Suppress a clang-tidy false positive on an intentional defensive copy

performance-unnecessary-copy-initialization suggests copy_for_patch
could be a reference since it's never modified -- but the copy is the
point: it guards against a hypothetical regression where patch()
mutates its receiver, which a reference could never catch (the
follow-up assertion would just compare `original` to itself).

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

.github/workflows/ubuntu.yml

@@ -100,7 +100,7 @@ jobs:
     container: ubuntu:focal
     strategy:
       matrix:
-        target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls]
+        target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls, ci_test_disableenumserialization, ci_test_skiplibraryversioncheck]
     steps:
       - name: Install build-essential
         run: apt-get update ; apt-get install -y build-essential unzip wget git libssl-dev

cmake/ci.cmake

@@ -242,6 +242,40 @@ add_custom_target(ci_test_noglobaludls
     COMMENT "Compile and test with global UDLs disabled"
 )
 
+###############################################################################
+# Disable enum serialization.
+###############################################################################
+
+add_custom_target(ci_test_disableenumserialization
+    COMMAND ${CMAKE_COMMAND}
+    -DCMAKE_BUILD_TYPE=Debug -GNinja
+    -DJSON_BuildTests=ON -DJSON_FastTests=ON -DJSON_DisableEnumSerialization=ON
+    -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_disableenumserialization
+    COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_disableenumserialization
+    COMMAND cd ${PROJECT_BINARY_DIR}/build_disableenumserialization && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
+    COMMENT "Compile and test with enum serialization disabled"
+)
+
+###############################################################################
+# Skip the multiple-inclusion library version check.
+###############################################################################
+
+# tests/src/skip_library_version_check.cpp deliberately simulates a scenario
+# (mixing two differently-versioned inclusions of the library in one
+# translation unit) that unavoidably triggers the compiler's own "macro
+# redefined" warning, so -- unlike the ci_test_* targets above -- it is
+# compiled directly here, with a modest warning set, instead of being folded
+# into the library's own -Weverything/-Werror unit test matrix.
+add_custom_target(ci_test_skiplibraryversioncheck
+    COMMAND ${CMAKE_COMMAND} -E make_directory ${PROJECT_BINARY_DIR}/skip_library_version_check
+    COMMAND ${CMAKE_CXX_COMPILER} -std=c++11 -Wall -Wextra
+        -I${PROJECT_SOURCE_DIR}/include
+        ${PROJECT_SOURCE_DIR}/tests/src/skip_library_version_check.cpp
+        -o ${PROJECT_BINARY_DIR}/skip_library_version_check/skip_library_version_check
+    COMMAND ${PROJECT_BINARY_DIR}/skip_library_version_check/skip_library_version_check
+    COMMENT "Compile and run a translation unit simulating a mismatched library version, with JSON_SKIP_LIBRARY_VERSION_CHECK defined"
+)
+
 ###############################################################################
 # Coverage.
 ###############################################################################

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

@@ -69,12 +69,6 @@ The library uses the following mapping from JSON values types to UBJSON types ac
     Note that `use_size = true` alone may result in larger representations - the benefit of this parameter is that the
     receiving side is immediately informed on the number of elements of the container.
 
-    An array whose type marker is `Z` (null), `T` (true) or `F` (false) stores no payload at all, because the marker
-    already is the value. Its declared count is therefore the only thing that decides how much memory the receiving side
-    allocates, and a handful of bytes can describe billions of elements. `from_ubjson` rejects such an array with
-    [`out_of_range.408`](../../home/exceptions.md#jsonexceptionout_of_range408) when the count exceeds 1,048,576, and
-    `to_ubjson` writes longer arrays of these types without the annotation, so any value it produces can be read back.
-
 !!! info "Binary values"
 
     If the JSON data contains the binary type, the value stored is a list of integers, as suggested by the UBJSON

docs/mkdocs/docs/home/exceptions.md

@@ -868,12 +868,6 @@ The size of an array or object in a [binary format](../features/binary_formats/i
 the size following `#` for [UBJSON](../features/binary_formats/ubjson.md)/[BJData](../features/binary_formats/bjdata.md),
 or the encoded length for [CBOR](../features/binary_formats/cbor.md).
 
-The exception is also thrown for a [UBJSON](../features/binary_formats/ubjson.md) array of a type that is encoded by its
-marker alone (`Z`, `T` or `F`) whose declared count exceeds 1,048,576. Such an array has no payload, so its count alone
-decides how much memory is allocated, and a handful of bytes would otherwise describe billions of values.
-[`to_ubjson`](../api/basic_json/to_ubjson.md) writes longer arrays of these types without the size and type annotation,
-so any value it produces can still be read back.
-
 !!! failure "Example messages"
 
     ```
@@ -885,9 +879,6 @@ so any value it produces can still be read back.
     ```
     [json.exception.out_of_range.408] syntax error while parsing CBOR size: excessive map size
     ```
-    ```
-    [json.exception.out_of_range.408] syntax error while parsing UBJSON size: excessive array size
-    ```
 
 ### json.exception.out_of_range.409
 

include/nlohmann/detail/input/binary_reader.hpp

@@ -58,26 +58,6 @@ inline bool little_endianness(int num = 1) noexcept
     return *reinterpret_cast<char*>(&num) == 1;
 }
 
-/*!
-@brief largest element count accepted for a UBJSON container of a valueless type
-
-An element of type 'Z' (null), 'T' (true) or 'F' (false) is encoded by its
-type marker alone, so an optimized container of one of those types has no
-payload at all and its declared count is the only thing that decides how much
-is allocated: `[$Z#L` followed by a large count turns some ten bytes of input
-into that many values (see #2793, which reports 35 GB and 150 seconds). Every
-other type costs at least one byte per element and is bounded by the end of
-the input.
-
-This is a sanity bound rather than a security boundary, and it is far above
-any container met in practice. @ref binary_writer falls back to the
-unoptimized encoding for longer containers, so that a value serialized by
-this library can always be read back.
-
-@sa https://github.com/nlohmann/json/issues/2793
-*/
-JSON_INLINE_VARIABLE constexpr std::size_t max_valueless_container_size = 1 << 20;
-
 ///////////////////
 // binary reader //
 ///////////////////
@@ -1016,21 +996,23 @@ class binary_reader
     }
 
     /*!
-    @brief reads a definite-length CBOR string
+    @brief reads a CBOR string
 
-    Reads everything @ref get_cbor_string accepts except the indefinite-length
-    form, which that function handles itself. The bytes are appended to @a
-    result, so consecutive chunks of an indefinite-length string can be read
-    into the same string.
+    This function first reads starting bytes to determine the expected
+    string length and then copies this number of bytes into a string.
+    Additionally, CBOR's strings with indefinite lengths are supported.
 
