
-                  "basic_json iterator assumes array and object type iterators satisfy the LegacyBidirectionalIterator named requirement.");
+    // are never used on it
+    static_assert(std::is_base_of<std::bidirectional_iterator_tag, typename std::iterator_traits<typename array_t::iterator>::iterator_category>::value,
+                  "basic_json iterator assumes array type iterators satisfy the LegacyBidirectionalIterator named requirement.");
 
   public:
     /// The std::iterator class template (used as a base class to provide typedefs) is deprecated in C++17.

include/nlohmann/detail/json_pointer.hpp

@@ -240,6 +240,72 @@ class json_pointer
     }
 
   private:
+    /*!
+    @brief result of @ref parse_array_index
+
+    @ref array_index maps each value to the corresponding parse_error/out_of_range
+    exception; @ref contains and @ref get_checked_or_null, which must not throw for
+    an out-of-range or unrepresentable index, switch on it directly instead.
+    */
+    enum class array_index_status
+    {
+        ok,                ///< @a s is a valid, representable array index
+        leading_zero,      ///< @a s begins with '0' but has more than one character
+        not_a_number,      ///< @a s does not begin with a digit
+        unresolved,        ///< @a s could not be converted to an integer
+        exceeds_size_type  ///< @a s converts to an integer that exceeds size_type
+    };
+
+    /*!
+    @param[in] s    reference token to be converted into an array index
+    @param[out] idx the integer representation of @a s if @ref array_index_status::ok
+                     is returned; left unchanged otherwise
+
+    @return whether @a s is a valid array index, and if not, why
+
+    @note this function never throws; @ref array_index and the callers that must not
+          throw (@ref contains, @ref get_checked_or_null) build on it instead of each
+          re-implementing the RFC 6901 digit rules and the @a size_type range check
+    */
+    template<typename BasicJsonType>
+    static array_index_status parse_array_index(const string_t& s, typename BasicJsonType::size_type& idx) noexcept
+    {
+        using size_type = typename BasicJsonType::size_type;
+
+        // error condition (cf. RFC 6901, Sect. 4)
+        if (JSON_HEDLEY_UNLIKELY(s.size() > 1 && s[0] == '0'))
+        {
+            return array_index_status::leading_zero;
+        }
+
+        // error condition (cf. RFC 6901, Sect. 4)
+        if (JSON_HEDLEY_UNLIKELY(s.size() > 1 && !(s[0] >= '1' && s[0] <= '9')))
+        {
+            return array_index_status::not_a_number;
+        }
+
+        const char* p = s.data();
+        char* p_end = nullptr; // NOLINT(misc-const-correctness)
+        errno = 0; // strtoull doesn't reset errno
+        const unsigned long long res = std::strtoull(p, &p_end, 10); // NOLINT(runtime/int)
+        if (p == p_end // invalid input or empty string
+                || errno == ERANGE // out of range
+                || JSON_HEDLEY_UNLIKELY(static_cast<std::size_t>(p_end - p) != s.size())) // incomplete read
+        {
+            return array_index_status::unresolved;
+        }
+
+        // the index does not fit into size_type; on 64-bit platforms this is
+        // only SIZE_MAX itself (see #2203 and #5395)
+        if (res >= static_cast<unsigned long long>((std::numeric_limits<size_type>::max)()))  // NOLINT(runtime/int)
+        {
+            return array_index_status::exceeds_size_type;
+        }
+
+        idx = static_cast<size_type>(res);
+        return array_index_status::ok;
+    }
+
     /*!
     @param[in] s  reference token to be converted into an array index
 
@@ -253,39 +319,23 @@ class json_pointer
     template<typename BasicJsonType>
     static typename BasicJsonType::size_type array_index(const string_t& s)
     {
-        using size_type = typename BasicJsonType::size_type;
+        typename BasicJsonType::size_type idx{};
-
+        switch (parse_array_index<BasicJsonType>(s, idx))
-        // error condition (cf. RFC 6901, Sect. 4)
-        if (JSON_HEDLEY_UNLIKELY(s.size() > 1 && s[0] == '0'))
         {
+            case array_index_status::leading_zero:
                 JSON_THROW(detail::parse_error::create(106, 0, detail::concat("array index '", s, "' must not begin with '0'"), nullptr));
-        }
+            case array_index_status::not_a_number:
-
-        // error condition (cf. RFC 6901, Sect. 4)
-        if (JSON_HEDLEY_UNLIKELY(s.size() > 1 && !(s[0] >= '1' && s[0] <= '9')))
-        {
                 JSON_THROW(detail::parse_error::create(109, 0, detail::concat("array index '", s, "' is not a number"), nullptr));
-        }
+            case array_index_status::unresolved:
-
-        const char* p = s.data();
-        char* p_end = nullptr; // NOLINT(misc-const-correctness)
-        errno = 0; // strtoull doesn't reset errno
-        const unsigned long long res = std::strtoull(p, &p_end, 10); // NOLINT(runtime/int)
-        if (p == p_end // invalid input or empty string
-                || errno == ERANGE // out of range
-                || JSON_HEDLEY_UNLIKELY(static_cast<std::size_t>(p_end - p) != s.size())) // incomplete read
-        {
                 JSON_THROW(detail::out_of_range::create(404, detail::concat("unresolved reference token '", s, "'"), nullptr));
-        }
+            case array_index_status::exceeds_size_type:
-
-        // the index does not fit into size_type; on 64-bit platforms this is
-        // only SIZE_MAX itself (see #2203 and #5395)
-        if (res >= static_cast<unsigned long long>((std::numeric_limits<size_type>::max)()))  // NOLINT(runtime/int)
-        {
                 JSON_THROW(detail::out_of_range::create(410, detail::concat("array index ", s, " exceeds size_type"), nullptr));
+            case array_index_status::ok:
+            default:
+                break;
         }
 
-        return static_cast<size_type>(res);
+        return idx;
     }
 
   JSON_PRIVATE_UNLESS_TESTED:
@@ -584,63 +634,6 @@ class json_pointer
         return *ptr;
     }
 
-    /*!
-    @throw parse_error.106   if an array index begins with '0'
-    @throw parse_error.109   if an array index was not a number
-    @throw out_of_range.402  if the array index '-' is used
-    @throw out_of_range.404  if the JSON pointer can not be resolved
-    */
-    template<typename BasicJsonType>
-    const BasicJsonType& get_checked(const BasicJsonType* ptr) const
-    {
-        for (const auto& reference_token : reference_tokens)
-        {
-            switch (ptr->type())
-            {
-                case detail::value_t::object:
-                {
-                    // note: at performs range check
-                    ptr = &ptr->at(reference_token);
-                    break;
-                }
-
-                case detail::value_t::array:
-                {
-                    if (JSON_HEDLEY_UNLIKELY(reference_token == "-"))
-                    {
-                        // "-" always fails the range check
-                        JSON_THROW(detail::out_of_range::create(402, detail::concat(
-                                "array index '-' (", std::to_string(ptr->m_data.m_value.array->size()),
-                                ") is out of range"), ptr));
-                    }
-
-                    const auto idx = array_index<BasicJsonType>(reference_token);
-                    // Bounds check before access to avoid exception with JSON_NOEXCEPTION
-                    if (JSON_HEDLEY_UNLIKELY(idx >= ptr->m_data.m_value.array->size()))
-                    {
-                        JSON_THROW(detail::out_of_range::create(401, detail::concat(
-                                "array index ", std::to_string(idx), " is out of range"), ptr));
-                    }
-                    ptr = &ptr->operator[](idx);
-                    break;
-                }
-
-                case detail::value_t::null:
-                case detail::value_t::string:
-                case detail::value_t::boolean:
-                case detail::value_t::number_integer:
-                case detail::value_t::number_unsigned:
-                case detail::value_t::number_float:
-                case detail::value_t::binary:
-                case detail::value_t::discarded:
-                default:
-                    JSON_THROW(detail::out_of_range::create(404, detail::concat("unresolved reference token '", reference_token, "'"), ptr));
-            }
-        }
-
-        return *ptr;
-    }
-
     /*!
     @brief return a pointer to the pointed to value, or `nullptr` if the
            pointer cannot be resolved because a key is missing, an array
@@ -679,18 +672,23 @@ class json_pointer
                         return nullptr;
                     }
 
-                    // may throw parse_error.106/109 for a malformed index; an
+                    // a malformed index throws parse_error.106/109; an
                     // index that is syntactically valid but cannot be
                     // represented (out_of_range.404/410) is treated like an
                     // out-of-range index below
                     typename BasicJsonType::size_type idx{};
-                    JSON_TRY
+                    switch (parse_array_index<BasicJsonType>(reference_token, idx))
-                    {
-                        idx = array_index<BasicJsonType>(reference_token);
-                    }
-                    JSON_INTERNAL_CATCH (detail::out_of_range&)
                     {
+                        case array_index_status::leading_zero:
+                            JSON_THROW(detail::parse_error::create(106, 0, detail::concat("array index '", reference_token, "' must not begin with '0'"), nullptr));
+                        case array_index_status::not_a_number:
+                            JSON_THROW(detail::parse_error::create(109, 0, detail::concat("array index '", reference_token, "' is not a number"), nullptr));
+                        case array_index_status::unresolved:
+                        case array_index_status::exceeds_size_type:
                             return nullptr;
+                        case array_index_status::ok:
+                        default:
+                            break;
                     }
 
                     if (JSON_HEDLEY_UNLIKELY(idx >= ptr->m_data.m_value.array->size()))
@@ -718,8 +716,8 @@ class json_pointer
     }
 
     /*!
-    @throw parse_error.106   if an array index begins with '0'
+    @note unlike array_index(), this never throws: a malformed or unrepresentable
-    @throw parse_error.109   if an array index was not a number
+          array index reference token is treated like a missing key (see #5395)
     */
     template<typename BasicJsonType>
     bool contains(const BasicJsonType* ptr) const
@@ -747,49 +745,17 @@ class json_pointer
                         // "-" always fails the range check
                         return false;
                     }
-                    if (JSON_HEDLEY_UNLIKELY(reference_token.empty()))
-                    {
-                        // an empty reference token is not an array index; array_index()
-                        // would throw out_of_range.404 -- contains() must not throw (see #5395)
-                        return false;
-                    }
-                    if (JSON_HEDLEY_UNLIKELY(reference_token.size() == 1 && !('0' <= reference_token[0] && reference_token[0] <= '9')))
-                    {
-                        // invalid char
-                        return false;
-                    }
-                    if (JSON_HEDLEY_UNLIKELY(reference_token.size() > 1))
-                    {
-                        if (JSON_HEDLEY_UNLIKELY(!('1' <= reference_token[0] && reference_token[0] <= '9')))
-                        {
-                            // the first char should be between '1' and '9'
-                            return false;
-                        }
-                        for (std::size_t i = 1; i < reference_token.size(); i++)
-                        {
-                            if (JSON_HEDLEY_UNLIKELY(!('0' <= reference_token[i] && reference_token[i] <= '9')))
-                            {
-                                // other char should be between '0' and '9'
-                                return false;
-                            }
-                        }
-                    }
 
-                    // the reference token consists only of digits at this point (cf. checks
+                    // any parse failure (malformed index, or one that is syntactically
-                    // above); however, its numeric value might not be representable, in which
+                    // valid but not representable as size_type) means the reference
-                    // case array_index() would throw out_of_range.404/410 -- contains() must
+                    // token cannot denote an existing array element -- contains() must
-                    // not throw (see #5395), so such a reference token is treated as "not found"
+                    // not throw (see #5395), so it is treated as "not found"
-                    errno = 0; // strtoull() does not reset errno on success
+                    typename BasicJsonType::size_type idx{};
-                    char* p_end = nullptr; // NOLINT(misc-const-correctness)
+                    if (JSON_HEDLEY_UNLIKELY(parse_array_index<BasicJsonType>(reference_token, idx) != array_index_status::ok))
-                    const unsigned long long magnitude = std::strtoull(reference_token.data(), &p_end, 10); // NOLINT(runtime/int)
-                    if (JSON_HEDLEY_UNLIKELY(errno == ERANGE // the value exceeds ULLONG_MAX
-                                             || magnitude >= static_cast<unsigned long long>((std::numeric_limits<typename BasicJsonType::size_type>::max)()))) // NOLINT(runtime/int)
                     {
-                        // the array index cannot be represented as size_type
                         return false;
                     }
 
-                    const auto idx = array_index<BasicJsonType>(reference_token);
                     if (idx >= ptr->size())
                     {
                         // index out of range

include/nlohmann/detail/macro_scope.hpp

@@ -9,7 +9,6 @@
 #pragma once
 
 #include <utility> // declval, pair
-#include <nlohmann/detail/meta/detected.hpp>
 #include <nlohmann/thirdparty/hedley/hedley.hpp>
 
 // This file contains all internal macro definitions (except those affecting ABI)
@@ -140,10 +139,12 @@
         // libstdc++ < 11 has incomplete C++20 ranges (issue #4440)
     #elif defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE < 11
         #define JSON_HAS_RANGES 0
-        // libc++ < 16 has incomplete C++20 ranges (issue #4440)
+        // clang < 16 with libstdc++ does not implement the ranges customization
+        // points libstdc++ declares, so its C++20 ranges support is incomplete (issue #5161)
     #elif defined(__clang__) && !defined(__apple_build_version__) \
         && __clang_major__ < 16 && defined(__GLIBCXX__)
         #define JSON_HAS_RANGES 0
+        // libc++ < 16 has incomplete C++20 ranges (issue #4440)
     #elif defined(_LIBCPP_VERSION) && _LIBCPP_VERSION < 160000
         #define JSON_HAS_RANGES 0
         // nvcc CUDA 12.0/12.1 chokes on the enable_borrowed_range variable-template
@@ -158,6 +159,18 @@
     #endif
 #endif
 
+// std::ranges view conversion (to_json/is_compatible_array_type_impl) additionally
+// needs to be disabled on MinGW, whose std::ranges support is incomplete
+// (issue #4916); this macro combines both conditions so the check and its
+// reason are not duplicated at every use site.
+#ifndef JSON_HAS_RANGE_VIEW_CONVERSION
+    #if JSON_HAS_RANGES && !defined(__MINGW32__)
+        #define JSON_HAS_RANGE_VIEW_CONVERSION 1
+    #else
+        #define JSON_HAS_RANGE_VIEW_CONVERSION 0
+    #endif
+#endif
+
 #ifndef JSON_HAS_STD_FORMAT
     #if defined(JSON_HAS_CPP_20) && defined(__cpp_lib_format)
         #define JSON_HAS_STD_FORMAT 1
@@ -279,26 +292,11 @@
 
 
 