-    @param[out] result  string the bytes are appended to
+    @param[out] result  created string
 
     @return whether string creation completed
-
-    @pre @a current is not EOF
     */
-    bool get_cbor_string_chunk(string_t& result)
+    bool get_cbor_string(string_t& result)
     {
+        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "string")))
+        {
+            return false;
+        }
+
         switch (current)
         {
             // UTF-8 string (0x00..0x17 bytes follow)
@@ -1086,6 +1068,20 @@ class binary_reader
                 return get_number(input_format_t::cbor, len) && get_string(input_format_t::cbor, len, result);
             }
 
+            case 0x7F: // UTF-8 string (indefinite length)
+            {
+                while (get() != 0xFF)
+                {
+                    string_t chunk;
+                    if (!get_cbor_string(chunk))
+                    {
+                        return false;
+                    }
+                    result.append(chunk);
+                }
+                return true;
+            }
+
             default:
             {
                 auto last_token = get_token_string();
@@ -1096,82 +1092,23 @@ class binary_reader
     }
 
     /*!
-    @brief reads a CBOR string
+    @brief reads a CBOR byte array
 
     This function first reads starting bytes to determine the expected
-    string length and then copies this number of bytes into a string.
-    Additionally, CBOR's strings with indefinite lengths are supported.
+    byte array length and then copies this number of bytes into the byte array.
+    Additionally, CBOR's byte arrays with indefinite lengths are supported.
 
-    @param[out] result  created string
-
-    @return whether string creation completed
-    */
-    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,
-        // but this reader has always accepted it, so the open levels are
-        // counted instead of recursed through, which overflowed the stack for
-        // an input of repeated 0x7F bytes (see #5104). Every chunk is appended
-        // to the same result, so no per-level state is needed.
-        std::size_t open = 0;
-
-        while (true)
-        {
-            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "string")))
-            {
-                return false;
-            }
-
-            if (current == 0x7F) // UTF-8 string (indefinite length)
-            {
-                ++open;
-                get();
-                continue;
-            }
-
-            // a break marker closes the innermost indefinite-length string;
-            // outside of one it is not a string and falls through to the error
-            if (open != 0 && current == 0xFF)
-            {
-                if (--open == 0)
-                {
-                    return true;
-                }
-                get();
-                continue;
-            }
-
-            if (JSON_HEDLEY_UNLIKELY(!get_cbor_string_chunk(result)))
-            {
-                return false;
-            }
-
-            if (open == 0)
-            {
-                return true;
-            }
-
-            get();
-        }
-    }
-
-    /*!
-    @brief reads a definite-length CBOR byte array
-
-    Reads everything @ref get_cbor_binary accepts except the indefinite-length
-    form, which that function handles itself. The bytes are appended to @a
-    result, so consecutive chunks of an indefinite-length byte array can be
-    read into the same byte array.
-
-    @param[out] result  byte array the bytes are appended to
+    @param[out] result  created byte array
 
     @return whether byte array creation completed
-
-    @pre @a current is not EOF
     */
-    bool get_cbor_binary_chunk(binary_t& result)
+    bool get_cbor_binary(binary_t& result)
     {
+        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "binary")))
+        {
+            return false;
+        }
+
         switch (current)
         {
             // Binary data (0x00..0x17 bytes follow)
@@ -1231,6 +1168,20 @@ class binary_reader
                        get_binary(input_format_t::cbor, len, result);
             }
 
+            case 0x5F: // Binary data (indefinite length)
+            {
+                while (get() != 0xFF)
+                {
+                    binary_t chunk;
+                    if (!get_cbor_binary(chunk))
+                    {
+                        return false;
+                    }
+                    result.insert(result.end(), chunk.begin(), chunk.end());
+                }
+                return true;
+            }
+
             default:
             {
                 auto last_token = get_token_string();
@@ -1240,63 +1191,6 @@ class binary_reader
         }
     }
 
-    /*!
-    @brief reads a CBOR byte array
-
-    This function first reads starting bytes to determine the expected
-    byte array length and then copies this number of bytes into the byte array.
-    Additionally, CBOR's byte arrays with indefinite lengths are supported.
-
-    @param[out] result  created byte array
-
-    @return whether byte array creation completed
-    */
-    bool get_cbor_binary(binary_t& result)
-    {
-        // the open indefinite-length byte arrays are counted rather than
-        // recursed through, for the reason given in @ref get_cbor_string
-        std::size_t open = 0;
-
-        while (true)
-        {
-            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "binary")))
-            {
-                return false;
-            }
-
-            if (current == 0x5F) // Binary data (indefinite length)
-            {
-                ++open;
-                get();
-                continue;
-            }
-
-            // a break marker closes the innermost indefinite-length byte
-            // array; outside of one it falls through to the error below
-            if (open != 0 && current == 0xFF)
-            {
-                if (--open == 0)
-                {
-                    return true;
-                }
-                get();
-                continue;
-            }
-
-            if (JSON_HEDLEY_UNLIKELY(!get_cbor_binary_chunk(result)))
-            {
-                return false;
-            }
-
-            if (open == 0)
-            {
-                return true;
-            }
-
-            get();
-        }
-    }
-
     /*!
     @brief narrow a definite CBOR array/map length to std::size_t
 
@@ -2497,12 +2391,7 @@ class binary_reader
     {
         result.first = npos; // size
         result.second = 0; // type
-        // seed the flag with the caller's context: inside an ndarray dimension
-        // vector another ndarray is not allowed, and get_ubjson_size_value()
-        // rejects it up front instead of reading it and reporting afterwards.
-        // Seeding it with `false` made every '#' of a "[#[#[..." chain descend
-        // another level, which overflowed the stack (see #5104).
-        bool is_ndarray = inside_ndarray;
+        bool is_ndarray = false;
 
         get_ignore_noop();
 
@@ -2535,11 +2424,13 @@ class binary_reader
             }
 
             const bool is_error = get_ubjson_size_value(result.first, is_ndarray);
-            // an ndarray was read here only if the flag flipped; when it was
-            // seeded true, get_ubjson_size_value() already rejected the nested
-            // dimension vector
-            if (input_format == input_format_t::bjdata && is_ndarray && !inside_ndarray)
+            if (input_format == input_format_t::bjdata && is_ndarray)
             {
+                if (inside_ndarray)
+                {
+                    return sax->parse_error(chars_read, get_token_string(), parse_error::create(112, chars_read,
+                                            exception_message(input_format, "ndarray can not be recursive", "size"), nullptr));
+                }
                 result.second |= (1 << 8); // use bit 8 to indicate ndarray, all UBJSON and BJData markers should be ASCII letters
             }
             return is_error;
@@ -2548,7 +2439,7 @@ class binary_reader
         if (current == '#')
         {
             const bool is_error = get_ubjson_size_value(result.first, is_ndarray);
-            if (input_format == input_format_t::bjdata && is_ndarray && !inside_ndarray)
+            if (input_format == input_format_t::bjdata && is_ndarray)
             {
                 return sax->parse_error(chars_read, get_token_string(), parse_error::create(112, chars_read,
                                         exception_message(input_format, "ndarray requires both type and size", "size"), nullptr));
@@ -2819,17 +2710,6 @@ class binary_reader
 