-/*!
-@brief function to wrap JSON_THROW_MACRO - there can be compilation errors about
-       there being no arguments to JSON_THROW that depend on template arguments
-       if this is not used to call JSON_THROW
-*/
-template<typename ExceptionType>
-void templated_json_throw(ExceptionType exception)
-{
-    JSON_THROW(exception);
-
-    /* JSON_THROW(exception) discards exception and aborts - void cast needed to supress
-       compilation error if compiled with -Werror and Wunused-parameter */
-    (void)exception;
-}
-
 /*!
 @brief macro to briefly define a mapping between an enum and JSON with exception
        on invalid input
 @def NLOHMANN_JSON_SERIALIZE_ENUM_STRICT
-@since version 3.12.0
+@since version 3.13.0
 */
 #define NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(ENUM_TYPE, ...)                                     \
     template<typename BasicJsonType>                                                            \
@@ -314,7 +312,7 @@ void templated_json_throw(ExceptionType exception)
             return ej_pair.first == e;                                                          \
         });                                                                                     \
         if (it != std::end(m)) j = it->second;                                                  \
-        else templated_json_throw<nlohmann::detail::out_of_range>(nlohmann::detail::out_of_range::create(410,"enum value out of range for " #ENUM_TYPE, nullptr)); \
+        else ::nlohmann::detail::templated_json_throw<nlohmann::detail::out_of_range>(nlohmann::detail::out_of_range::create(410,"enum value out of range for " #ENUM_TYPE, nullptr)); \
     }                                                                                           \
     template<typename BasicJsonType>                                                            \
     inline void from_json(const BasicJsonType& j, ENUM_TYPE& e)                                 \
@@ -329,7 +327,7 @@ void templated_json_throw(ExceptionType exception)
             return ej_pair.second == j;                                                         \
         });                                                                                     \
         if (it != std::end(m)) e = it->first;                                                   \
-        else templated_json_throw<nlohmann::detail::out_of_range>(nlohmann::detail::out_of_range::create(410, nlohmann::detail::concat("enum value out of range for " #ENUM_TYPE ": ", j.dump(-1, ' ', false, nlohmann::detail::error_handler_t::replace)), &j)); \
+        else ::nlohmann::detail::templated_json_throw<nlohmann::detail::out_of_range>(nlohmann::detail::out_of_range::create(410, nlohmann::detail::concat("enum value out of range for " #ENUM_TYPE ": ", j.dump(-1, ' ', false, nlohmann::detail::error_handler_t::replace)), &j)); \
     }
 
 // Ugly macros to avoid uglier copy-paste when specializing basic_json. They
@@ -874,30 +872,6 @@ void templated_json_throw(ExceptionType exception)
     \
     template<typename... T>                                                       \
     using result_of_##std_name = decltype(std_name(std::declval<T>()...));        \
-    }                                                                             \
-    \
-    namespace detail2 {                                                           \
-    struct std_name##_tag                                                         \
-    {                                                                             \
-    };                                                                            \
-    \
-    template<typename... T>                                                       \
-    std_name##_tag std_name(T&&...);                                              \
-    \
-    template<typename... T>                                                       \
-    using result_of_##std_name = decltype(std_name(std::declval<T>()...));        \
-    \
-    template<typename... T>                                                       \
-    struct would_call_std_##std_name                                              \
-    {                                                                             \
-        static constexpr auto const value = ::nlohmann::detail::                  \
-                                            is_detected_exact<std_name##_tag, result_of_##std_name, T...>::value; \
-    };                                                                            \
-    } /* namespace detail2 */ \
-    \
-    template<typename... T>                                                       \
-    struct would_call_std_##std_name : detail2::would_call_std_##std_name<T...>   \
-    {                                                                             \
     }
 
 #ifndef JSON_USE_IMPLICIT_CONVERSIONS

include/nlohmann/detail/macro_unscope.hpp

@@ -35,13 +35,13 @@
     #undef JSON_HAS_EXPERIMENTAL_FILESYSTEM
     #undef JSON_HAS_THREE_WAY_COMPARISON
     #undef JSON_HAS_RANGES
+    #undef JSON_HAS_RANGE_VIEW_CONVERSION
     #undef JSON_HAS_STD_FORMAT
     #undef JSON_HAS_STATIC_RTTI
     #undef JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
     #undef JSON_BRACE_INIT_COPY_SEMANTICS
     #undef JSON_PRECISE_STREAM_POSITION
     #undef JSON_STRICT_NUL_HANDLING
-    #undef JSON_STRICT_BINARY_UTF8
 #endif
 
 #include <nlohmann/thirdparty/hedley/hedley_undef.hpp>

include/nlohmann/detail/meta/call_std/begin.hpp

@@ -12,6 +12,6 @@
 
 NLOHMANN_JSON_NAMESPACE_BEGIN
 
-NLOHMANN_CAN_CALL_STD_FUNC_IMPL(begin);
+NLOHMANN_CAN_CALL_STD_FUNC_IMPL(begin)
 
 NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/meta/call_std/end.hpp

@@ -12,6 +12,6 @@
 
 NLOHMANN_JSON_NAMESPACE_BEGIN
 
-NLOHMANN_CAN_CALL_STD_FUNC_IMPL(end);
+NLOHMANN_CAN_CALL_STD_FUNC_IMPL(end)
 
 NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/meta/detected.hpp

@@ -62,9 +62,5 @@ using detected_or_t = typename detected_or<Default, Op, Args...>::type;
 template<class Expected, template<class...> class Op, class... Args>
 using is_detected_exact = std::is_same<Expected, detected_t<Op, Args...>>;
 
-template<class To, template<class...> class Op, class... Args>
-using is_detected_convertible =
-    std::is_convertible<detected_t<Op, Args...>, To>;
-
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/meta/is_sax.hpp

@@ -8,7 +8,7 @@
 
 #pragma once
 
-#include <cstdint> // size_t
+#include <cstddef> // size_t
 #include <utility> // declval
 #include <string> // string
 
@@ -70,37 +70,6 @@ using parse_error_function_t = decltype(std::declval<T&>().parse_error(
         std::declval<std::size_t>(), std::declval<const std::string&>(),
         std::declval<const Exception&>()));
 
-template<typename SAX, typename BasicJsonType>
-struct is_sax
-{
-  private:
-    static_assert(is_basic_json<BasicJsonType>::value,
-                  "BasicJsonType must be of type basic_json<...>");
-
-    using number_integer_t = typename BasicJsonType::number_integer_t;
-    using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
-    using number_float_t = typename BasicJsonType::number_float_t;
-    using string_t = typename BasicJsonType::string_t;
-    using binary_t = typename BasicJsonType::binary_t;
-    using exception_t = typename BasicJsonType::exception;
-
-  public:
-    static constexpr bool value =
-        is_detected_exact<bool, null_function_t, SAX>::value &&
-        is_detected_exact<bool, boolean_function_t, SAX>::value &&
-        is_detected_exact<bool, number_integer_function_t, SAX, number_integer_t>::value &&
-        is_detected_exact<bool, number_unsigned_function_t, SAX, number_unsigned_t>::value &&
-        is_detected_exact<bool, number_float_function_t, SAX, number_float_t, string_t>::value &&
-        is_detected_exact<bool, string_function_t, SAX, string_t>::value &&
-        is_detected_exact<bool, binary_function_t, SAX, binary_t>::value &&
-        is_detected_exact<bool, start_object_function_t, SAX>::value &&
-        is_detected_exact<bool, key_function_t, SAX, string_t>::value &&
-        is_detected_exact<bool, end_object_function_t, SAX>::value &&
-        is_detected_exact<bool, start_array_function_t, SAX>::value &&
-        is_detected_exact<bool, end_array_function_t, SAX>::value &&
-        is_detected_exact<bool, parse_error_function_t, SAX, exception_t>::value;
-};
-
 template<typename SAX, typename BasicJsonType>
 struct is_sax_static_asserts
 {
@@ -120,8 +89,6 @@ struct is_sax_static_asserts
                   "Missing/invalid function: bool null()");
     static_assert(is_detected_exact<bool, boolean_function_t, SAX>::value,
                   "Missing/invalid function: bool boolean(bool)");
-    static_assert(is_detected_exact<bool, boolean_function_t, SAX>::value,
-                  "Missing/invalid function: bool boolean(bool)");
     static_assert(
         is_detected_exact<bool, number_integer_function_t, SAX,
         number_integer_t>::value,

include/nlohmann/detail/meta/logic.hpp

@@ -1,54 +0,0 @@
-#pragma once
-
-#include <nlohmann/detail/macro_scope.hpp>
-
-NLOHMANN_JSON_NAMESPACE_BEGIN
-namespace detail
-{
-#ifdef JSON_HAS_CPP_17
-
-template<bool... Booleans>
-struct cxpr_or_impl : std::integral_constant < bool, (Booleans || ...) > {};
-
-template<bool... Booleans>
-struct cxpr_and_impl : std::integral_constant < bool, (Booleans &&...) > {};
-
-#else
-
-template<bool... Booleans>
-struct cxpr_or_impl : std::false_type {};
-
-template<bool... Booleans>
-struct cxpr_or_impl<true, Booleans...> : std::true_type {};
-
-template<bool... Booleans>
-struct cxpr_or_impl<false, Booleans...> : cxpr_or_impl<Booleans...> {};
-
-template<bool... Booleans>
-struct cxpr_and_impl : std::true_type {};
-
-template<bool... Booleans>
-struct cxpr_and_impl<true, Booleans...> : cxpr_and_impl<Booleans...> {};
-
-template<bool... Booleans>
-struct cxpr_and_impl<false, Booleans...> : std::false_type {};
-
-#endif
-
-template<class Boolean>
-struct cxpr_not : std::integral_constant < bool, !Boolean::value > {};
-
-template<class... Booleans>
-struct cxpr_or : cxpr_or_impl<Booleans::value...> {};
-
-template<bool... Booleans>
-struct cxpr_or_c : cxpr_or_impl<Booleans...> {};
-
-template<class... Booleans>
-struct cxpr_and : cxpr_and_impl<Booleans::value...> {};
-
-template<bool... Booleans>
-struct cxpr_and_c : cxpr_and_impl<Booleans...> {};
-
-}  // namespace detail
-NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/meta/type_traits.hpp

@@ -283,6 +283,13 @@ template<class B, class... Bn>
 struct conjunction<B, Bn...>
 : std::conditional<static_cast<bool>(B::value), conjunction<Bn...>, B>::type {};
 
+// https://en.cppreference.com/w/cpp/types/disjunction
+template<class...> struct disjunction : std::false_type { };
+template<class B> struct disjunction<B> : B { };
+template<class B, class... Bn>
+struct disjunction<B, Bn...>
+: std::conditional<static_cast<bool>(B::value), B, disjunction<Bn...>>::type {};
+
 // https://en.cppreference.com/w/cpp/types/negation
 template<class B> struct negation : std::integral_constant < bool, !B::value > { };
 
@@ -477,9 +484,7 @@ template<typename T> struct is_range_view_optional_type<std::optional<T>> : std:
 template<typename T> struct is_range_view_optional_type : std::false_type {};
 #endif
 
-// std::ranges does not work properly on MinGW due to incomplete C++20 support
+#if JSON_HAS_RANGE_VIEW_CONVERSION
-// see https://github.com/nlohmann/json/issues/4916
-#if JSON_HAS_RANGES && !defined(__MINGW32__)
 
 // SafeToCheck guards against types that trigger circular constraints when
 // std::ranges::view<T> is evaluated on GCC 12 / libstdc++ 12:
@@ -518,7 +523,7 @@ struct is_compatible_array_type_impl <
 // filter_view) can match BOTH this iterator-based specialization AND the view-based one
 // below, causing ambiguity. Exclude views here so the two specializations are mutually
 // exclusive: this one handles plain iterable containers, the other handles views.
-#if JSON_HAS_RANGES && !defined(__MINGW32__)
+#if JSON_HAS_RANGE_VIEW_CONVERSION
 && !is_compatible_range_view<CompatibleArrayType>::value
 #endif
             >>
@@ -528,7 +533,7 @@ struct is_compatible_array_type_impl <
         range_value_t<CompatibleArrayType>>::value;
 };
 
-#if JSON_HAS_RANGES && !defined(__MINGW32__)
+#if JSON_HAS_RANGE_VIEW_CONVERSION
 template<typename BasicJsonType, typename CompatibleArrayType>
 struct is_compatible_array_type_impl <
     BasicJsonType, CompatibleArrayType,
@@ -604,7 +609,6 @@ struct is_compatible_integer_type_impl <
     std::is_integral<CompatibleNumberIntegerType>::value&&
     !std::is_same<bool, CompatibleNumberIntegerType>::value >>
 {
-    // is there an assert somewhere on overflows?
     using RealLimits = std::numeric_limits<RealIntegerType>;
     using CompatibleLimits = std::numeric_limits<CompatibleNumberIntegerType>;
 
@@ -810,20 +814,7 @@ struct has_capacity : std::integral_constant<bool, is_detected<detect_capacity,
 // a naive helper to check if a type is an ordered_map (exploits the fact that
 // ordered_map inherits capacity() from std::vector)
 template <typename T>
-struct is_ordered_map
+struct is_ordered_map : has_capacity<T> {};
-{
-    using one = char;
-
-    struct two
-    {
-        char x[2]; // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
-    };
-
-    template <typename C> static one test( decltype(&C::capacity) ) ;
-    template <typename C> static two test(...);
-
-    enum { value = sizeof(test<T>(nullptr)) == sizeof(char) }; // NOLINT(cppcoreguidelines-pro-type-vararg,hicpp-vararg,cppcoreguidelines-use-enum-class)
-};
 
 // to avoid useless casts (see https://github.com/nlohmann/json/issues/2893#issuecomment-889152324)
 template < typename T, typename U, enable_if_t < !std::is_same<T, U>::value, int > = 0 >
@@ -847,10 +838,8 @@ using all_signed = conjunction<std::is_signed<Types>...>;
 template<typename... Types>
 using all_unsigned = conjunction<std::is_unsigned<Types>...>;
 
-// there's a disjunction trait in another PR; replace when merged
 template<typename... Types>
-using same_sign = std::integral_constant < bool,
+using same_sign = disjunction<all_signed<Types...>, all_unsigned<Types...>>;
-      all_signed<Types...>::value || all_unsigned<Types...>::value >;
 
 template<typename OfType, typename T>
 using never_out_of_range = std::integral_constant < bool,

include/nlohmann/detail/output/binary_writer.hpp

@@ -26,7 +26,6 @@
 #include <nlohmann/detail/input/binary_reader.hpp>
 #include <nlohmann/detail/input/string_scan.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
-#include <nlohmann/detail/output/error_handler.hpp>
 #include <nlohmann/detail/output/output_adapters.hpp>
 #include <nlohmann/detail/string_concat.hpp>
 #include <nlohmann/detail/string_utils.hpp>
@@ -94,12 +93,8 @@ class binary_writer
     @param[in] sink  output sink to write to (a value-type sink such as
                      output_vector_sink, or output_adapter_sink wrapping a
                      type-erased output adapter)
-    @param[in] error_handler_  how to treat a string value or object key that
-               is not valid UTF-8 (CBOR, MessagePack, UBJSON, BJData, and BSON;
-               never consulted by @ref write_bon8)
     */
-    explicit binary_writer(OutputSinkType sink, const error_handler_t error_handler_ = binary_writer_default_error_handler())
+    explicit binary_writer(OutputSinkType sink) : oa(std::move(sink))
-        : oa(std::move(sink)), error_handler(error_handler_)
     {}
 
     /*!
@@ -112,20 +107,14 @@ class binary_writer
     from one.
 
     @param[in] adapter  output adapter to write to
-    @param[in] error_handler_  how to treat a string value or object key that
-               is not valid UTF-8 (CBOR, MessagePack, UBJSON, BJData, and BSON;
-               never consulted by @ref write_bon8)
     */
     template < typename SinkType = OutputSinkType,
                typename std::enable_if < std::is_constructible<SinkType, output_adapter_t<CharType>>::value, int >::type = 0 >
-    explicit binary_writer(output_adapter_t<CharType> adapter, const error_handler_t error_handler_ = binary_writer_default_error_handler())
+    explicit binary_writer(output_adapter_t<CharType> adapter) : oa(SinkType(std::move(adapter)))
-        : oa(SinkType(std::move(adapter))), error_handler(error_handler_)
     {}
 
     /*!
     @param[in] j  JSON value to serialize
-    @throw type_error.316 if a string value or an object key is not valid
-           UTF-8
     @throw type_error.317 if @a j is not an object
     */
     void write_bson(const BasicJsonType& j)
@@ -156,8 +145,6 @@ class binary_writer
 
     /*!
     @param[in] j  JSON value to serialize
-    @throw type_error.316 if a string value or an object key is not valid
-           UTF-8
     */
     void write_cbor(const BasicJsonType& j)
     {
@@ -224,16 +211,13 @@ class binary_writer
 
             case value_t::string:
             {
-                string_t storage;
-                const string_t& value = sanitize_utf8_for_write(*j.m_data.m_value.string, j, storage);
-
                 // step 1: write control byte and the string length
-                write_cbor_head(0x60, value.size());
+                write_cbor_head(0x60, j.m_data.m_value.string->size());
 
                 // step 2: write the string
                 oa.write_characters(
-                      reinterpret_cast<const CharType*>(value.data()),
+                      reinterpret_cast<const CharType*>(j.m_data.m_value.string->data()),
-                      value.size());
+                      j.m_data.m_value.string->size());
                 break;
             }
 
@@ -303,17 +287,6 @@ class binary_writer
                 // step 2: write each element
                 for (const auto& el : *j.m_data.m_value.object)
                 {
-                    // el.first is checked here, against the object as
-                    // diagnostics context, because write_cbor(el.first)
-                    // converts it to a temporary basic_json that would be
-                    // used as the context instead; for error_handler_t::keep
-                    // and ::replace/::ignore the recursive write_cbor(el.first)
-                    // call below handles the key like any other string, so no
-                    // separate check is needed here for those
-                    if (error_handler == error_handler_t::strict)
-                    {
-                        check_utf8(el.first, j);
-                    }
                     write_cbor(el.first);
                     write_cbor(el.second);
                 }
@@ -461,11 +434,8 @@ class binary_writer
 
             case value_t::string:
             {
-                string_t storage;
-                const string_t& value = sanitize_utf8_for_write(*j.m_data.m_value.string, j, storage);
-
                 // step 1: write control byte and the string length
-                const auto N = to_msgpack_length(value.size(), j);
+                const auto N = to_msgpack_length(j.m_data.m_value.string->size(), j);
                 if (N <= 31)
                 {
                     // fixstr
@@ -492,8 +462,8 @@ class binary_writer
 
                 // step 2: write the string
                 oa.write_characters(
-                      reinterpret_cast<const CharType*>(value.data()),
+                      reinterpret_cast<const CharType*>(j.m_data.m_value.string->data()),
-                      value.size());
+                      j.m_data.m_value.string->size());
                 break;
             }
 
@@ -640,13 +610,6 @@ class binary_writer
                 // step 2: write each element
                 for (const auto& el : *j.m_data.m_value.object)
                 {
-                    // as in write_cbor, el.first is checked here against the
-                    // object as diagnostics context; the recursive call below
-                    // handles keep/replace/ignore like any other string
-                    if (error_handler == error_handler_t::strict)
-                    {
-                        check_utf8(el.first, j);
-                    }
                     write_msgpack(el.first);
                     write_msgpack(el.second);
                 }
@@ -666,8 +629,6 @@ class binary_writer
     @param[in] add_prefix  whether prefixes need to be used for this value
     @param[in] use_bjdata  whether write in BJData format, default is false
     @param[in] bjdata_version  which BJData version to use, default is draft2
-    @throw type_error.316 if a string value or an object key is not valid
-           UTF-8
     */
     void write_ubjson(const BasicJsonType& j, const bool use_count,
                       const bool use_type, const bool add_prefix = true,
@@ -717,17 +678,14 @@ class binary_writer
 
             case value_t::string:
             {
-                string_t storage;
-                const string_t& value = sanitize_utf8_for_write(*j.m_data.m_value.string, j, storage);
-
                 if (add_prefix)
                 {
                     oa.write_character(to_char_type('S'));
                 }
-                write_number_with_ubjson_prefix(value.size(), true, use_bjdata);
+                write_number_with_ubjson_prefix(j.m_data.m_value.string->size(), true, use_bjdata);
                 oa.write_characters(
-                      reinterpret_cast<const CharType*>(value.data()),
+                      reinterpret_cast<const CharType*>(j.m_data.m_value.string->data()),
-                      value.size());
+                      j.m_data.m_value.string->size());
                 break;
             }
 
@@ -882,12 +840,10 @@ class binary_writer
 
                 for (const auto& el : *j.m_data.m_value.object)
                 {
-                    string_t storage;
+                    write_number_with_ubjson_prefix(el.first.size(), true, use_bjdata);
-                    const string_t& key = sanitize_utf8_for_write(el.first, j, storage);
-                    write_number_with_ubjson_prefix(key.size(), true, use_bjdata);
                     oa.write_characters(
-                          reinterpret_cast<const CharType*>(key.data()),
+                          reinterpret_cast<const CharType*>(el.first.data()),
-                          key.size());
+                          el.first.size());
                     write_ubjson(el.second, use_count, use_type, prefix_required, use_bjdata, bjdata_version);
                 }
 
@@ -928,12 +884,8 @@ class binary_writer
     /*!
     @return The size of a BSON document entry header, including the id marker
             and the entry name size (and its null-terminator).
-    @throw out_of_range.409 if @a name contains U+0000, before anything is
-           written
-    @throw type_error.316 if @a name is not valid UTF-8, before anything is
-           written
     */
-    std::size_t calc_bson_entry_header_size(const string_t& name, const BasicJsonType& j)
+    static std::size_t calc_bson_entry_header_size(const string_t& name, const BasicJsonType& j)
     {
         const auto it = name.find(static_cast<typename string_t::value_type>(0));
         if (JSON_HEDLEY_UNLIKELY(it != BasicJsonType::string_t::npos))
@@ -941,10 +893,8 @@ class binary_writer
             JSON_THROW(out_of_range::create(409, concat("BSON key cannot contain code point U+0000 (at byte ", std::to_string(it), ")"), &j));
         }
 
-        string_t storage;
+        static_cast<void>(j);
-        const string_t& sanitized = sanitize_utf8_for_write(name, j, storage);
+        return /*id*/ 1ul + name.size() + /*zero-terminator*/1u;
-
-        return /*id*/ 1ul + sanitized.size() + /*zero-terminator*/1u;
     }
 
     /*!
@@ -964,28 +914,14 @@ class binary_writer
 
     /*!
     @brief Writes the given @a element_type and @a name to the output adapter
-
-    @a name has already been validated (and, for @ref error_handler_t::strict,
-    found well-formed) by @ref calc_bson_entry_header_size during the earlier
-    size pass, so only @ref error_handler_t::replace / @ref
-    error_handler_t::ignore need to sanitize it again here, to actually write
-    the bytes that size was computed from.
     */
     void write_bson_entry_header(const string_t& name,
                                  const std::uint8_t element_type)
     {
         oa.write_character(to_char_type(element_type));
-
+        oa.write_characters(
-        if (error_handler == error_handler_t::keep || error_handler == error_handler_t::strict || is_valid_utf8(name))
+              reinterpret_cast<const CharType*>(name.data()),
-        {
+              name.size());
-            oa.write_characters(reinterpret_cast<const CharType*>(name.data()), name.size());
-        }
-        else
-        {
-            const string_t sanitized = sanitize_utf8(name, error_handler);
-            oa.write_characters(reinterpret_cast<const CharType*>(sanitized.data()), sanitized.size());
-        }
-
         // the terminating null byte is written explicitly rather than taken
         // from the buffer, so that string_t::data() need not be null-terminated
         oa.write_character(to_char_type(0x00));
@@ -1013,50 +949,24 @@ class binary_writer
 
     /*!
     @return The size of the BSON-encoded string in @a value
-    @throw type_error.316 if @a value is not valid UTF-8, before anything is
-           written
-
-    @note The UTF-8 check is skipped if @a value is already too long for the
-          32-bit BSON length field (@ref to_bson_length rejects it later, once
-          the size of the whole document is known); this also keeps the check
-          from reading past a StringType that reports a size larger than what
-          it actually holds.
     */
-    std::size_t calc_bson_string_size(const string_t& value, const BasicJsonType& j)
+    static std::size_t calc_bson_string_size(const string_t& value)
     {
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<std::int32_t>(value.size())))
-        {
-            string_t storage;
-            const string_t& sanitized = sanitize_utf8_for_write(value, j, storage);
-            return sizeof(std::int32_t) + sanitized.size() + 1ul;
-        }
         return sizeof(std::int32_t) + value.size() + 1ul;
     }
 
     /*!
     @brief Writes a BSON element with key @a name and string value @a value
-
-    @a value has already been validated (and, for @ref error_handler_t::strict,
-    found well-formed) by @ref calc_bson_string_size during the earlier size
-    pass, so only @ref error_handler_t::replace / @ref error_handler_t::ignore
-    need to sanitize it again here, to actually write the bytes that size was
-    computed from.
     */
     void write_bson_string(const string_t& name,
                            const string_t& value)
     {
         write_bson_entry_header(name, 0x02);
 
-        const bool sanitize = error_handler != error_handler_t::keep
+        write_number<std::int32_t>(to_bson_length(value.size() + 1ul), true);
-                              && error_handler != error_handler_t::strict
-                              && !is_valid_utf8(value);
-        const string_t sanitized = sanitize ? sanitize_utf8(value, error_handler) : string_t{};
-        const string_t& written = sanitize ? sanitized : value;
-
-        write_number<std::int32_t>(to_bson_length(written.size() + 1ul), true);
         oa.write_characters(
-              reinterpret_cast<const CharType*>(written.data()),
+              reinterpret_cast<const CharType*>(value.data()),
-              written.size());
+              value.size());
         // the terminating null byte is written explicitly rather than taken
         // from the buffer, so that string_t::data() need not be null-terminated
         oa.write_character(to_char_type(0x00));
@@ -1170,10 +1080,8 @@ class binary_writer
             is neither an object nor an array
     @throw out_of_range.415 if @a j is binary with a subtype that does not fit
            into a byte, before anything is written
-    @throw type_error.316 if @a j is a string that is not valid UTF-8, before
-           anything is written
     */
-    std::size_t calc_bson_value_size(const BasicJsonType& j)
+    static std::size_t calc_bson_value_size(const BasicJsonType& j)
     {
         switch (j.type())
         {
@@ -1193,7 +1101,7 @@ class binary_writer
                 return calc_bson_unsigned_size(j.m_data.m_value.number_unsigned);
 
             case value_t::string:
-                return calc_bson_string_size(*j.m_data.m_value.string, j);
+                return calc_bson_string_size(*j.m_data.m_value.string);
 
             case value_t::null:
                 return 0ul;
@@ -1306,10 +1214,8 @@ class binary_writer
            written
     @throw out_of_range.415 if a binary value's subtype does not fit into a
            byte, before anything is written
-    @throw type_error.316 if a string value or a key is not valid UTF-8,
-           before anything is written
     */
-    std::size_t calc_bson_sizes(const BasicJsonType& document, std::vector<std::size_t>& nested_sizes)
+    static std::size_t calc_bson_sizes(const BasicJsonType& document, std::vector<std::size_t>& nested_sizes)
     {
         // the object or array whose entries are being sized, and the ones it
         // is in; nothing is allocated unless the document nests
@@ -2186,7 +2092,7 @@ class binary_writer
     */
     void write_bon8_string(const string_t& s, bool& string_open, const BasicJsonType& context)
     {
-        check_utf8(s, context);
+        check_bon8_utf8(s, context);
 
         // a string that follows another string terminates it
         if (string_open)
@@ -2216,7 +2122,7 @@ class binary_writer
     @throw type_error.316 if @a s is not valid UTF-8; the message names the
            first byte of the first invalid or incomplete sequence
     */
-    static void check_utf8(const string_t& s, const BasicJsonType& context)
+    static void check_bon8_utf8(const string_t& s, const BasicJsonType& context)
     {
         static_cast<void>(context); // only used when exceptions are enabled
         const auto* data = reinterpret_cast<const unsigned char*>(s.data());
@@ -2227,57 +2133,6 @@ class binary_writer
         }
     }
 
-    /*!
-    @brief return @a s as it should be written, honoring @ref error_handler
-
-    Used by @ref write_cbor, @ref write_msgpack, @ref write_ubjson (and so
-    @ref write_bjdata), and the BSON writing functions for string values and
-    object keys; never by @ref write_bon8, which always validates, since UTF-8
-    lead bytes are structural there.
-
-    - @ref error_handler_t::keep: @a s is returned unchanged, without even
-      checking it (the behavior of release 3.12.0 and earlier).
-    - @ref error_handler_t::strict: @ref check_utf8 is called, which throws
-      type_error.316 if @a s is not valid UTF-8.
-    - @ref error_handler_t::replace / @ref error_handler_t::ignore: @a s is
-      sanitized into @a storage with exactly the rules @ref
-      serializer::dump_escaped_impl uses, so that parsing what @ref
-      basic_json::dump produces for the same string and the same handler
-      yields the same result.
-
-    Well-formed input is never copied: this returns a reference to @a s
-    itself in every case but a sanitized `replace`/`ignore` one, so @a
-    storage must outlive the returned reference only then.
-
-    @param[in] s        the string (value or object key) to write
-    @param[in] context  the value @a s belongs to (for diagnostics)
-    @param[out] storage  backing storage for a sanitized copy
-
-    @return a reference to @a s, or to @a storage once it holds a sanitized copy
-    */
-    const string_t& sanitize_utf8_for_write(const string_t& s, const BasicJsonType& context, string_t& storage) const
-    {
-        switch (error_handler)
-        {
-            case error_handler_t::keep:
-                return s;
-
-            case error_handler_t::strict:
-                check_utf8(s, context);
-                return s;
-
-            case error_handler_t::replace:
-            case error_handler_t::ignore:
-            default:
-                if (is_valid_utf8(s))
-                {
-                    return s;
-                }
-                storage = sanitize_utf8(s, error_handler);
-                return storage;
-        }
-    }
-
     /*!
     @brief write an integer in the shortest encoding
 