         if (size_and_type.first != npos)
         {
-            // reading an element of a valueless type consumes no input, so the
-            // declared count alone decides how much is allocated; the check is
-            // made before the start event so that no container is opened that
-            // is then abandoned. See @ref max_valueless_container_size.
-            if (JSON_HEDLEY_UNLIKELY((size_and_type.second == 'Z' || size_and_type.second == 'T' || size_and_type.second == 'F')
-                                     && size_and_type.first > max_valueless_container_size))
-            {
-                return sax->parse_error(chars_read, get_token_string(), out_of_range::create(408,
-                                        exception_message(input_format, "excessive array size", "size"), nullptr));
-            }
-
             if (JSON_HEDLEY_UNLIKELY(!sax->start_array(size_and_type.first)))
             {
                 return false;

include/nlohmann/detail/output/binary_writer.hpp

@@ -826,17 +826,7 @@ class binary_writer
 
                     std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
 
-                    // an optimized array of a valueless type carries no payload, so a
-                    // reader has nothing but the declared count to bound the allocation
-                    // by and refuses an excessive one. Write the unoptimized form for
-                    // those, at one byte per element, so the result can be read back.
-                    // Objects are not affected: every element is preceded by its key.
-                    const bool valueless_type = (first_prefix == 'Z' || first_prefix == 'T' || first_prefix == 'F');
-                    const bool excessive_valueless = valueless_type
-                                                     && j.m_data.m_value.array->size() > detail::max_valueless_container_size;
-
-                    if (same_prefix && !excessive_valueless
-                            && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
+                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
                     {
                         prefix_required = false;
                         oa->write_character(to_char_type('$'));

include/nlohmann/json.hpp

@@ -4473,11 +4473,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in CBOR format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4493,11 +4490,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     template<typename T>
@@ -4522,11 +4516,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = i.get();
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
         // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in MessagePack format
@@ -4540,11 +4531,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::msgpack, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in MessagePack format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4559,11 +4547,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::msgpack, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     template<typename T>
@@ -4586,11 +4571,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = i.get();
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
         // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in UBJSON format
@@ -4604,11 +4586,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::ubjson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in UBJSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4623,11 +4602,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::ubjson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     template<typename T>
@@ -4650,11 +4626,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = i.get();
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
         // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in BJData format
@@ -4668,11 +4641,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::bjdata, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata).sax_parse(input_format_t::bjdata, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in BJData format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4687,11 +4657,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::bjdata, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata).sax_parse(input_format_t::bjdata, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in BSON format
@@ -4705,11 +4672,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::bson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in BSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4724,11 +4688,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::bson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     template<typename T>
@@ -4751,11 +4712,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = i.get();
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
         // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
     /// @}
 

single_include/nlohmann/json.hpp

@@ -10745,26 +10745,6 @@ inline bool little_endianness(int num = 1) noexcept
     return *reinterpret_cast<char*>(&num) == 1;
 }
 
-/*!
-@brief largest element count accepted for a UBJSON container of a valueless type
-
-An element of type 'Z' (null), 'T' (true) or 'F' (false) is encoded by its
-type marker alone, so an optimized container of one of those types has no
-payload at all and its declared count is the only thing that decides how much
-is allocated: `[$Z#L` followed by a large count turns some ten bytes of input
-into that many values (see #2793, which reports 35 GB and 150 seconds). Every
-other type costs at least one byte per element and is bounded by the end of
-the input.
-
-This is a sanity bound rather than a security boundary, and it is far above
-any container met in practice. @ref binary_writer falls back to the
-unoptimized encoding for longer containers, so that a value serialized by
-this library can always be read back.
-
-@sa https://github.com/nlohmann/json/issues/2793
-*/
-JSON_INLINE_VARIABLE constexpr std::size_t max_valueless_container_size = 1 << 20;
-
 ///////////////////
 // binary reader //
 ///////////////////
@@ -11703,21 +11683,23 @@ class binary_reader
     }
 
     /*!
-    @brief reads a definite-length CBOR string
+    @brief reads a CBOR string
 
-    Reads everything @ref get_cbor_string accepts except the indefinite-length
-    form, which that function handles itself. The bytes are appended to @a
-    result, so consecutive chunks of an indefinite-length string can be read
-    into the same string.
+    This function first reads starting bytes to determine the expected
+    string length and then copies this number of bytes into a string.
+    Additionally, CBOR's strings with indefinite lengths are supported.
 
-    @param[out] result  string the bytes are appended to
+    @param[out] result  created string
 
     @return whether string creation completed
-
-    @pre @a current is not EOF
     */
-    bool get_cbor_string_chunk(string_t& result)
+    bool get_cbor_string(string_t& result)
     {
+        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "string")))
+        {
+            return false;
+        }
+
         switch (current)
         {
             // UTF-8 string (0x00..0x17 bytes follow)
@@ -11773,6 +11755,20 @@ class binary_reader
                 return get_number(input_format_t::cbor, len) && get_string(input_format_t::cbor, len, result);
             }
 
+            case 0x7F: // UTF-8 string (indefinite length)
+            {
+                while (get() != 0xFF)
+                {
+                    string_t chunk;
+                    if (!get_cbor_string(chunk))
+                    {
+                        return false;
+                    }
+                    result.append(chunk);
+                }
+                return true;
+            }
+
             default:
             {
                 auto last_token = get_token_string();
@@ -11783,82 +11779,23 @@ class binary_reader
     }
 
     /*!
-    @brief reads a CBOR string
+    @brief reads a CBOR byte array
 
     This function first reads starting bytes to determine the expected
-    string length and then copies this number of bytes into a string.
-    Additionally, CBOR's strings with indefinite lengths are supported.
+    byte array length and then copies this number of bytes into the byte array.
+    Additionally, CBOR's byte arrays with indefinite lengths are supported.
 
-    @param[out] result  created string
-
-    @return whether string creation completed
-    */
-    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,
-        // but this reader has always accepted it, so the open levels are
-        // counted instead of recursed through, which overflowed the stack for
-        // an input of repeated 0x7F bytes (see #5104). Every chunk is appended
-        // to the same result, so no per-level state is needed.
-        std::size_t open = 0;
-
-        while (true)
-        {
-            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "string")))
-            {
-                return false;
-            }
-
-            if (current == 0x7F) // UTF-8 string (indefinite length)
-            {
-                ++open;
-                get();
-                continue;
-            }
-
-            // a break marker closes the innermost indefinite-length string;
-            // outside of one it is not a string and falls through to the error
-            if (open != 0 && current == 0xFF)
-            {
-                if (--open == 0)
-                {
-                    return true;
-                }
-                get();
-                continue;
-            }
-
-            if (JSON_HEDLEY_UNLIKELY(!get_cbor_string_chunk(result)))
-            {
-                return false;
-            }
-
-            if (open == 0)
-            {
-                return true;
-            }
-
-            get();
-        }
-    }
-
-    /*!
-    @brief reads a definite-length CBOR byte array
-
-    Reads everything @ref get_cbor_binary accepts except the indefinite-length
-    form, which that function handles itself. The bytes are appended to @a
-    result, so consecutive chunks of an indefinite-length byte array can be
-    read into the same byte array.
-
-    @param[out] result  byte array the bytes are appended to
+    @param[out] result  created byte array
 
     @return whether byte array creation completed
-
-    @pre @a current is not EOF
     */
-    bool get_cbor_binary_chunk(binary_t& result)
+    bool get_cbor_binary(binary_t& result)
     {
+        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "binary")))
+        {
+            return false;
+        }
+
         switch (current)
         {
             // Binary data (0x00..0x17 bytes follow)
@@ -11918,6 +11855,20 @@ class binary_reader
                        get_binary(input_format_t::cbor, len, result);
             }
 
+            case 0x5F: // Binary data (indefinite length)
+            {
+                while (get() != 0xFF)
+                {
+                    binary_t chunk;
+                    if (!get_cbor_binary(chunk))
+                    {
+                        return false;
+                    }
+                    result.insert(result.end(), chunk.begin(), chunk.end());
+                }
+                return true;
+            }
+
             default:
             {
                 auto last_token = get_token_string();
@@ -11927,63 +11878,6 @@ class binary_reader
         }
     }
 
-    /*!
-    @brief reads a CBOR byte array
-
-    This function first reads starting bytes to determine the expected
-    byte array length and then copies this number of bytes into the byte array.
-    Additionally, CBOR's byte arrays with indefinite lengths are supported.
-
-    @param[out] result  created byte array
-
-    @return whether byte array creation completed
-    */
-    bool get_cbor_binary(binary_t& result)
-    {
-        // the open indefinite-length byte arrays are counted rather than
-        // recursed through, for the reason given in @ref get_cbor_string
-        std::size_t open = 0;
-
-        while (true)
-        {
-            if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "binary")))
-            {
-                return false;
-            }
-
-            if (current == 0x5F) // Binary data (indefinite length)
-            {
-                ++open;
-                get();
-                continue;
-            }
-
-            // a break marker closes the innermost indefinite-length byte
-            // array; outside of one it falls through to the error below
-            if (open != 0 && current == 0xFF)
-            {
-                if (--open == 0)
-                {
-                    return true;
-                }
-                get();
-                continue;
-            }
-
-            if (JSON_HEDLEY_UNLIKELY(!get_cbor_binary_chunk(result)))
-            {
-                return false;
-            }
-
-            if (open == 0)
-            {
-                return true;
-            }
-
-            get();
-        }
-    }
-
     /*!
     @brief narrow a definite CBOR array/map length to std::size_t
 
@@ -13184,12 +13078,7 @@ class binary_reader
     {
         result.first = npos; // size
         result.second = 0; // type
-        // seed the flag with the caller's context: inside an ndarray dimension
-        // vector another ndarray is not allowed, and get_ubjson_size_value()
-        // rejects it up front instead of reading it and reporting afterwards.
-        // Seeding it with `false` made every '#' of a "[#[#[..." chain descend
-        // another level, which overflowed the stack (see #5104).
-        bool is_ndarray = inside_ndarray;
+        bool is_ndarray = false;
 
         get_ignore_noop();
 
@@ -13222,11 +13111,13 @@ class binary_reader
             }
 
             const bool is_error = get_ubjson_size_value(result.first, is_ndarray);
-            // an ndarray was read here only if the flag flipped; when it was
-            // seeded true, get_ubjson_size_value() already rejected the nested
-            // dimension vector
-            if (input_format == input_format_t::bjdata && is_ndarray && !inside_ndarray)
+            if (input_format == input_format_t::bjdata && is_ndarray)
             {
+                if (inside_ndarray)
+                {
+                    return sax->parse_error(chars_read, get_token_string(), parse_error::create(112, chars_read,
+                                            exception_message(input_format, "ndarray can not be recursive", "size"), nullptr));
+                }
                 result.second |= (1 << 8); // use bit 8 to indicate ndarray, all UBJSON and BJData markers should be ASCII letters
             }
             return is_error;
@@ -13235,7 +13126,7 @@ class binary_reader
         if (current == '#')
         {
             const bool is_error = get_ubjson_size_value(result.first, is_ndarray);
-            if (input_format == input_format_t::bjdata && is_ndarray && !inside_ndarray)
+            if (input_format == input_format_t::bjdata && is_ndarray)
             {
                 return sax->parse_error(chars_read, get_token_string(), parse_error::create(112, chars_read,
                                         exception_message(input_format, "ndarray requires both type and size", "size"), nullptr));
@@ -13506,17 +13397,6 @@ class binary_reader
 
         if (size_and_type.first != npos)
         {
-            // reading an element of a valueless type consumes no input, so the
-            // declared count alone decides how much is allocated; the check is
-            // made before the start event so that no container is opened that
-            // is then abandoned. See @ref max_valueless_container_size.
-            if (JSON_HEDLEY_UNLIKELY((size_and_type.second == 'Z' || size_and_type.second == 'T' || size_and_type.second == 'F')
-                                     && size_and_type.first > max_valueless_container_size))
-            {
-                return sax->parse_error(chars_read, get_token_string(), out_of_range::create(408,
-                                        exception_message(input_format, "excessive array size", "size"), nullptr));
-            }
-
             if (JSON_HEDLEY_UNLIKELY(!sax->start_array(size_and_type.first)))
             {
                 return false;
@@ -17954,17 +17834,7 @@ class binary_writer
 
                     std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
 
-                    // an optimized array of a valueless type carries no payload, so a
-                    // reader has nothing but the declared count to bound the allocation
-                    // by and refuses an excessive one. Write the unoptimized form for
-                    // those, at one byte per element, so the result can be read back.
-                    // Objects are not affected: every element is preceded by its key.
-                    const bool valueless_type = (first_prefix == 'Z' || first_prefix == 'T' || first_prefix == 'F');
-                    const bool excessive_valueless = valueless_type
-                                                     && j.m_data.m_value.array->size() > detail::max_valueless_container_size;
-
-                    if (same_prefix && !excessive_valueless
-                            && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
+                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
                     {
                         prefix_required = false;
                         oa->write_character(to_char_type('$'));
@@ -26031,11 +25901,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in CBOR format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -26051,11 +25918,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     template<typename T>
@@ -26080,11 +25944,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = i.get();
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
         // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::cbor).sax_parse(input_format_t::cbor, &sdp, strict, tag_handler); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in MessagePack format
@@ -26098,11 +25959,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::msgpack, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in MessagePack format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -26117,11 +25975,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::msgpack, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     template<typename T>
@@ -26144,11 +25999,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = i.get();
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
         // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::msgpack).sax_parse(input_format_t::msgpack, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in UBJSON format
@@ -26162,11 +26014,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::ubjson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in UBJSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -26181,11 +26030,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::ubjson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     template<typename T>
@@ -26208,11 +26054,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = i.get();
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
         // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::ubjson).sax_parse(input_format_t::ubjson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in BJData format
@@ -26226,11 +26069,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::bjdata, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata).sax_parse(input_format_t::bjdata, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in BJData format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -26245,11 +26085,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::bjdata, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bjdata).sax_parse(input_format_t::bjdata, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in BSON format
@@ -26263,11 +26100,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::bson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     /// @brief create a JSON value from an input in BSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -26282,11 +26116,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         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).sax_parse(input_format_t::bson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
 