@@ -2606,10 +2461,6 @@ class binary_writer
 
     /// the output
     OutputSinkType oa;
-
-    /// how to treat a string value or object key that is not valid UTF-8
-    /// (CBOR, MessagePack, UBJSON, BJData, and BSON; not BON8)
-    const error_handler_t error_handler = binary_writer_default_error_handler();
 };
 
 }  // namespace detail

include/nlohmann/detail/output/error_handler.hpp

@@ -1,50 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#pragma once
-
-#include <nlohmann/detail/abi_macros.hpp>
-
-NLOHMANN_JSON_NAMESPACE_BEGIN
-namespace detail
-{
-
-/// how to treat decoding errors
-///
-/// @ref basic_json::dump uses this to decide what to do with ill-formed
-/// UTF-8 while escaping a string, and the binary writers (@ref
-/// basic_json::to_cbor, @ref basic_json::to_ubjson, @ref
-/// basic_json::to_bjdata, @ref basic_json::to_bson) use it the same way for
-/// string values and object keys. The binary readers (@ref
-/// basic_json::from_cbor, @ref basic_json::from_msgpack, @ref
-/// basic_json::from_ubjson, @ref basic_json::from_bjdata, @ref
-/// basic_json::from_bson) use it to decide whether to check text strings
-/// and object keys for well-formed UTF-8 at all, since none of those
-/// formats requires a decoder to do so.
-enum class error_handler_t
-{
-    strict,  ///< throw a type_error/parse_error exception in case of invalid UTF-8
-    replace, ///< replace invalid UTF-8 sequences with U+FFFD
-    ignore,  ///< ignore invalid UTF-8 sequences
-    keep     ///< keep invalid UTF-8 sequences unchanged
-};
-
-/// the default error handler of the CBOR, UBJSON, BJData, and BSON writers:
-/// error_handler_t::strict if JSON_STRICT_BINARY_UTF8 is enabled, otherwise
-/// error_handler_t::keep (the behavior before version 3.13.0)
-constexpr error_handler_t binary_writer_default_error_handler() noexcept
-{
-#if JSON_STRICT_BINARY_UTF8
-    return error_handler_t::strict;
-#else
-    return error_handler_t::keep;
-#endif
-}
-
-}  // namespace detail
-NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/detail/output/serializer.hpp

@@ -27,7 +27,6 @@
 #include <nlohmann/detail/input/string_scan.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/cpp_future.hpp>
-#include <nlohmann/detail/output/error_handler.hpp>
 #include <nlohmann/detail/output/output_adapters.hpp>
 #include <nlohmann/detail/recursion_depth_limit.hpp>
 #include <nlohmann/detail/string_concat.hpp>
@@ -42,6 +41,14 @@ namespace detail
 // serialization //
 ///////////////////
 
+/// how to treat decoding errors
+enum class error_handler_t
+{
+    strict,  ///< throw a type_error exception in case of invalid UTF-8
+    replace, ///< replace invalid UTF-8 sequences with U+FFFD
+    ignore   ///< ignore invalid UTF-8 sequences
+};
+
 template<typename BasicJsonType>
 class serializer
 {
@@ -832,16 +839,6 @@ class serializer
                             // EnsureAscii parameter is used, non-ASCII characters
                             if ((codepoint <= 0x1F) || (EnsureAscii && (codepoint >= 0x7F)))
                             {
-                                if (EnsureAscii && error_handler == error_handler_t::keep)
-                                {
-                                    // this character was buffered as raw bytes
-                                    // below in case it turned out to be part of
-                                    // an ill-formed sequence (which is kept as
-                                    // is); now that it decoded to a well-formed
-                                    // code point, undo that and \u-escape it
-                                    // like any other character instead
-                                    bytes = bytes_after_last_accept;
-                                }
                                 if (codepoint <= 0xFFFF)
                                 {
                                     write_u_escape(bytes, static_cast<std::uint16_t>(codepoint));
@@ -940,44 +937,6 @@ class serializer
                             break;
                         }
 
-                        case error_handler_t::keep:
-                        {
-                            // the bytes of this (now abandoned) ill-formed
-                            // sequence seen so far are already buffered below
-                            // and are kept unchanged in the output
-                            if (undumped_chars > 0)
-                            {
-                                // the byte that ended the sequence may be OK
-                                // for itself (e.g., a quote that must still be
-                                // escaped, or the lead byte of a well-formed
-                                // code point), so read it again
-                                --i;
-                            }
-                            else
-                            {
-                                // a byte that cannot start a sequence (e.g.,
-                                // 0xFF or a stray continuation byte) is kept
-                                // as well
-                                string_buffer[bytes++] = s[i];
-                            }
-
-                            // write buffer and reset index; there must be 13 bytes
-                            // left, as this is the maximal number of bytes to be
-                            // written ("\uxxxx\uxxxx\0") for one code point
-                            if (string_buffer.size() - bytes < 13)
-                            {
-                                put_buffer(string_buffer, bytes);
-                                bytes = 0;
-                            }
-
-                            bytes_after_last_accept = bytes;
-                            undumped_chars = 0;
-
-                            // continue processing the string
-                            state = UTF8_ACCEPT;
-                            break;
-                        }
-
                         default:            // LCOV_EXCL_LINE
                             JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
                     }
@@ -986,12 +945,9 @@ class serializer
 
                 default:  // decode found yet incomplete multibyte code point
                 {
-                    if (!EnsureAscii || error_handler == error_handler_t::keep)
+                    if (!EnsureAscii)
                     {
-                        // code point will not be escaped (or will be kept as
+                        // code point will not be escaped - copy byte to buffer
-                        // is if it turns out to be ill-formed) - copy byte to
-                        // buffer; dropped again above if it decodes to a
-                        // well-formed code point that needs \u-escaping
                         string_buffer[bytes++] = s[i];
                     }
                     ++undumped_chars;
@@ -1042,14 +998,6 @@ class serializer
                     break;
                 }
 
-                case error_handler_t::keep:
-                {
-                    // write the ill-formed trailing bytes as is; they were
-                    // buffered above regardless of EnsureAscii
-                    put_buffer(string_buffer, bytes);
-                    break;
-                }
-
                 default:            // LCOV_EXCL_LINE
                     JSON_ASSERT(false); // NOLINT(cert-dcl03-c,hicpp-static-assert,misc-static-assert) LCOV_EXCL_LINE
             }

include/nlohmann/detail/string_utils.hpp

@@ -16,7 +16,6 @@
 
 #include <nlohmann/detail/abi_macros.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
-#include <nlohmann/detail/output/error_handler.hpp>
 
 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
@@ -118,14 +117,13 @@ This is a single-byte step of a "shift-based" UTF-8 decoder originally
 written by Björn Hoehrmann. See
 http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ for details.
 
-The library checks UTF-8 well-formedness (RFC 3629, section 4) in three
+The library checks UTF-8 well-formedness (RFC 3629, section 4) in four
 places, which differ in speed, diagnostics, and how they read the input:
 
-- decode() below: the serializer, to escape and, in strict mode, reject
+- decode() and @ref is_valid_utf8 below: the serializer (to escape and, in
-  ill-formed UTF-8 when dumping a string. The CBOR, MessagePack, BSON,
+  strict mode, reject ill-formed UTF-8 when dumping a string) and the CBOR,
-  UBJSON and BJData readers do not use it: none of those specs requires a
+  MessagePack, BSON, UBJSON and BJData readers (to reject ill-formed UTF-8 in
-  decoder to reject ill-formed UTF-8 in text strings, so the readers keep
+  text strings at decode time).
-  the bytes as is and leave the check to dump() and the binary writers.
 - the per-lead-byte switch in lexer::scan_string(): JSON text, with a
   diagnostic for each kind of error.
 - validate_one_utf8() and valid_utf8_prefix() in string_scan.hpp: the lexer's
@@ -181,19 +179,19 @@ inline std::uint8_t decode(std::uint8_t& state, std::uint32_t& codep, const std:
 }
 
 /*!
-@brief check a string for well-formed UTF-8 (RFC 3629, section 4)
+@brief check whether a string consists solely of valid UTF-8
 
-Used by the binary readers (CBOR, MessagePack, UBJSON, BJData, BSON) when an
+Used by the CBOR/MessagePack/BSON/UBJSON binary readers to reject text
-@ref error_handler_t other than `keep` is requested for a text string value
+strings that are not valid UTF-8 at decode time (RFC 8949 §3.1 and the
-or object key: none of those formats requires a decoder to reject ill-formed
+MessagePack/BSON specifications all require text strings to be UTF-8), so
-UTF-8 on its own, so the check is opt-in there, unlike the JSON lexer and the
+that malformed input is caught immediately instead of only surfacing later
-serializer's @ref decode -based escaping, which always run it.
+as a type_error.316 when the resulting value is dumped.
 
 @param[in] s      the string to check
-@param[in] first  the index to start checking at
+@param[in] first  index of the first byte to check; the bytes before it are
-@return whether `s.substr(first)` is well-formed UTF-8
+                  assumed to have been validated already and to end on a
-
+                  code point boundary
-@sa @ref decode
+@return whether @a s (from index @a first on) is valid UTF-8
 */
 template<typename StringType>
 inline bool is_valid_utf8(const StringType& s, const std::size_t first = 0) noexcept
@@ -213,101 +211,5 @@ inline bool is_valid_utf8(const StringType& s, const std::size_t first = 0) noex
     return state == UTF8_ACCEPT;
 }
 
-/*!
-@brief sanitize a string with ill-formed UTF-8 for @ref error_handler_t::replace or @ref error_handler_t::ignore
-
-Replaces every maximal ill-formed subsequence with U+FFFD (`replace`) or
-drops it (`ignore`), using exactly the same boundaries @ref
-serializer::dump_escaped_impl uses while escaping a string: a byte that does
-not extend the sequence started by the previous byte(s) is reread as the
-start of a new one, instead of being swallowed along with them.
-
-@pre @a error_handler is @ref error_handler_t::replace or @ref error_handler_t::ignore
-@note Well-formed input is copied through unchanged, including bytes (e.g.
-      control characters or quotes) that @ref serializer::dump_escaped_impl
-      would itself escape; this function only concerns itself with
-      well-formedness, not with producing valid JSON text.
-
-@param[in] s              the string to sanitize
-@param[in] error_handler  @ref error_handler_t::replace or @ref error_handler_t::ignore
-
-@return @a s with every ill-formed subsequence replaced or removed
-
-@sa @ref decode
-*/
-template<typename StringType>
-inline StringType sanitize_utf8(const StringType& s, const error_handler_t error_handler)
-{
-    JSON_ASSERT(error_handler == error_handler_t::replace || error_handler == error_handler_t::ignore);
-
-    StringType result;
-    result.reserve(s.size());
-
-    std::uint32_t codepoint = 0;
-    std::uint8_t state = UTF8_ACCEPT;
-    // length of result after the last accepted code point
-    std::size_t result_len_after_last_accept = 0;
-    // whether bytes of an as yet unresolved sequence were already appended
-    bool pending = false;
-
-    for (std::size_t i = 0; i < s.size(); ++i)
-    {
-        switch (decode(state, codepoint, static_cast<std::uint8_t>(s[i])))
-        {
-            case UTF8_ACCEPT: // decode found a well-formed code point
-            {
-                result.push_back(s[i]);
-                result_len_after_last_accept = result.size();
-                pending = false;
-                break;
-            }
-
-            case UTF8_REJECT: // decode found an ill-formed byte
-            {
-                // in case we saw this byte for the first time, read it again,
-                // because it may be fine for itself, just not for the
-                // sequence that came before it
-                if (pending)
-                {
-                    --i;
-                }
-
-                // drop the bytes of the ill-formed sequence buffered below
-                result.resize(result_len_after_last_accept);
-
-                if (error_handler == error_handler_t::replace)
-                {
-                    result.append("\xEF\xBF\xBD");
-                    result_len_after_last_accept = result.size();
-                }
-
-                pending = false;
-                state = UTF8_ACCEPT;
-                break;
-            }
-
-            default: // decode found yet incomplete multibyte code point
-            {
-                result.push_back(s[i]);
-                pending = true;
-                break;
-            }
-        }
-    }
-
-    // the string ended with an incomplete sequence
-    if (state != UTF8_ACCEPT)
-    {
-        result.resize(result_len_after_last_accept);
-
-        if (error_handler == error_handler_t::replace)
-        {
-            result.append("\xEF\xBF\xBD");
-        }
-    }
-
-    return result;
-}
-
 }  // namespace detail
 NLOHMANN_JSON_NAMESPACE_END

include/nlohmann/json.hpp

@@ -201,10 +201,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     // used by the vector-returning to_* overloads
     template<typename CharType> using vector_binary_writer =
         ::nlohmann::detail::binary_writer<basic_json, CharType, ::nlohmann::detail::output_vector_sink<CharType>>;
-    template<typename CharType> static vector_binary_writer<CharType> vector_writer(
+    template<typename CharType> static vector_binary_writer<CharType> vector_writer(std::vector<CharType>& v)
-        std::vector<CharType>& v, const ::nlohmann::detail::error_handler_t error_handler = ::nlohmann::detail::binary_writer_default_error_handler())
     {
-        return vector_binary_writer<CharType>(::nlohmann::detail::output_vector_sink<CharType>(v), error_handler);
+        return vector_binary_writer<CharType>(::nlohmann::detail::output_vector_sink<CharType>(v));
     }
 
   JSON_PRIVATE_UNLESS_TESTED:
@@ -5446,87 +5445,78 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
   public:
     /// @brief create a CBOR serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_cbor/
-    static std::vector<std::uint8_t> to_cbor(const basic_json& j,
+    static std::vector<std::uint8_t> to_cbor(const basic_json& j)
-            const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
         std::vector<std::uint8_t> result;
         result.reserve(detail::binary_reserve_hint(j));
-        vector_writer(result, error_handler).write_cbor(j);
+        vector_writer(result).write_cbor(j);
         return result;
     }
 
     /// @brief create a CBOR serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_cbor/
-    static void to_cbor(const basic_json& j, detail::output_adapter<std::uint8_t> o,
+    static void to_cbor(const basic_json& j, detail::output_adapter<std::uint8_t> o)
-                        const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
-        binary_writer<std::uint8_t>(o, error_handler).write_cbor(j);
+        binary_writer<std::uint8_t>(o).write_cbor(j);
     }
 
     /// @brief create a CBOR serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_cbor/
-    static void to_cbor(const basic_json& j, detail::output_adapter<char> o,
+    static void to_cbor(const basic_json& j, detail::output_adapter<char> o)
-                        const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
-        binary_writer<char>(o, error_handler).write_cbor(j);
+        binary_writer<char>(o).write_cbor(j);
     }
 