     template<typename T>
@@ -26309,11 +26140,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = i.get();
         detail::json_sax_dom_parser<basic_json, decltype(ia)> sdp(result, allow_exceptions);
         // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-        if (!binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict)) // cppcheck-suppress[accessMoved]
-        {
-            result = value_t::discarded;
-        }
-        return result;
+        const bool res = binary_reader<decltype(ia)>(std::move(ia), input_format_t::bson).sax_parse(input_format_t::bson, &sdp, strict); // cppcheck-suppress[accessMoved]
+        return res ? result : basic_json(value_t::discarded);
     }
     /// @}
 

tests/src/skip_library_version_check.cpp

@@ -0,0 +1,61 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  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
+
+// Standalone compile-and-run check for the JSON_SKIP_LIBRARY_VERSION_CHECK
+// configuration macro, which (per #5423) was never exercised anywhere in the
+// test matrix.
+//
+// include/nlohmann/detail/abi_macros.hpp normally emits a #warning if
+// NLOHMANN_JSON_VERSION_MAJOR/MINOR/PATCH are already defined (as they would
+// be by an earlier inclusion of a different version of the library) with
+// values that mismatch the version about to be defined -- unless
+// JSON_SKIP_LIBRARY_VERSION_CHECK is defined, in which case the check (and
+// that #warning) is skipped.
+//
+// This file deliberately is not named tests/src/unit-*.cpp: it is compiled
+// directly (with a modest, non-strict warning set) by the dedicated
+// ci_test_skiplibraryversioncheck target in cmake/ci.cmake, rather than being
+// folded into the library's own -Weverything/-Werror unit test matrix. That
+// is because the scenario simulated here -- mixing two different, already
+// differently-versioned inclusions of the library in one translation unit --
+// unavoidably also triggers the *compiler's own* "macro redefined" warning,
+// independent of (and unaffected by) JSON_SKIP_LIBRARY_VERSION_CHECK, which
+// only ever silences the library's own #warning. Building this file under
+// -Weverything -Werror would therefore fail for a reason unrelated to the
+// macro under test.
+#define NLOHMANN_JSON_VERSION_MAJOR 0
+#define NLOHMANN_JSON_VERSION_MINOR 0
+#define NLOHMANN_JSON_VERSION_PATCH 0
+
+#define JSON_SKIP_LIBRARY_VERSION_CHECK 1
+
+#include <nlohmann/json.hpp>
+
+int main()
+{
+    // reaching this point at all already proves that the mismatched,
+    // pre-defined version macros above did not stop compilation -- which is
+    // exactly what JSON_SKIP_LIBRARY_VERSION_CHECK is for. The library must
+    // also still be fully usable.
+    const nlohmann::json j = {{"a", 1}, {"b", {1, 2, 3}}};
+    if (j.dump() != "{\"a\":1,\"b\":[1,2,3]}")
+    {
+        return 1;
+    }
+
+    // include/nlohmann/detail/abi_macros.hpp unconditionally (re)defines the
+    // version macros to the library's real, current version right after the
+    // (here, skipped) mismatch check, regardless of the deliberately wrong
+    // stand-in values defined above.
+    if (NLOHMANN_JSON_VERSION_MAJOR == 0 && NLOHMANN_JSON_VERSION_MINOR == 0 && NLOHMANN_JSON_VERSION_PATCH == 0)
+    {
+        return 1;
+    }
+
+    return 0;
+}

tests/src/unit-bjdata.cpp

@@ -3288,10 +3288,8 @@ TEST_CASE("BJData")
             CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR1), "[json.exception.parse_error.113] parse error at byte 6: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
             CHECK(json::from_bjdata(vR1, true, false).is_discarded());
 
-            // a dimension vector that opens another one is rejected where the
-            // nested '[' is read, rather than after it has been descended into
             std::vector<uint8_t> const vR2 = {'[', '$', 'i', '#', '[', '#', '[', 'i', 1, ']', ']', 1};
-            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR2), "[json.exception.parse_error.113] parse error at byte 7: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
+            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR2), "[json.exception.parse_error.113] parse error at byte 11: syntax error while parsing BJData size: expected length type specification (U, i, u, I, m, l, M, L) after '#'; last byte: 0x5D", json::parse_error&);
             CHECK(json::from_bjdata(vR2, true, false).is_discarded());
 
             std::vector<uint8_t> const vR3 = {'[', '#', '[', 'i', '2', 'i', 2, ']'};
@@ -3299,7 +3297,7 @@ TEST_CASE("BJData")
             CHECK(json::from_bjdata(vR3, true, false).is_discarded());
 
             std::vector<uint8_t> const vR4 = {'[', '$', 'i', '#', '[', '$', 'i', '#', '[', 'i', 1, ']', 1};
-            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR4), "[json.exception.parse_error.113] parse error at byte 9: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
+            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR4), "[json.exception.parse_error.110] parse error at byte 14: syntax error while parsing BJData number: unexpected end of input", json::parse_error&);
             CHECK(json::from_bjdata(vR4, true, false).is_discarded());
 
             std::vector<uint8_t> const vR5 = {'[', '$', 'i', '#', '[', '[', '[', ']', ']', ']'};
@@ -3307,25 +3305,12 @@ TEST_CASE("BJData")
             CHECK(json::from_bjdata(vR5, true, false).is_discarded());
 
             std::vector<uint8_t> const vR6 = {'[', '$', 'i', '#', '[', '$', 'i', '#', '[', 'i', '2', 'i', 2, ']'};
-            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR6), "[json.exception.parse_error.113] parse error at byte 9: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
+            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vR6), "[json.exception.parse_error.112] parse error at byte 14: syntax error while parsing BJData size: ndarray can not be recursive", json::parse_error&);
             CHECK(json::from_bjdata(vR6, true, false).is_discarded());
 
             std::vector<uint8_t> const vH = {'[', 'H', '[', '#', '[', '$', 'i', '#', '[', 'i', '2', 'i', 2, ']'};
             CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vH), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
             CHECK(json::from_bjdata(vH, true, false).is_discarded());
-
-            // Every "#[" of this chain used to open another dimension vector
-            // and cost several stack frames before anything was rejected, so a
-            // long enough chain crashed the process (see #5104). The nested
-            // vector is refused where it is read, so the length is irrelevant.
-            std::vector<uint8_t> vRdeep = {'['};
-            for (std::size_t i = 0; i < 100000; ++i)
-            {
-                vRdeep.push_back('#');
-                vRdeep.push_back('[');
-            }
-            CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vRdeep), "[json.exception.parse_error.113] parse error at byte 5: syntax error while parsing BJData size: ndarray dimensional vector is not allowed", json::parse_error&);
-            CHECK(json::from_bjdata(vRdeep, true, false).is_discarded());
         }
 
         SECTION("objects")

tests/src/unit-byte_container_with_subtype.cpp

@@ -42,6 +42,39 @@ TEST_CASE("byte_container_with_subtype")
         CHECK(container.subtype() == static_cast<subtype_type>(-1));
     }
 
+    SECTION("move semantics")
+    {
+        // the rvalue-reference constructor (without a subtype) must actually move
+        // the passed-in container rather than copy it; comparing the buffer address
+        // before and after is a stronger check than just observing the source is
+        // empty afterward, since a copy-then-clear could also leave it empty
+        {
+            std::vector<std::uint8_t> bytes = {{0xCA, 0xFE, 0xBA, 0xBE}};
+            const auto* const data_ptr = bytes.data();
+
+            nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>> container(std::move(bytes));
+
+            CHECK(container.size() == 4);
+            CHECK(container.data() == data_ptr);
+            CHECK(!container.has_subtype());
+            CHECK(bytes.empty()); // NOLINT(bugprone-use-after-move,clang-analyzer-cplusplus.Move,hicpp-invalid-access-moved)
+        }
+
+        // same check for the rvalue-reference constructor that also takes a subtype
+        {
+            std::vector<std::uint8_t> bytes = {{0xCA, 0xFE, 0xBA, 0xBE}};
+            const auto* const data_ptr = bytes.data();
+
+            nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>> container(std::move(bytes), 42);
+
+            CHECK(container.size() == 4);
+            CHECK(container.data() == data_ptr);
+            CHECK(container.has_subtype());
+            CHECK(container.subtype() == 42);
+            CHECK(bytes.empty()); // NOLINT(bugprone-use-after-move,clang-analyzer-cplusplus.Move,hicpp-invalid-access-moved)
+        }
+    }
+
     SECTION("comparisons")
     {
         std::vector<std::uint8_t> const bytes = {{0xCA, 0xFE, 0xBA, 0xBE}};

tests/src/unit-cbor.cpp

@@ -2035,58 +2035,6 @@ TEST_CASE("CBOR definite length equal to the indefinite-length sentinel")
     }
 }
 
-TEST_CASE("CBOR indefinite-length strings do not recurse per chunk")
-{
-    // Reading an indefinite-length string or byte array used to call itself
-    // once per chunk, so a payload of repeated 0x7F (or 0x5F) bytes exhausted
-    // the call stack before any of the input was rejected. The open levels are
-    // counted now, and the levels below prove the reader still reads the same
-    // values and reports the same errors at the same byte offsets.
-    json _;
-
-    SECTION("many open levels are reported, not crashed on")
-    {
-        const std::vector<uint8_t> input(200000, 0x7F);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(input), "[json.exception.parse_error.110] parse error at byte 200001: syntax error while parsing CBOR string: unexpected end of input", json::parse_error&);
-        CHECK(json::from_cbor(input, true, false).is_discarded());
-    }
-
-    SECTION("many open levels are reported, not crashed on (binary)")
-    {
-        const std::vector<uint8_t> input(200000, 0x5F);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(input), "[json.exception.parse_error.110] parse error at byte 200001: syntax error while parsing CBOR binary: unexpected end of input", json::parse_error&);
-        CHECK(json::from_cbor(input, true, false).is_discarded());
-    }
-
-    SECTION("chunks are still concatenated")
-    {
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x7F, 0xFF})) == json(""));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x7F, 0x61, 0x61, 0xFF})) == json("a"));
-        // nested indefinite-length strings are concatenated across levels
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x7F, 0x7F, 0x61, 0x61, 0xFF, 0x61, 0x62, 0xFF})) == json("ab"));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x7F, 0x7F, 0x7F, 0x61, 0x7A, 0xFF, 0xFF, 0xFF})) == json("z"));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0xA1, 0x7F, 0x61, 0x61, 0xFF, 0x01})) == json({{"a", 1}}));
-    }
-
-    SECTION("chunks are still concatenated (binary)")
-    {
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x5F, 0x41, 0x61, 0xFF})) == json::binary({0x61}));
-        CHECK(json::from_cbor(std::vector<uint8_t>({0x5F, 0x5F, 0x41, 0x61, 0xFF, 0x41, 0x62, 0xFF})) == json::binary({0x61, 0x62}));
-    }
-
-    SECTION("a chunk that is not a string is still rejected")
-    {
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0x7F, 0x7F, 0x00})), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR string: expected length specification (0x60-0x7B) or indefinite string type (0x7F); last byte: 0x00", json::parse_error&);
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0x5F, 0x5F, 0x00})), "[json.exception.parse_error.113] parse error at byte 3: syntax error while parsing CBOR binary: expected length specification (0x40-0x5B) or indefinite binary array type (0x5F); last byte: 0x00", json::parse_error&);
-    }
-
-    SECTION("a break marker outside an indefinite-length string is not a string")
-    {
-        // 0xFF only closes a string that was opened; on its own it is not one
-        CHECK_THROWS_WITH_AS(_ = json::from_cbor(std::vector<uint8_t>({0xA1, 0xFF, 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: 0xFF", json::parse_error&);
-    }
-}
-
 TEST_CASE("CBOR roundtrips" * doctest::skip())
 {
     SECTION("input from flynn")

tests/src/unit-conversions.cpp

@@ -1761,6 +1761,40 @@ TEST_CASE("std::filesystem::path")
 }
 #endif
 
+// the ADL to_json overload for std::u8string only exists under the same guard
+// as std::filesystem::path support (it is otherwise only reached indirectly,
+// via std::filesystem::path::u8string()) -- mirror both #if conditions from
+// include/nlohmann/detail/conversions/to_json.hpp exactly
+#if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
+#if defined(__cpp_lib_char8_t)
+TEST_CASE("std::u8string")
+{
+    SECTION("ascii")
+    {
+        const std::u8string s = u8"Path";
+        json const j = s;
+
+        CHECK(j.template get<std::string>() == "Path");
+    }
+
+    SECTION("utf-8")
+    {
+        // use \u universal-character-names (rather than raw \x byte escapes
+        // or literal non-ASCII source bytes) to compose the multi-byte UTF-8
+        // encoding -- MSVC treats \x escapes used that way inside a u8
+        // literal as a nonstandard extension (warning C5321), which some of
+        // our CI configs promote to an error; \u is portable and produces
+        // the exact same encoded bytes without depending on the source
+        // file's encoding
+        const std::u8string s = u8"P\u011B\u0161ina";
+        json const j = s;
+
+        CHECK(j.template get<std::string>() == "P\xc4\x9b\xc5\xa1ina");
+    }
+}
+#endif
+#endif
+
 TEST_CASE("std::optional")
 {
     SECTION("null")