     /// @brief create a MessagePack serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_msgpack/
-    static std::vector<std::uint8_t> to_msgpack(const basic_json& j,
+    static std::vector<std::uint8_t> to_msgpack(const basic_json& j)
-            const error_handler_t error_handler = error_handler_t::keep)
     {
         std::vector<std::uint8_t> result;
         result.reserve(detail::binary_reserve_hint(j));
-        vector_writer(result, error_handler).write_msgpack(j);
+        vector_writer(result).write_msgpack(j);
         return result;
     }
 
     /// @brief create a MessagePack serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_msgpack/
-    static void to_msgpack(const basic_json& j, detail::output_adapter<std::uint8_t> o,
+    static void to_msgpack(const basic_json& j, detail::output_adapter<std::uint8_t> o)
-                           const error_handler_t error_handler = error_handler_t::keep)
     {
-        binary_writer<std::uint8_t>(o, error_handler).write_msgpack(j);
+        binary_writer<std::uint8_t>(o).write_msgpack(j);
     }
 
     /// @brief create a MessagePack serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_msgpack/
-    static void to_msgpack(const basic_json& j, detail::output_adapter<char> o,
+    static void to_msgpack(const basic_json& j, detail::output_adapter<char> o)
-                           const error_handler_t error_handler = error_handler_t::keep)
     {
-        binary_writer<char>(o, error_handler).write_msgpack(j);
+        binary_writer<char>(o).write_msgpack(j);
     }
 
     /// @brief create a UBJSON serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_ubjson/
     static std::vector<std::uint8_t> to_ubjson(const basic_json& j,
             const bool use_size = false,
-            const bool use_type = false,
+            const bool use_type = false)
-            const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
         std::vector<std::uint8_t> result;
         result.reserve(detail::binary_reserve_hint(j));
-        vector_writer(result, error_handler).write_ubjson(j, use_size, use_type);
+        vector_writer(result).write_ubjson(j, use_size, use_type);
         return result;
     }
 
     /// @brief create a UBJSON serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_ubjson/
     static void to_ubjson(const basic_json& j, detail::output_adapter<std::uint8_t> o,
-                          const bool use_size = false, const bool use_type = false,
+                          const bool use_size = false, const bool use_type = false)
-                          const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
-        binary_writer<std::uint8_t>(o, error_handler).write_ubjson(j, use_size, use_type);
+        binary_writer<std::uint8_t>(o).write_ubjson(j, use_size, use_type);
     }
 
     /// @brief create a UBJSON serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_ubjson/
     static void to_ubjson(const basic_json& j, detail::output_adapter<char> o,
-                          const bool use_size = false, const bool use_type = false,
+                          const bool use_size = false, const bool use_type = false)
-                          const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
-        binary_writer<char>(o, error_handler).write_ubjson(j, use_size, use_type);
+        binary_writer<char>(o).write_ubjson(j, use_size, use_type);
     }
 
     /// @brief create a BJData serialization of a given JSON value
@@ -5534,12 +5524,11 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     static std::vector<std::uint8_t> to_bjdata(const basic_json& j,
             const bool use_size = false,
             const bool use_type = false,
-            const bjdata_version_t version = bjdata_version_t::draft2,
+            const bjdata_version_t version = bjdata_version_t::draft2)
-            const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
         std::vector<std::uint8_t> result;
         result.reserve(detail::binary_reserve_hint(j));
-        vector_writer(result, error_handler).write_ubjson(j, use_size, use_type, true, true, version);
+        vector_writer(result).write_ubjson(j, use_size, use_type, true, true, version);
         return result;
     }
 
@@ -5547,47 +5536,42 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     /// @sa https://json.nlohmann.me/api/basic_json/to_bjdata/
     static void to_bjdata(const basic_json& j, detail::output_adapter<std::uint8_t> o,
                           const bool use_size = false, const bool use_type = false,
-                          const bjdata_version_t version = bjdata_version_t::draft2,
+                          const bjdata_version_t version = bjdata_version_t::draft2)
-                          const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
-        binary_writer<std::uint8_t>(o, error_handler).write_ubjson(j, use_size, use_type, true, true, version);
+        binary_writer<std::uint8_t>(o).write_ubjson(j, use_size, use_type, true, true, version);
     }
 
     /// @brief create a BJData serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_bjdata/
     static void to_bjdata(const basic_json& j, detail::output_adapter<char> o,
                           const bool use_size = false, const bool use_type = false,
-                          const bjdata_version_t version = bjdata_version_t::draft2,
+                          const bjdata_version_t version = bjdata_version_t::draft2)
-                          const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
-        binary_writer<char>(o, error_handler).write_ubjson(j, use_size, use_type, true, true, version);
+        binary_writer<char>(o).write_ubjson(j, use_size, use_type, true, true, version);
     }
 
     /// @brief create a BSON serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_bson/
-    static std::vector<std::uint8_t> to_bson(const basic_json& j,
+    static std::vector<std::uint8_t> to_bson(const basic_json& j)
-            const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
         std::vector<std::uint8_t> result;
         result.reserve(detail::binary_reserve_hint(j));
-        vector_writer(result, error_handler).write_bson(j);
+        vector_writer(result).write_bson(j);
         return result;
     }
 
     /// @brief create a BSON serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_bson/
-    static void to_bson(const basic_json& j, detail::output_adapter<std::uint8_t> o,
+    static void to_bson(const basic_json& j, detail::output_adapter<std::uint8_t> o)
-                        const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
-        binary_writer<std::uint8_t>(o, error_handler).write_bson(j);
+        binary_writer<std::uint8_t>(o).write_bson(j);
     }
 
     /// @brief create a BSON serialization of a given JSON value
     /// @sa https://json.nlohmann.me/api/basic_json/to_bson/
-    static void to_bson(const basic_json& j, detail::output_adapter<char> o,
+    static void to_bson(const basic_json& j, detail::output_adapter<char> o)
-                        const error_handler_t error_handler = detail::binary_writer_default_error_handler())
     {
-        binary_writer<char>(o, error_handler).write_bson(j);
+        binary_writer<char>(o).write_bson(j);
     }
 
     /// @brief create a BON8 serialization of a given JSON value
@@ -5621,13 +5605,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     static basic_json from_cbor(InputType&& i,
                                 const bool strict = true,
                                 const bool allow_exceptions = true,
-                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error,
+                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
-                                const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::forward<InputType>(i));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor, error_handler).sax_parse(&sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(&sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5642,13 +5625,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     static basic_json from_cbor(IteratorType first, SentinelType last,
                                 const bool strict = true,
                                 const bool allow_exceptions = true,
-                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error,
+                                const cbor_tag_handler_t tag_handler = cbor_tag_handler_t::error)
-                                const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor, error_handler).sax_parse(&sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(&sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5690,13 +5672,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_msgpack(InputType&& i,
                                    const bool strict = true,
-                                   const bool allow_exceptions = true,
+                                   const bool allow_exceptions = true)
-                                   const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::forward<InputType>(i));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack, error_handler).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5710,13 +5691,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_msgpack(IteratorType first, SentinelType last,
                                    const bool strict = true,
-                                   const bool allow_exceptions = true,
+                                   const bool allow_exceptions = true)
-                                   const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack, error_handler).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5756,13 +5736,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_ubjson(InputType&& i,
                                   const bool strict = true,
-                                  const bool allow_exceptions = true,
+                                  const bool allow_exceptions = true)
-                                  const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::forward<InputType>(i));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson, error_handler).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5776,13 +5755,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_ubjson(IteratorType first, SentinelType last,
                                   const bool strict = true,
-                                  const bool allow_exceptions = true,
+                                  const bool allow_exceptions = true)
-                                  const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson, error_handler).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5822,13 +5800,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_bjdata(InputType&& i,
                                   const bool strict = true,
-                                  const bool allow_exceptions = true,
+                                  const bool allow_exceptions = true)
-                                  const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::forward<InputType>(i));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata, error_handler).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5842,13 +5819,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_bjdata(IteratorType first, SentinelType last,
                                   const bool strict = true,
-                                  const bool allow_exceptions = true,
+                                  const bool allow_exceptions = true)
-                                  const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata, error_handler).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5898,13 +5874,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_bson(InputType&& i,
                                 const bool strict = true,
-                                const bool allow_exceptions = true,
+                                const bool allow_exceptions = true)
-                                const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::forward<InputType>(i));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson, error_handler).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }
@@ -5918,13 +5893,12 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     JSON_HEDLEY_WARN_UNUSED_RESULT
     static basic_json from_bson(IteratorType first, SentinelType last,
                                 const bool strict = true,
-                                const bool allow_exceptions = true,
+                                const bool allow_exceptions = true)
-                                const error_handler_t error_handler = error_handler_t::keep)
     {
         basic_json result;
         auto ia = detail::input_adapter(std::move(first), std::move(last));
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson, error_handler).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
+        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(&sdp, strict)) // cppcheck-suppress[accessMoved]
         {
             result = value_t::discarded;
         }

single_include/nlohmann/json_fwd.hpp

@@ -63,10 +63,6 @@
     #define JSON_STRICT_NUL_HANDLING 0
 #endif
 
-#ifndef JSON_STRICT_BINARY_UTF8
-    #define JSON_STRICT_BINARY_UTF8 0
-#endif
-
 #if JSON_DIAGNOSTICS
     #define NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS _diag
 #else
@@ -103,20 +99,14 @@
     #define NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING
 #endif
 
-#if JSON_STRICT_BINARY_UTF8
-    #define NLOHMANN_JSON_ABI_TAG_STRICT_BINARY_UTF8 _sbu8
-#else
-    #define NLOHMANN_JSON_ABI_TAG_STRICT_BINARY_UTF8
-#endif
-
 #ifndef NLOHMANN_JSON_NAMESPACE_NO_VERSION
     #define NLOHMANN_JSON_NAMESPACE_NO_VERSION 0
 #endif
 
 // Construct the namespace ABI tags component
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g) json_abi ## a ## b ## c ## d ## e ## f ## g
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f) json_abi ## a ## b ## c ## d ## e ## f
-#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f, g) \
+#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f) \
-    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g)
+    NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f)
 
 #define NLOHMANN_JSON_ABI_TAGS                                       \
     NLOHMANN_JSON_ABI_TAGS_CONCAT(                                   \
@@ -125,8 +115,7 @@
             NLOHMANN_JSON_ABI_TAG_DIAGNOSTIC_POSITIONS,              \
             NLOHMANN_JSON_ABI_TAG_BRACE_INIT_COPY_SEMANTICS,         \
             NLOHMANN_JSON_ABI_TAG_PRECISE_STREAM_POSITION,           \
-            NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING,               \
+            NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING)
-            NLOHMANN_JSON_ABI_TAG_STRICT_BINARY_UTF8)
 
 // Construct the namespace version component
 #define NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT_EX(major, minor, patch) \

tests/abi/config/default.cpp

@@ -44,10 +44,6 @@ TEST_CASE("default namespace")
         expected += "_snul";
 #endif
 
-#if JSON_STRICT_BINARY_UTF8
-        expected += "_sbu8";
-#endif
-
         expected += "_v" STRINGIZE(NLOHMANN_JSON_VERSION_MAJOR);
         expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_MINOR);
         expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_PATCH) "::basic_json";

tests/abi/config/noversion.cpp

@@ -45,10 +45,6 @@ TEST_CASE("default namespace without version component")
         expected += "_snul";
 #endif
 
-#if JSON_STRICT_BINARY_UTF8
-        expected += "_sbu8";
-#endif
-
         expected += "::basic_json";
 