tests/src/unit-json_patch.cpp

@@ -672,6 +672,102 @@ TEST_CASE("JSON patch")
         }
     }
 
+    SECTION("patch_inplace")
+    {
+        SECTION("happy path: patch_inplace mirrors patch() on success")
+        {
+            // mirrors "A.5. Replacing a Value" above, but applies the patch with
+            // patch_inplace() to a mutable copy instead of using patch()'s
+            // returned copy
+            json doc = R"(
+                    {
+                        "baz": "qux",
+                        "foo": "bar"
+                    }
+                )"_json;
+
+            json const patch = R"(
+                    [
+                        { "op": "replace", "path": "/baz", "value": "boo" }
+                    ]
+                )"_json;
+
+            json const expected = R"(
+                    {
+                        "baz": "boo",
+                        "foo": "bar"
+                    }
+                )"_json;
+
+            doc.patch_inplace(patch);
+            CHECK(doc == expected);
+        }
+
+        // this test relies on the "test" operation actually throwing so the
+        // partial-application state can be observed right after the throw
+        // point; under JSON_NOEXCEPTION, JSON_THROW() calls std::abort()
+        // instead (there is no C++ exception to throw), and doctest's
+        // CHECK_THROWS_AS() is compiled out to a no-op that never even
+        // invokes the given expression (see doctest's "--no-throw" test
+        // filter, which ci_test_noexceptions passes) -- so patch()/
+        // patch_inplace() would never be called at all and the follow-up
+        // state assertions below would fail against the untouched original
+#if !defined(JSON_NOEXCEPTION)
+        SECTION("distinguishing contract vs patch(): partial application on failure")
+        {
+            // Unlike patch(), which is all-or-nothing because it applies the
+            // patch to an internal copy that is simply discarded when an
+            // exception is thrown (leaving the original untouched no matter
+            // what), patch_inplace() mutates the document it is called on
+            // directly and immediately, operation by operation. So if a JSON
+            // Patch fails partway through, whatever operations already
+            // succeeded remain applied -- the document is left in a partially
+            // patched state. This is empirically verified current behavior,
+            // not just documented intent, and is pinned here as such.
+            json const original = R"(
+                    {
+                        "baz": "qux",
+                        "foo": "bar"
+                    }
+                )"_json;
+
+            // the first operation ("replace") succeeds; the second ("test")
+            // fails because the value at "/baz" no longer (and never did)
+            // equal "not boo"
+            json const patch = R"(
+                    [
+                        { "op": "replace", "path": "/baz", "value": "boo" },
+                        { "op": "test", "path": "/baz", "value": "not boo" }
+                    ]
+                )"_json;
+
+            // patch() never modifies the object it is called on -- it always
+            // operates on (and returns) a separate copy, so the original is
+            // left completely untouched, regardless of success or failure.
+            // copy_for_patch is intentionally a real copy, not a reference
+            // to `original`: the whole point of this check is to catch a
+            // hypothetical future regression where patch() *does* mutate its
+            // receiver. Using a reference here would make the assertion
+            // below compare `original` to itself -- trivially true even if
+            // such a bug existed -- which is exactly what a static analyzer
+            // can't see when it suggests "this copy is never modified, use
+            // a reference instead".
+            json copy_for_patch = original; // NOLINT(performance-unnecessary-copy-initialization)
+            CHECK_THROWS_AS(copy_for_patch.patch(patch), json::other_error&);
+            CHECK(copy_for_patch == original);
+
+            // patch_inplace(), in contrast, already applied the successful
+            // "replace" operation to the document before the "test" operation
+            // threw -- that change is not rolled back
+            json doc = original;
+            CHECK_THROWS_AS(doc.patch_inplace(patch), json::other_error&);
+            CHECK(doc != original);
+            CHECK(doc.at("baz") == "boo");
+            CHECK(doc.at("foo") == "bar");
+        }
+#endif // !defined(JSON_NOEXCEPTION)
+    }
+
     SECTION("errors")
     {
         SECTION("unknown operation")

tests/src/unit-no-mem-leak-on-adl-serialize.cpp

@@ -70,7 +70,7 @@ TEST_CASE("check_for_mem_leak_on_adl_to_json-2")
     }
 }
 
-TEST_CASE("check_for_mem_leak_on_adl_to_json-2")
+TEST_CASE("check_for_mem_leak_on_adl_to_json-3")
 {
     try
     {

tests/src/unit-no_io_and_user_exceptions.cpp

@@ -0,0 +1,91 @@
+//     __ _____ _____ _____
+//  __|  |   __|     |   | |  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
+
+// This translation unit is a dedicated, small compile-and-run check for two
+// configuration macros that (per #5423) were never exercised anywhere in the
+// test matrix:
+// - JSON_NO_IO, which removes the library's <istream>/<ostream> support
+//   (operator<<, operator>>, and the stream-based overloads of dump()/parse())
+// - the JSON_THROW_USER / JSON_TRY_USER / JSON_CATCH_USER trio, which lets a
+//   user replace the library's internal exception handling
+//
+// Both macros are about excluding/replacing a facility the library would
+// otherwise pull in on its own, and defining one has no bearing on the other,
+// so -- to keep the test matrix small -- they are exercised together in a
+// single dedicated file instead of two.
+//
+// JSON_NO_IO requires this file itself to never rely on <iostream>/<sstream>;
+// only string-based parsing/dumping is used below.
+#define JSON_NO_IO 1
+
+// The user-supplied exception macros below are a *conforming* replacement:
+// they simply forward to the real throw/try/catch keywords (via a counter so
+// the test can assert each macro was actually invoked, not just defined), so
+// every exception-related behavior the library relies on internally --
+// including rethrowing std::out_of_range as json::out_of_range in at() --
+// keeps working exactly as it would with the library's own default macros.
+static int json_throw_user_call_count = 0; // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
+
+#define JSON_THROW_USER(exception) do { ++json_throw_user_call_count; throw exception; } while (false) // NOLINT(cppcoreguidelines-macro-usage)
+#define JSON_TRY_USER try // NOLINT(cppcoreguidelines-macro-usage)
+#define JSON_CATCH_USER(exception) catch (exception) // NOLINT(cppcoreguidelines-macro-usage)
+
+#include "doctest_compatibility.h"
+
+#include <nlohmann/json.hpp>
+using json = nlohmann::json;
+
+TEST_CASE("JSON_NO_IO")
+{
+    // everything that does not touch <istream>/<ostream> must keep working:
+    // parsing from and dumping to std::string
+    const json j = json::parse("{\"a\":[1,2,3],\"b\":true}");
+    CHECK(j.dump() == "{\"a\":[1,2,3],\"b\":true}");
+    CHECK(j.at("a").size() == 3);
+    CHECK(j.at("b").get<bool>() == true);
+}
+
+// this test relies on CHECK_THROWS_AS() actually invoking the guarded
+// expression so json_throw_user_call_count gets bumped and can be observed
+// afterwards; doctest's "--no-throw" test filter (which ci_test_noexceptions
+// passes, together with a global -DJSON_NOEXCEPTION added to CMAKE_CXX_FLAGS
+// for every translation unit in that build, this file included) compiles
+// CHECK_THROWS_AS() out to a no-op that never even invokes the given
+// expression -- so json::parse()/at() below would never be called at all and
+// the call-count assertions would fail even though our JSON_THROW_USER
+// override (which always really throws, regardless of JSON_NOEXCEPTION) would
+// have worked fine on its own
+#if !defined(JSON_NOEXCEPTION)
+TEST_CASE("JSON_THROW_USER, JSON_TRY_USER, JSON_CATCH_USER")
+{
+    json_throw_user_call_count = 0;
+
+    // json::parse() is [[nodiscard]] (JSON_HEDLEY_WARN_UNUSED_RESULT); under
+    // GCC in C++11 mode that expands to __attribute__((warn_unused_result)),
+    // which -- unlike a [[nodiscard]] attribute proper -- GCC does not
+    // consider satisfied by doctest's CHECK_THROWS_AS() wrapping the
+    // expression in a (void) cast, so the discarded return value would still
+    // be flagged under -Werror=unused-result; assign it to discard it instead,
+    // matching the established `json _ = json::parse(...)` pattern used
+    // elsewhere in the test suite (see unit-class_parser.cpp)
+    json _; // NOLINT(readability-identifier-naming)
+
+    // a parse error goes through JSON_THROW directly, i.e., through our
+    // JSON_THROW_USER override
+    CHECK_THROWS_AS(_ = json::parse("this is not JSON"), json::parse_error&);
+    CHECK(json_throw_user_call_count > 0);
+
+    // at() on an out-of-range array index internally catches std::out_of_range
+    // (JSON_TRY_USER/JSON_CATCH_USER) and rethrows it as json::out_of_range
+    // (JSON_THROW_USER again), so this exercises all three macros together
+    const int count_before = json_throw_user_call_count;
+    const json arr = json::array({1, 2, 3});
+    CHECK_THROWS_AS(arr.at(10), json::out_of_range&);
+    CHECK(json_throw_user_call_count > count_before);
+}
+#endif