         // fallback for Clang

tests/src/unit-binary_utf8_error_handler.cpp

@@ -1,362 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#include "doctest_compatibility.h"
-
-#include <nlohmann/json.hpp>
-using nlohmann::json;
-
-#include <string>
-#include <vector>
-
-namespace
-{
-
-struct ill_formed_case
-{
-    const char* name;
-    std::string bytes;
-};
-
-// RFC 3629 ill-formed sequences used throughout this file, plus one
-// well-formed sequence for contrast
-const std::vector<ill_formed_case> ill_formed_cases =
-{
-    {"overlong", "\xC0\xAE"},
-    {"lone_0xFF", "\xFF"},
-    {"truncated", "\xE2\x82"},
-    {"surrogate", "\xED\xA0\x80"},
-};
-
-const std::string valid_sequence = "\xC3\xA9"; // U+00E9, "é"
-
-using eh = json::error_handler_t;
-const std::vector<eh> all_handlers = {eh::strict, eh::replace, eh::ignore, eh::keep};
-
-// what dump()+parse() produces for a sanitizing error_handler; this is the
-// ground truth every binary writer/reader is checked against
-std::string dump_and_parse(const std::string& raw, eh error_handler)
-{
-    return json::parse(json(raw).dump(-1, ' ', false, error_handler)).get<std::string>();
-}
-
-} // namespace
-
-TEST_CASE("UTF-8 error_handler for the binary readers and writers")
-{
-    SECTION("writers: string value")
-    {
-        for (const auto& c : ill_formed_cases)
-        {
-            CAPTURE(c.name);
-            const json jval = c.bytes;
-
-            CHECK_THROWS_AS(json::to_cbor(jval, eh::strict), json::type_error&);
-            CHECK_THROWS_AS(json::to_msgpack(jval, eh::strict), json::type_error&);
-            CHECK_THROWS_AS(json::to_ubjson(jval, false, false, eh::strict), json::type_error&);
-            CHECK_THROWS_AS(json::to_bjdata(jval, false, false, json::bjdata_version_t::draft2, eh::strict), json::type_error&);
-            {
-                json jobj;
-                jobj["k"] = jval;
-                CHECK_THROWS_AS(json::to_bson(jobj, eh::strict), json::type_error&);
-            }
-
-            for (const auto h :
-                    {
-                        eh::replace, eh::ignore
-                    })
-            {
-                CAPTURE(static_cast<int>(h));
-                const std::string expected = dump_and_parse(c.bytes, h);
-
-                CHECK(json::from_cbor(json::to_cbor(jval, h)).get<std::string>() == expected);
-                CHECK(json::from_msgpack(json::to_msgpack(jval, h)).get<std::string>() == expected);
-                CHECK(json::from_ubjson(json::to_ubjson(jval, false, false, h)).get<std::string>() == expected);
-                CHECK(json::from_bjdata(json::to_bjdata(jval, false, false, json::bjdata_version_t::draft2, h)).get<std::string>() == expected);
-                {
-                    json jobj;
-                    jobj["k"] = jval;
-                    const auto bytes = json::to_bson(jobj, h);
-                    CHECK(json::from_bson(bytes)["k"].get<std::string>() == expected);
-                }
-            }
-
-            // keep: the writer passes the ill-formed bytes through unchanged,
-            // exactly as every binary writer did before this parameter existed
-            CHECK(json::from_cbor(json::to_cbor(jval, eh::keep)).get<std::string>() == c.bytes);
-            CHECK(json::from_msgpack(json::to_msgpack(jval, eh::keep)).get<std::string>() == c.bytes);
-            CHECK(json::from_ubjson(json::to_ubjson(jval, false, false, eh::keep)).get<std::string>() == c.bytes);
-            CHECK(json::from_bjdata(json::to_bjdata(jval, false, false, json::bjdata_version_t::draft2, eh::keep)).get<std::string>() == c.bytes);
-            {
-                json jobj;
-                jobj["k"] = jval;
-                const auto bytes = json::to_bson(jobj, eh::keep);
-                CHECK(json::from_bson(bytes)["k"].get<std::string>() == c.bytes);
-            }
-        }
-    }
-
-    SECTION("writers: object key")
-    {
-        for (const auto& c : ill_formed_cases)
-        {
-            CAPTURE(c.name);
-            json jobj;
-            jobj[c.bytes] = 1;
-
-            CHECK_THROWS_AS(json::to_cbor(jobj, eh::strict), json::type_error&);
-            CHECK_THROWS_AS(json::to_msgpack(jobj, eh::strict), json::type_error&);
-            CHECK_THROWS_AS(json::to_ubjson(jobj, false, false, eh::strict), json::type_error&);
-            CHECK_THROWS_AS(json::to_bjdata(jobj, false, false, json::bjdata_version_t::draft2, eh::strict), json::type_error&);
-            CHECK_THROWS_AS(json::to_bson(jobj, eh::strict), json::type_error&);
-
-            for (const auto h :
-                    {
-                        eh::replace, eh::ignore
-                    })
-            {
-                CAPTURE(static_cast<int>(h));
-                const std::string expected = dump_and_parse(c.bytes, h);
-
-                CHECK(json::from_cbor(json::to_cbor(jobj, h)).begin().key() == expected);
-                CHECK(json::from_msgpack(json::to_msgpack(jobj, h)).begin().key() == expected);
-                CHECK(json::from_ubjson(json::to_ubjson(jobj, false, false, h)).begin().key() == expected);
-                CHECK(json::from_bjdata(json::to_bjdata(jobj, false, false, json::bjdata_version_t::draft2, h)).begin().key() == expected);
-                CHECK(json::from_bson(json::to_bson(jobj, h)).begin().key() == expected);
-            }
-
-            // keep: object keys round-trip unchanged too
-            CHECK(json::from_cbor(json::to_cbor(jobj, eh::keep)).begin().key() == c.bytes);
-            CHECK(json::from_msgpack(json::to_msgpack(jobj, eh::keep)).begin().key() == c.bytes);
-            CHECK(json::from_ubjson(json::to_ubjson(jobj, false, false, eh::keep)).begin().key() == c.bytes);
-            CHECK(json::from_bjdata(json::to_bjdata(jobj, false, false, json::bjdata_version_t::draft2, eh::keep)).begin().key() == c.bytes);
-            CHECK(json::from_bson(json::to_bson(jobj, eh::keep)).begin().key() == c.bytes);
-        }
-    }
-
-    SECTION("readers: string value")
-    {
-        for (const auto& c : ill_formed_cases)
-        {
-            CAPTURE(c.name);
-
-            // bytes produced the lenient (keep) way, as any binary reader
-            // accepted them before this parameter existed
-            const auto cbor_bytes = json::to_cbor(json(c.bytes), eh::keep);
-            const auto msgpack_bytes = json::to_msgpack(json(c.bytes)); // to_msgpack has no error_handler; always pass-through
-            const auto ubjson_bytes = json::to_ubjson(json(c.bytes), false, false, eh::keep);
-            const auto bjdata_bytes = json::to_bjdata(json(c.bytes), false, false, json::bjdata_version_t::draft2, eh::keep);
-            const auto bson_bytes = [&c]
-            {
-                json jobj;
-                jobj["k"] = c.bytes;
-                return json::to_bson(jobj, eh::keep);
-            }();
-
-            // keep (the default): bytes are kept unchanged
-            CHECK(json::from_cbor(cbor_bytes).get<std::string>() == c.bytes);
-            CHECK(json::from_msgpack(msgpack_bytes).get<std::string>() == c.bytes);
-            CHECK(json::from_ubjson(ubjson_bytes).get<std::string>() == c.bytes);
-            CHECK(json::from_bjdata(bjdata_bytes).get<std::string>() == c.bytes);
-            CHECK(json::from_bson(bson_bytes)["k"].get<std::string>() == c.bytes);
-
-            // strict: parse_error.113, discarded (not thrown) when allow_exceptions is false
-            CHECK_THROWS_AS(json::from_cbor(cbor_bytes, true, true, json::cbor_tag_handler_t::error, eh::strict), json::parse_error&);
-            CHECK(json::from_cbor(cbor_bytes, true, false, json::cbor_tag_handler_t::error, eh::strict).is_discarded());
-            CHECK_THROWS_AS(json::from_msgpack(msgpack_bytes, true, true, eh::strict), json::parse_error&);
-            CHECK(json::from_msgpack(msgpack_bytes, true, false, eh::strict).is_discarded());
-            CHECK_THROWS_AS(json::from_ubjson(ubjson_bytes, true, true, eh::strict), json::parse_error&);
-            CHECK(json::from_ubjson(ubjson_bytes, true, false, eh::strict).is_discarded());
-            CHECK_THROWS_AS(json::from_bjdata(bjdata_bytes, true, true, eh::strict), json::parse_error&);
-            CHECK(json::from_bjdata(bjdata_bytes, true, false, eh::strict).is_discarded());
-            CHECK_THROWS_AS(json::from_bson(bson_bytes, true, true, eh::strict), json::parse_error&);
-            CHECK(json::from_bson(bson_bytes, true, false, eh::strict).is_discarded());
-
-            // replace / ignore: match what dump() would have sanitized the same bytes to
-            for (const auto h :
-                    {
-                        eh::replace, eh::ignore
-                    })
-            {
-                CAPTURE(static_cast<int>(h));
-                const std::string expected = dump_and_parse(c.bytes, h);
-
-                CHECK(json::from_cbor(cbor_bytes, true, true, json::cbor_tag_handler_t::error, h).get<std::string>() == expected);
-                CHECK(json::from_msgpack(msgpack_bytes, true, true, h).get<std::string>() == expected);
-                CHECK(json::from_ubjson(ubjson_bytes, true, true, h).get<std::string>() == expected);
-                CHECK(json::from_bjdata(bjdata_bytes, true, true, h).get<std::string>() == expected);
-                CHECK(json::from_bson(bson_bytes, true, true, h)["k"].get<std::string>() == expected);
-            }
-        }
-    }
-
-    SECTION("readers: object key")
-    {
-        for (const auto& c : ill_formed_cases)
-        {
-            CAPTURE(c.name);
-
-            json jobj;
-            jobj[c.bytes] = 1;
-            const auto cbor_bytes = json::to_cbor(jobj, eh::keep);
-            const auto msgpack_bytes = json::to_msgpack(jobj);
-            const auto ubjson_bytes = json::to_ubjson(jobj, false, false, eh::keep);
-            const auto bjdata_bytes = json::to_bjdata(jobj, false, false, json::bjdata_version_t::draft2, eh::keep);
-            const auto bson_bytes = json::to_bson(jobj, eh::keep);
-
-            CHECK(json::from_cbor(cbor_bytes).begin().key() == c.bytes);
-            CHECK(json::from_msgpack(msgpack_bytes).begin().key() == c.bytes);
-            CHECK(json::from_ubjson(ubjson_bytes).begin().key() == c.bytes);
-            CHECK(json::from_bjdata(bjdata_bytes).begin().key() == c.bytes);
-            CHECK(json::from_bson(bson_bytes).begin().key() == c.bytes);
-
-            CHECK_THROWS_AS(json::from_cbor(cbor_bytes, true, true, json::cbor_tag_handler_t::error, eh::strict), json::parse_error&);
-            CHECK_THROWS_AS(json::from_msgpack(msgpack_bytes, true, true, eh::strict), json::parse_error&);
-            CHECK_THROWS_AS(json::from_ubjson(ubjson_bytes, true, true, eh::strict), json::parse_error&);
-            CHECK_THROWS_AS(json::from_bjdata(bjdata_bytes, true, true, eh::strict), json::parse_error&);
-            CHECK_THROWS_AS(json::from_bson(bson_bytes, true, true, eh::strict), json::parse_error&);
-
-            for (const auto h :
-                    {
-                        eh::replace, eh::ignore
-                    })
-            {
-                CAPTURE(static_cast<int>(h));
-                const std::string expected = dump_and_parse(c.bytes, h);
-
-                CHECK(json::from_cbor(cbor_bytes, true, true, json::cbor_tag_handler_t::error, h).begin().key() == expected);
-                CHECK(json::from_msgpack(msgpack_bytes, true, true, h).begin().key() == expected);
-                CHECK(json::from_ubjson(ubjson_bytes, true, true, h).begin().key() == expected);
-                CHECK(json::from_bjdata(bjdata_bytes, true, true, h).begin().key() == expected);
-                CHECK(json::from_bson(bson_bytes, true, true, h).begin().key() == expected);
-            }
-        }
-    }
-
-    SECTION("well-formed UTF-8 is unaffected by error_handler")
-    {
-        const json jval = valid_sequence;
-        json jobj;
-        jobj[valid_sequence] = valid_sequence;
-
-        for (const auto h : all_handlers)
-        {
-            CAPTURE(static_cast<int>(h));
-
-            CHECK(json::from_cbor(json::to_cbor(jval, h)).get<std::string>() == valid_sequence);
-            CHECK(json::from_msgpack(json::to_msgpack(jval, h)).get<std::string>() == valid_sequence);
-            CHECK(json::from_ubjson(json::to_ubjson(jval, false, false, h)).get<std::string>() == valid_sequence);
-            CHECK(json::from_bjdata(json::to_bjdata(jval, false, false, json::bjdata_version_t::draft2, h)).get<std::string>() == valid_sequence);
-            CHECK(json::from_bson(json::to_bson(jobj, h)).begin().key() == valid_sequence);
-
-            CHECK(json::from_cbor(json::to_cbor(jval, eh::keep), true, true, json::cbor_tag_handler_t::error, h).get<std::string>() == valid_sequence);
-            CHECK(json::from_msgpack(json::to_msgpack(jval), true, true, h).get<std::string>() == valid_sequence);
-        }
-    }
-
-    SECTION("dump() with error_handler_t::keep writes raw bytes as is")
-    {
-        for (const auto& c : ill_formed_cases)
-        {
-            CAPTURE(c.name);
-
-            const json jval = c.bytes;
-            const std::string dumped = jval.dump(-1, ' ', false, eh::keep);
-            CHECK(dumped.find(c.bytes) != std::string::npos);
-
-            // even with ensure_ascii, the ill-formed bytes are written as is
-            const std::string dumped_ascii = jval.dump(-1, ' ', true, eh::keep);
-            CHECK(dumped_ascii.find(c.bytes) != std::string::npos);
-        }
-
-        // well-formed characters around an ill-formed sequence are still
-        // escaped as usual under ensure_ascii
-        const json mixed = valid_sequence + ill_formed_cases[1].bytes; // "é" + lone 0xFF
-        const std::string dumped_mixed = mixed.dump(-1, ' ', true, eh::keep);
-        CHECK(dumped_mixed.find("\\u00e9") != std::string::npos);
-        CHECK(dumped_mixed.find(ill_formed_cases[1].bytes) != std::string::npos);
-
-        // the byte that ends an ill-formed sequence is read again, so a quote,
-        // a backslash, or a control character after it is still escaped, and
-        // a well-formed code point after it is escaped under ensure_ascii
-        for (const bool ensure_ascii :
-                {
-                    false, true
-                })
-        {
-            CAPTURE(ensure_ascii);
-            CHECK(json("\xC3\"").dump(-1, ' ', ensure_ascii, eh::keep) == "\"\xC3\\\"\"");
-            CHECK(json("\xC3\\").dump(-1, ' ', ensure_ascii, eh::keep) == "\"\xC3\\\\\"");
-            CHECK(json("\xC3\n").dump(-1, ' ', ensure_ascii, eh::keep) == "\"\xC3\\n\"");
-            CHECK(json("\xE2\x82\"").dump(-1, ' ', ensure_ascii, eh::keep) == "\"\xE2\x82\\\"\"");
-            CHECK(json("\xFF\"").dump(-1, ' ', ensure_ascii, eh::keep) == "\"\xFF\\\"\"");
-            CHECK(json("a\xE2\x82").dump(-1, ' ', ensure_ascii, eh::keep) == "\"a\xE2\x82\"");
-        }
-        CHECK(json("\xC3\xC3\xA9").dump(-1, ' ', false, eh::keep) == "\"\xC3\xC3\xA9\"");
-        CHECK(json("\xC3\xC3\xA9").dump(-1, ' ', true, eh::keep) == "\"\xC3\\u00e9\"");
-    }
-
-    SECTION("to_msgpack defaults to keep; to_bon8 is not affected by error_handler")
-    {
-        const json jval = ill_formed_cases[1].bytes; // lone 0xFF
-
-        // to_msgpack's error_handler defaults to keep, as MessagePack's spec
-        // allows any bytes in a str, so the bytes are passed through
-        CHECK(json::to_msgpack(jval) == json::to_msgpack(jval, eh::keep));
-        CHECK(json::from_msgpack(json::to_msgpack(jval)).get<std::string>() == ill_formed_cases[1].bytes);
-
-        // the diagnostics context of an ill-formed key is the object
-        json jobj;
-        jobj["\xFF"] = 1;
-        CHECK_THROWS_WITH_AS(json::to_msgpack(jobj, eh::strict), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-
-        // to_bon8 has no error_handler parameter; UTF-8 is structural for
-        // BON8, so it always rejects ill-formed input
-        CHECK_THROWS_AS(json::to_bon8(jval), json::type_error&);
-    }
-
-    SECTION("allow_exceptions=false with error_handler_t::strict discards the value")
-    {
-        const auto bytes = json::to_cbor(json(ill_formed_cases[0].bytes), eh::keep);
-        const json result = json::from_cbor(bytes, true, false, json::cbor_tag_handler_t::error, eh::strict);
-        CHECK(result.is_discarded());
-    }
-
-    SECTION("default parameters are unchanged")
-    {
-        const json jval = ill_formed_cases[0].bytes;
-
-        // to_*: the default error_handler is keep, so ill-formed bytes are
-        // written unchanged, exactly as in release 3.12.0 (it is strict only
-        // if JSON_STRICT_BINARY_UTF8 is enabled, see
-        // unit-binary_utf8_strict.cpp)
-        CHECK(json::to_cbor(jval) == json::to_cbor(jval, eh::keep));
-        CHECK(json::to_ubjson(jval) == json::to_ubjson(jval, false, false, eh::keep));
-        CHECK(json::to_bjdata(jval) == json::to_bjdata(jval, false, false, json::bjdata_version_t::draft2, eh::keep));
-        {
-            json jobj;
-            jobj["k"] = jval;
-            CHECK(json::to_bson(jobj) == json::to_bson(jobj, eh::keep));
-        }
-
-        // from_*: the default error_handler is keep, so ill-formed bytes are
-        // still accepted unchanged, exactly as in release 3.12.0
-        const auto cbor_bytes = json::to_cbor(jval, eh::keep);
-        CHECK(json::from_cbor(cbor_bytes).get<std::string>() == ill_formed_cases[0].bytes);
-        const auto ubjson_bytes = json::to_ubjson(jval, false, false, eh::keep);
-        CHECK(json::from_ubjson(ubjson_bytes).get<std::string>() == ill_formed_cases[0].bytes);
-        const auto bjdata_bytes = json::to_bjdata(jval, false, false, json::bjdata_version_t::draft2, eh::keep);
-        CHECK(json::from_bjdata(bjdata_bytes).get<std::string>() == ill_formed_cases[0].bytes);
-        const auto msgpack_bytes = json::to_msgpack(jval);
-        CHECK(json::from_msgpack(msgpack_bytes).get<std::string>() == ill_formed_cases[0].bytes);
-        json bson_obj;
-        bson_obj["k"] = jval;
-        const auto bson_bytes = json::to_bson(bson_obj, eh::keep);
-        CHECK(json::from_bson(bson_bytes)["k"].get<std::string>() == ill_formed_cases[0].bytes);
-    }
-}

tests/src/unit-binary_utf8_strict.cpp

@@ -1,122 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#include "doctest_compatibility.h"
-
-// The binary writers check strings and object keys for valid UTF-8 only if
-// JSON_STRICT_BINARY_UTF8 is enabled (planned to be the default in 4.0.0).
-// Without it, they write the bytes unchanged, as before version 3.13.0; the
-// tests for that are next to the other tests of each format.
-#ifdef JSON_STRICT_BINARY_UTF8
-    #undef JSON_STRICT_BINARY_UTF8
-#endif
-
-#define JSON_STRICT_BINARY_UTF8 1
-
-#include <nlohmann/json.hpp>
-using nlohmann::json;
-
-#include <cstdint>
-#include <vector>
-
-TEST_CASE("JSON_STRICT_BINARY_UTF8 (see #5529, #5651)")
-{
-    SECTION("CBOR")
-    {
-        // a string value with ill-formed UTF-8 is rejected
-        CHECK_THROWS_WITH_AS(json::to_cbor(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-        // a truncated multi-byte sequence
-        CHECK_THROWS_WITH_AS(json::to_cbor(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
-        // an encoded surrogate half (U+D800)
-        CHECK_THROWS_WITH_AS(json::to_cbor(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
-        // an overlong encoding of '.'
-        CHECK_THROWS_WITH_AS(json::to_cbor(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
-
-        // an object key with ill-formed UTF-8 is rejected the same way
-        CHECK_THROWS_WITH_AS(json::to_cbor(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-
-        // binary values are not text and are unaffected
-        CHECK_NOTHROW(json::to_cbor(json::binary(std::vector<std::uint8_t>({0xFF}))));
-
-        // a value read back from CBOR with ill-formed bytes cannot be written
-        // back either (the reader is lenient regardless of the macro)
-        const json j = json::from_cbor(std::vector<std::uint8_t>({0x62, 0xc0, 0xae}));
-        CHECK_THROWS_WITH_AS(json::to_cbor(j), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
-    }
-
-    SECTION("UBJSON")
-    {
-        CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-        // a truncated multi-byte sequence
-        CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
-        // an encoded surrogate half (U+D800)
-        CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
-        // an overlong encoding of '.'
-        CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
-
-        // an object key with ill-formed UTF-8 is rejected the same way
-        CHECK_THROWS_WITH_AS(json::to_ubjson(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-    }
-
-    SECTION("BJData")
-    {
-        CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-        // a truncated multi-byte sequence
-        CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
-        // an encoded surrogate half (U+D800)
-        CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
-        // an overlong encoding of '.'
-        CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
-
-        // an object key with ill-formed UTF-8 is rejected the same way
-        CHECK_THROWS_WITH_AS(json::to_bjdata(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-    }
-
-    SECTION("BSON")
-    {
-        // to_bson() rejects the same kind of ill-formed string value, before
-        // any bytes reach the output adapter (the BSON document length
-        // prefix must be known up front, so nothing is written incrementally)
-        std::vector<std::uint8_t> out{0x42}; // a sentinel byte the writer must not touch
-        CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xFF"}}, nlohmann::detail::output_adapter<std::uint8_t>(out)), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-        CHECK(out == std::vector<std::uint8_t> {0x42});
-
-        CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xFF"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-        // a truncated multi-byte sequence
-        CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xC3"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
-        // an encoded surrogate half (U+D800)
-        CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xED\xA0\x80"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
-        // an overlong encoding of '.'
-        CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xC0\xAF"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
-
-        // an object key with ill-formed UTF-8 is rejected as well; unlike
-        // the reader (which never validates element names), the writer
-        // checks both string values and object keys
-        CHECK_THROWS_WITH_AS(json::to_bson(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
-    }
-
-    SECTION("an explicit error_handler overrides the default")
-    {
-        // the macro only changes the default of the error_handler parameter
-        CHECK(json::to_cbor(json("\xFF"), json::error_handler_t::keep) == std::vector<std::uint8_t>({0x61, 0xff}));
-        CHECK(json::to_ubjson(json("\xFF"), false, false, json::error_handler_t::keep) == std::vector<std::uint8_t>({'S', 'i', 1, 0xff}));
-        CHECK(json::to_bjdata(json("\xFF"), false, false, json::bjdata_version_t::draft2, json::error_handler_t::keep) == std::vector<std::uint8_t>({'S', 'i', 1, 0xff}));
-        CHECK(json::from_bson(json::to_bson(json{{"s", "\xFF"}}, json::error_handler_t::keep)) == json{{"s", "\xFF"}});
-        CHECK(json::to_cbor(json("\xFF"), json::error_handler_t::replace) == std::vector<std::uint8_t>({0x63, 0xef, 0xbf, 0xbd}));
-    }
-
-    SECTION("MessagePack and BON8 are unaffected")
-    {
-        // MessagePack allows any bytes in a str, so to_msgpack() still
-        // defaults to keep (strict only if passed explicitly); BON8 always
-        // checks, because the lead bytes mark where strings end
-        CHECK(json::to_msgpack(json("\xFF")) == std::vector<std::uint8_t>({0xa1, 0xff}));
-        CHECK_THROWS_AS(json::to_msgpack(json("\xFF"), json::error_handler_t::strict), json::type_error&);
-        CHECK_THROWS_AS(json::to_bon8(json("\xFF")), json::type_error&);
-    }
-}

tests/src/unit-bjdata.cpp

@@ -3907,43 +3907,6 @@ TEST_CASE("Universal Binary JSON Specification Examples 1")
             CHECK(json::to_bjdata(j) == v);
             CHECK(json::from_bjdata(v) == j);
         }
-
-        SECTION("ill-formed UTF-8 (see #5529, #5651)")
-        {
-            // none of the binary format specs requires a decoder to reject
-            // ill-formed UTF-8 in a text string, so a value whose bytes are
-            // not valid UTF-8 (0xC0 0xAE is an overlong encoding of '.')
-            // round-trips byte for byte as a string value; to_bjdata() writes
-            // the bytes unchanged, as before 3.13.0, unless
-            // JSON_STRICT_BINARY_UTF8 is enabled (see
-            // unit-binary_utf8_strict.cpp)
-            const std::vector<uint8_t> v = {'S', 'i', 2, 0xc0, 0xae};
-            json j;
-            CHECK_NOTHROW(j = json::from_bjdata(v));
-            REQUIRE(j.is_string());
-            CHECK(j.get_ref<const json::string_t&>() == std::string("\xc0\xae"));
-            CHECK_THROWS_AS(j.dump(), json::type_error&);
-            CHECK(json::from_bjdata(json::to_bjdata(j)) == j);
-
-            // the same bytes as an object key round-trip as well
-            const std::vector<uint8_t> v_key = {'{', 'i', 2, 0xc0, 0xae, 'i', 1, '}'};
-            json j_key;
-            CHECK_NOTHROW(j_key = json::from_bjdata(v_key));
-            REQUIRE(j_key.is_object());
-            CHECK(j_key.contains(std::string("\xc0\xae")));
-            CHECK(json::from_bjdata(json::to_bjdata(j_key)) == j_key);
-
-            CHECK(json::from_bjdata(json::to_bjdata(json("\xFF"))) == json("\xFF"));
-            // a truncated multi-byte sequence
-            CHECK(json::from_bjdata(json::to_bjdata(json("\xC3"))) == json("\xC3"));
-            // an encoded surrogate half (U+D800)
-            CHECK(json::from_bjdata(json::to_bjdata(json("\xED\xA0\x80"))) == json("\xED\xA0\x80"));
-            // an overlong encoding of '.'
-            CHECK(json::from_bjdata(json::to_bjdata(json("\xC0\xAF"))) == json("\xC0\xAF"));
-
-            // an object key with ill-formed UTF-8 is kept the same way
-            CHECK(json::from_bjdata(json::to_bjdata(json{{"\xFF", 1}})) == json{{"\xFF", 1}});
-        }
     }
 
     SECTION("Array Type")

tests/src/unit-bson.cpp

@@ -154,43 +154,6 @@ TEST_CASE("BSON")
 #endif
     }
 
-    SECTION("ill-formed UTF-8 (see #5529, #5651)")
-    {
-        // a BSON document {"s": "\xC0\xAE"} (0xC0 0xAE is an overlong
-        // encoding of '.'); the BSON spec does not require a decoder to
-        // reject ill-formed UTF-8 in a string value, so the reader hands the
-        // bytes back unchanged
-        const std::vector<uint8_t> v =
-        {
-            0x0F, 0x00, 0x00, 0x00, // document length
-            0x02, 's', 0x00,        // type 0x02 (string), key "s"
-            0x03, 0x00, 0x00, 0x00, // string length (including null)
-            0xc0, 0xae, 0x00,       // string content and its null terminator
-            0x00                    // document terminator
-        };
-        json j;
-        CHECK_NOTHROW(j = json::from_bson(v));
-        REQUIRE(j.is_object());
-        REQUIRE(j.contains("s"));
-        CHECK(j["s"].get_ref<const json::string_t&>() == std::string("\xc0\xae"));
-        // dump() still requires valid UTF-8 and throws for such a value
-        CHECK_THROWS_AS(j.dump(), json::type_error&);
-        // to_bson() writes the bytes back unchanged, as before 3.13.0,
-        // unless JSON_STRICT_BINARY_UTF8 is enabled (see unit-binary_utf8_strict.cpp)
-        CHECK(json::from_bson(json::to_bson(j)) == j);
-
-        CHECK(json::from_bson(json::to_bson(json{{"s", "\xFF"}})) == json{{"s", "\xFF"}});
-        // a truncated multi-byte sequence
-        CHECK(json::from_bson(json::to_bson(json{{"s", "\xC3"}})) == json{{"s", "\xC3"}});
-        // an encoded surrogate half (U+D800)
-        CHECK(json::from_bson(json::to_bson(json{{"s", "\xED\xA0\x80"}})) == json{{"s", "\xED\xA0\x80"}});
-        // an overlong encoding of '.'
-        CHECK(json::from_bson(json::to_bson(json{{"s", "\xC0\xAF"}})) == json{{"s", "\xC0\xAF"}});
-
-        // an object key with ill-formed UTF-8 is kept as well
-        CHECK(json::from_bson(json::to_bson(json{{"\xFF", 1}})) == json{{"\xFF", 1}});
-    }
-
     SECTION("lengths exceeding INT32_MAX cannot be serialized to BSON")
     {
         // out_of_range.412 is thrown from a single shared helper

tests/src/unit-cbor.cpp

@@ -1801,41 +1801,19 @@ TEST_CASE("CBOR")
             CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xA1, 0x7C, 0x01})), "[json.exception.parse_error.113] parse error at byte 2: syntax error while parsing CBOR string: expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0x7C", json::parse_error&);
         }
 
-        SECTION("ill-formed UTF-8 in string (see #5529, #5651)")
+        SECTION("invalid UTF-8 in string (see #5529)")
         {
-            // RFC 8949 §3.1 leaves it up to the decoder whether to reject
-            // ill-formed UTF-8 in a text string; this library does not, and
-            // hands the original bytes back unchanged, matching the
-            // MessagePack reader and the behavior before #5185/#5531 (not in
-            // any release)
-
             // a two-character text string (major type 3) whose bytes are not
-            // valid UTF-8 (0xC0 0xAE is an overlong encoding of '.') round-trips
+            // valid UTF-8 (0xC0 0xAE is an overlong encoding of '.') must be
-            // byte for byte as a string value
+            // rejected at decode time, matching every other kind of
-            const std::vector<uint8_t> ill_formed_value = {0x62, 0xc0, 0xae};
+            // malformed binary input, rather than only failing later when
-            json j_value;
+            // the resulting value is dumped
-            CHECK_NOTHROW(j_value = json::from_cbor(ill_formed_value));
+            json _;
-            REQUIRE(j_value.is_string());
+            CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0x62, 0xc0, 0xae})), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR string: invalid string: ill-formed UTF-8 byte", json::parse_error&);
-            CHECK(j_value.get_ref<const json::string_t&>() == std::string("\xc0\xae"));
+            CHECK(json::from_cbor(std::vector<uint8_t>({0x62, 0xc0, 0xae}), true, false).is_discarded());
-            // dump() still requires valid UTF-8 and throws for such a value,
-            // unless an error handler that replaces or ignores the bytes is
-            // passed
-            CHECK_THROWS_AS(j_value.dump(), json::type_error&);
-            // to_cbor() writes the bytes back unchanged, as before 3.13.0,
-            // unless JSON_STRICT_BINARY_UTF8 is enabled (see unit-binary_utf8_strict.cpp)
-            CHECK(json::from_cbor(json::to_cbor(j_value)) == j_value);
-
-            // the same bytes as an object key round-trip as well
-            const std::vector<uint8_t> ill_formed_key = {0xa1, 0x62, 0xc0, 0xae, 0x01};
-            json j_key;
-            CHECK_NOTHROW(j_key = json::from_cbor(ill_formed_key));
-            REQUIRE(j_key.is_object());
-            CHECK(j_key.contains(std::string("\xc0\xae")));
-            CHECK(json::from_cbor(json::to_cbor(j_key)) == j_key);
 
             // a CBOR byte string (major type 2) with the very same bytes is
             // NOT text and must still be accepted as-is
-            json _;
             CHECK_NOTHROW(_ = json::from_cbor(std::vector<uint8_t>({0x42, 0xc0, 0xae})));
             CHECK(_ == json::binary(std::vector<std::uint8_t>({0xc0, 0xae})));
 
@@ -1844,47 +1822,17 @@ TEST_CASE("CBOR")
             CHECK(json::from_cbor(json::to_cbor(j)) == j);
         }
 
-        SECTION("to_cbor keeps ill-formed UTF-8 (see #5651)")
+        SECTION("invalid UTF-8 in indefinite-length string")
-        {
-            // to_cbor() writes the bytes unchanged, as before 3.13.0, unless
-            // JSON_STRICT_BINARY_UTF8 is enabled (see
-            // unit-binary_utf8_strict.cpp); from_cbor() reads them back as is
-            CHECK(json::from_cbor(json::to_cbor(json("\xFF"))) == json("\xFF"));
-            // a truncated multi-byte sequence
-            CHECK(json::from_cbor(json::to_cbor(json("\xC3"))) == json("\xC3"));
-            // an encoded surrogate half (U+D800)
-            CHECK(json::from_cbor(json::to_cbor(json("\xED\xA0\x80"))) == json("\xED\xA0\x80"));
-            // an overlong encoding of '.'
-            CHECK(json::from_cbor(json::to_cbor(json("\xC0\xAF"))) == json("\xC0\xAF"));
-
-            // an object key with ill-formed UTF-8 is kept the same way
-            CHECK(json::from_cbor(json::to_cbor(json{{"\xFF", 1}})) == json{{"\xFF", 1}});
-
-            // binary values are not text and are unaffected
-            CHECK_NOTHROW(json::to_cbor(json::binary(std::vector<std::uint8_t>({0xFF}))));
-        }
-
-        SECTION("ill-formed UTF-8 in indefinite-length string")
         {
             json _;
 
-            // the chunks are concatenated as is, without checking that each
+            // every chunk must be valid UTF-8 on its own (RFC 8949, Section
-            // chunk is valid UTF-8 on its own (RFC 8949, Section 3.2.3), so
+            // 3.2.3), so a code point split across two chunks is rejected
-            // a code point split across two chunks yields a valid string
+            CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0x7f, 0x61, 0xc3, 0x61, 0xa9, 0xff})), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR string: invalid string: ill-formed UTF-8 byte", json::parse_error&);
-            CHECK_NOTHROW(_ = json::from_cbor(std::vector<uint8_t>({0x7f, 0x61, 0xc3, 0x61, 0xa9, 0xff})));
+            CHECK(json::from_cbor(std::vector<uint8_t>({0x7f, 0x61, 0xc3, 0x61, 0xa9, 0xff}), true, false).is_discarded());
-            CHECK(_ == "\xc3\xa9");
-            CHECK(_.dump() == "\"\xc3\xa9\"");
 
-            // a truncated code point is kept as is
+            // an ill-formed later chunk is rejected after valid ones
-            CHECK_NOTHROW(_ = json::from_cbor(std::vector<uint8_t>({0x7f, 0x61, 0xc3, 0xff})));
+            CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0x7f, 0x62, 0xc3, 0xa9, 0x62, 0xc0, 0xae, 0xff})), "[json.exception.parse_error.113] parse error at byte 7: syntax error while parsing CBOR string: invalid string: ill-formed UTF-8 byte", json::parse_error&);
-            CHECK(_ == "\xc3");
-            CHECK_THROWS_AS(_.dump(), json::type_error&);
-            CHECK(json::from_cbor(json::to_cbor(_)) == _);
-
-            // an ill-formed later chunk is kept after valid ones
-            CHECK_NOTHROW(_ = json::from_cbor(std::vector<uint8_t>({0x7f, 0x62, 0xc3, 0xa9, 0x62, 0xc0, 0xae, 0xff})));
-            CHECK(_ == "\xc3\xa9\xc0\xae");
-            CHECK_THROWS_AS(_.dump(), json::type_error&);
 
             // valid multi-byte chunks are accepted
             CHECK(json::from_cbor(std::vector<uint8_t>({0x7f, 0x62, 0xc3, 0xa9, 0x62, 0xc3, 0xb6, 0xff})) == "\xc3\xa9\xc3\xb6");
@@ -1892,6 +1840,9 @@ TEST_CASE("CBOR")
 
         SECTION("many chunks in indefinite-length string")
         {
+            // only the newly read chunk is validated, not the whole string
+            // collected so far; validating the latter made this input take
+            // quadratic time (about ten seconds for 100000 chunks)
             constexpr std::size_t chunks = 100000;
             std::vector<uint8_t> v{0x7f};
             for (std::size_t i = 0; i < chunks; ++i)

tests/src/unit-conversions.cpp

@@ -430,6 +430,37 @@ TEST_CASE("value conversion")
             CHECK(std::equal(std::begin(nbs[0][0][0]), std::end(nbs[1][1][1]), std::begin(nbs2[0][0][0])));
         }
 
+        SECTION("built-in arrays: 5D")
+        {
+            // NOLINTBEGIN(misc-const-correctness,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+            const int nbs[1][1][1][2][2] = {{{{{0, 1}, {2, 3}}}}};
+            int nbs2[1][1][1][2][2] = {{{{{0, 0}, {0, 0}}}}};
+            // NOLINTEND(misc-const-correctness,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+
+            const json j2 = nbs;
+            j2.get_to(nbs2);
+            CHECK(std::equal(std::begin(nbs[0][0][0][0]), std::end(nbs[0][0][0][1]), std::begin(nbs2[0][0][0][0])));
+        }
+
+        SECTION("built-in arrays: mismatched shape")
+        {
+            // NOLINTBEGIN(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+            int nbs2[2][3] = {{0, 0, 0}, {0, 0, 0}};
+            // NOLINTEND(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
+
+            SECTION("not an array")
+            {
+                const json j2 = 42;
+                CHECK_THROWS_WITH_AS(j2.get_to(nbs2), "[json.exception.type_error.304] cannot use at() with number", json::type_error&);
+            }
+
+            SECTION("too few elements")
+            {
+                const json j2 = {{0, 1, 2}};
+                CHECK_THROWS_WITH_AS(j2.get_to(nbs2), "[json.exception.out_of_range.401] array index 1 is out of range", json::out_of_range&);
+            }
+        }
+
         SECTION("std::deque<json>")
         {
             std::deque<json> a{"previous", "value"};
@@ -1736,6 +1767,34 @@ NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(StrictTaskState,
     {STRICT_TS_COMPLETED, "completed"},
 })
 
+// regression test for #5708 item 2: NLOHMANN_JSON_SERIALIZE_ENUM_STRICT must not rely on
+// unqualified lookup of a helper name that a user's own namespace may also declare
+namespace ns_with_colliding_name
+{
+// NOLINTNEXTLINE(misc-use-internal-linkage) - used to shadow the library's internal helper name
+inline void templated_json_throw(int /*unused*/) {}
+
+enum class colliding_enum { a, b };
+
+// NOLINTNEXTLINE(misc-use-internal-linkage,misc-const-correctness,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays) - false positive
+NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(colliding_enum,
+{
+    {colliding_enum::a, "a"},
+    {colliding_enum::b, "b"}
+})
+} // namespace ns_with_colliding_name
+
+TEST_CASE("NLOHMANN_JSON_SERIALIZE_ENUM_STRICT in a namespace with a colliding name")
+{
+    using ns_with_colliding_name::colliding_enum;
+
+    CHECK(json(colliding_enum::a) == "a");
+    CHECK(colliding_enum::b == json("b"));
+
+    json _;
+    CHECK_THROWS_WITH_AS(_ = json("nope").get<colliding_enum>(), "[json.exception.out_of_range.410] enum value out of range for colliding_enum: \"nope\"", json::out_of_range&);
+}
+
 TEST_CASE("Strict JSON to enum mapping")
 {
     SECTION("enum class")

tests/src/unit-element_access2.cpp

@@ -516,6 +516,16 @@ TEST_CASE_TEMPLATE("element access 2", Json, nlohmann::json, nlohmann::ordered_j
                     CHECK(j_array.value("/-"_json_pointer, 42) == 42);
                     CHECK(j_array_const.value("/-"_json_pointer, 42) == 42);
 
+                    // Test an index that is syntactically valid but exceeds size_type, and one
+                    // with a trailing non-digit: both must yield the default value rather than
+                    // throw, even with exceptions disabled (regression test for #5708 item 4 /
+                    // #5672: get_checked_or_null() no longer relies on a JSON_TRY/
+                    // JSON_INTERNAL_CATCH around array_index() to turn these into "not found")
+                    CHECK(j_array.value("/18446744073709551615"_json_pointer, 42) == 42);
+                    CHECK(j_array_const.value("/18446744073709551615"_json_pointer, 42) == 42);
+                    CHECK(j_array.value("/1a"_json_pointer, 42) == 42);
+                    CHECK(j_array_const.value("/1a"_json_pointer, 42) == 42);
+
 #if !defined(JSON_NOEXCEPTION)
                     // Test malformed index (non-numeric) throws parse_error
                     CHECK_THROWS_WITH_AS(j_array.value("/foo"_json_pointer, 1), "[json.exception.parse_error.109] parse error: array index 'foo' is not a number", typename Json::parse_error&);

tests/src/unit-msgpack.cpp

@@ -1540,39 +1540,19 @@ TEST_CASE("MessagePack")
             CHECK_THROWS_WITH_AS(_ = json::from_msgpack(std::vector<uint8_t>({0x81})), "[json.exception.parse_error.110] parse error at byte 2: syntax error while parsing MessagePack string: unexpected end of input", json::parse_error&);
         }
 
-        SECTION("ill-formed UTF-8 in string (see #5529, #5651)")
+        SECTION("invalid UTF-8 in string (see #5529)")
         {
-            // the MessagePack specification explicitly allows a str object to
-            // contain a byte sequence that is not valid UTF-8 and expects a
-            // deserializer to hand the original bytes back unchanged; this
-            // library follows that, unlike CBOR/UBJSON/BJData/BSON, whose
-            // specifications require text strings to be valid UTF-8
-
             // a fixstr of length 2 (0xA0 | 2) whose bytes are not valid UTF-8
-            // (0xC0 0xAE is an overlong encoding of '.') round-trips byte for
+            // (0xC0 0xAE is an overlong encoding of '.') must be rejected at
-            // byte as a string value
+            // decode time, matching every other kind of malformed binary
-            const std::vector<uint8_t> ill_formed_value = {0xa2, 0xc0, 0xae};
+            // input, rather than only failing later when the resulting
-            json j_value;
+            // value is dumped
-            CHECK_NOTHROW(j_value = json::from_msgpack(ill_formed_value));
+            json _;
-            REQUIRE(j_value.is_string());
+            CHECK_THROWS_WITH_AS(_ = json::from_msgpack(std::vector<uint8_t>({0xa2, 0xc0, 0xae})), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing MessagePack string: invalid string: ill-formed UTF-8 byte", json::parse_error&);
-            CHECK(j_value.get_ref<const json::string_t&>() == std::string("\xc0\xae"));
+            CHECK(json::from_msgpack(std::vector<uint8_t>({0xa2, 0xc0, 0xae}), true, false).is_discarded());
-            CHECK(json::from_msgpack(json::to_msgpack(j_value)) == j_value);
-            // dump() still requires valid UTF-8 and throws for such a value,
-            // unless an error handler that replaces or ignores the bytes is
-            // passed
-            CHECK_THROWS_AS(j_value.dump(), json::type_error&);
-
-            // the same bytes as an object key round-trip as well
-            const std::vector<uint8_t> ill_formed_key = {0x81, 0xa2, 0xc0, 0xae, 0x01};
-            json j_key;
-            CHECK_NOTHROW(j_key = json::from_msgpack(ill_formed_key));
-            REQUIRE(j_key.is_object());
-            CHECK(j_key.contains(std::string("\xc0\xae")));
-            CHECK(json::from_msgpack(json::to_msgpack(j_key)) == j_key);
 
             // a MessagePack bin8 blob with the very same bytes is NOT text
             // and must still be accepted as-is
-            json _;
             CHECK_NOTHROW(_ = json::from_msgpack(std::vector<uint8_t>({0xc4, 0x02, 0xc0, 0xae})));
             CHECK(_ == json::binary(std::vector<std::uint8_t>({0xc0, 0xae})));
 

tests/src/unit-type_traits.cpp

@@ -10,10 +10,14 @@
 
 #if JSON_TEST_USING_MULTIPLE_HEADERS
     #include <nlohmann/detail/meta/type_traits.hpp>
+    #include <nlohmann/ordered_map.hpp>
 #else
     #include <nlohmann/json.hpp>
 #endif
 
+#include <map>
+#include <string>
+
 TEST_CASE("type traits")
 {
     SECTION("is_c_string")
@@ -83,4 +87,12 @@ TEST_CASE("type traits")
             }
         }
     }
+
+    SECTION("is_ordered_map")
+    {
+        using nlohmann::detail::is_ordered_map;
+
+        CHECK(is_ordered_map<nlohmann::ordered_map<std::string, int>>::value);
+        CHECK_FALSE(is_ordered_map<std::map<std::string, int>>::value);
+    }
 }

tests/src/unit-ubjson.cpp

@@ -2505,43 +2505,6 @@ TEST_CASE("Universal Binary JSON Specification Examples 1")
             CHECK(json::to_ubjson(j) == v);
             CHECK(json::from_ubjson(v) == j);
         }
-
-        SECTION("ill-formed UTF-8 (see #5529, #5651)")
-        {
-            // none of the binary format specs requires a decoder to reject
-            // ill-formed UTF-8 in a text string, so a value whose bytes are
-            // not valid UTF-8 (0xC0 0xAE is an overlong encoding of '.')
-            // round-trips byte for byte as a string value; to_ubjson() writes
-            // the bytes unchanged, as before 3.13.0, unless
-            // JSON_STRICT_BINARY_UTF8 is enabled (see
-            // unit-binary_utf8_strict.cpp)
-            const std::vector<uint8_t> v = {'S', 'i', 2, 0xc0, 0xae};
-            json j;
-            CHECK_NOTHROW(j = json::from_ubjson(v));
-            REQUIRE(j.is_string());
-            CHECK(j.get_ref<const json::string_t&>() == std::string("\xc0\xae"));
-            CHECK_THROWS_AS(j.dump(), json::type_error&);
-            CHECK(json::from_ubjson(json::to_ubjson(j)) == j);
-
-            // the same bytes as an object key round-trip as well
-            const std::vector<uint8_t> v_key = {'{', 'i', 2, 0xc0, 0xae, 'i', 1, '}'};
-            json j_key;
-            CHECK_NOTHROW(j_key = json::from_ubjson(v_key));
-            REQUIRE(j_key.is_object());
-            CHECK(j_key.contains(std::string("\xc0\xae")));
-            CHECK(json::from_ubjson(json::to_ubjson(j_key)) == j_key);
-
-            CHECK(json::from_ubjson(json::to_ubjson(json("\xFF"))) == json("\xFF"));
-            // a truncated multi-byte sequence
-            CHECK(json::from_ubjson(json::to_ubjson(json("\xC3"))) == json("\xC3"));
-            // an encoded surrogate half (U+D800)
-            CHECK(json::from_ubjson(json::to_ubjson(json("\xED\xA0\x80"))) == json("\xED\xA0\x80"));
-            // an overlong encoding of '.'
-            CHECK(json::from_ubjson(json::to_ubjson(json("\xC0\xAF"))) == json("\xC0\xAF"));
-
-            // an object key with ill-formed UTF-8 is kept the same way
-            CHECK(json::from_ubjson(json::to_ubjson(json{{"\xFF", 1}})) == json{{"\xFF", 1}});
-        }
     }
 
     SECTION("Array Type")