tests/src/unit-regression2.cpp

@@ -18,6 +18,14 @@
 // for some reason including this after the json header leads to linker errors with VS 2017...
 #include <locale>
 
+// skip tests if JSON_DisableEnumSerialization=ON (#4384): std::byte is a
+// scoped enum, so get<std::byte>() (needed below to get<std::vector<std::byte>>()
+// from a plain JSON array, not just from an already-binary value) relies on
+// enum serialization being enabled
+#if defined(JSON_DISABLE_ENUM_SERIALIZATION) && (JSON_DISABLE_ENUM_SERIALIZATION == 1)
+    #define SKIP_TESTS_FOR_ENUM_SERIALIZATION
+#endif
+
 #define JSON_TESTS_PRIVATE
 #include <nlohmann/json.hpp>
 using json = nlohmann::json;
@@ -1136,6 +1144,7 @@ TEST_CASE("regression tests 2")
         CHECK((decoded == json_4804::array()));
     }
 
+#ifndef SKIP_TESTS_FOR_ENUM_SERIALIZATION
     SECTION("discussion #4209 - custom BinaryType direct assignment and round-tripping")
     {
         // Test that assigning a custom BinaryType directly creates a binary value, not an array
@@ -1169,6 +1178,7 @@ TEST_CASE("regression tests 2")
         CHECK(extracted[1] == std::byte{2});
         CHECK(extracted[2] == std::byte{3});
     }
+#endif
 
     SECTION("issue #5046 - implicit conversion of return json to std::optional no longer implicit")
     {

tests/src/unit-std-format.cpp

@@ -52,6 +52,23 @@ TEST_CASE("std::formatter<nlohmann::json>")
         CHECK(std::format("{:2}", j) == j.dump(2));
         CHECK(std::format("{:#2}", j) == j.dump(2));
         CHECK(std::format("{:8}", j) == j.dump(8));
+        // multi-digit widths must accumulate every digit, not just the first
+        CHECK(std::format("{:12}", j) == j.dump(12));
+        CHECK(std::format("{:#12}", j) == j.dump(12));
+        CHECK(std::format("{:10}", j) == j.dump(10));
+    }
+
+    SECTION("bare alignment with no fill character defaults to a space indent character")
+    {
+        const json j = {{"foo", 1}, {"bar", {1, 2, 3}}};
+        // without a preceding fill character, the alignment character itself must not
+        // be mistaken for the indent character -- the default space is kept
+        CHECK(std::format("{:<}", j) == j.dump());
+        CHECK(std::format("{:>}", j) == j.dump());
+        CHECK(std::format("{:^}", j) == j.dump());
+        CHECK(std::format("{:<3}", j) == j.dump(3, ' '));
+        CHECK(std::format("{:>3}", j) == j.dump(3, ' '));
+        CHECK(std::format("{:^3}", j) == j.dump(3, ' '));
     }
 
     SECTION("fill-and-align sets the indent character, like dump(indent, indent_char)")

tests/src/unit-ubjson.cpp

@@ -2149,67 +2149,6 @@ TEST_CASE("UBJSON")
     }
 }
 
-TEST_CASE("UBJSON optimized arrays of a valueless type are bounded")
-{
-    // An element of type 'Z', 'T' or 'F' is encoded by its marker alone, so an
-    // optimized array of one of those has no payload and the declared count is
-    // the only thing deciding how much is allocated. Ten bytes used to produce
-    // billions of values (#2793); every other type costs at least one byte per
-    // element and is bounded by the end of the input.
-    json _;
-
-    SECTION("an excessive count is rejected")
-    {
-        // 'l' is a big-endian int32: 0x7FFFFFFF elements, about 34 GB of value
-        for (const auto marker :
-                {'Z', 'T', 'F'
-                })
-        {
-            const std::vector<uint8_t> input = {'[', '$', static_cast<uint8_t>(marker), '#', 'l', 0x7F, 0xFF, 0xFF, 0xFF};
-            CHECK_THROWS_WITH_AS(_ = json::from_ubjson(input), "[json.exception.out_of_range.408] syntax error while parsing UBJSON size: excessive array size", json::out_of_range&);
-            CHECK(json::from_ubjson(input, true, false).is_discarded());
-        }
-    }
-
-    SECTION("ordinary counts are unaffected")
-    {
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'Z', '#', 'i', 3})) == json({nullptr, nullptr, nullptr}));
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'T', '#', 'i', 2})) == json({true, true}));
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'F', '#', 'i', 2})) == json({false, false}));
-        // 'N' is a no-op rather than a value, and still yields an empty array
-        CHECK(json::from_ubjson(std::vector<uint8_t>({'[', '$', 'N', '#', 'i', 2})) == json::array());
-    }
-
-    SECTION("a type with a payload is unaffected")
-    {
-        // A count past the limit is not rejected for 'U', which costs a byte
-        // per element and is bounded by the end of the input instead. The
-        // count is kept just past the limit rather than made huge, because a
-        // count that also exceeds the array's max_size() is reported as
-        // out_of_range before the input runs out, and max_size() depends on
-        // the width of std::size_t.
-        const std::vector<uint8_t> input = {'[', '$', 'U', '#', 'l', 0x00, 0x10, 0x00, 0x01};
-        CHECK_THROWS_WITH_AS(_ = json::from_ubjson(input), "[json.exception.parse_error.110] parse error at byte 10: syntax error while parsing UBJSON number: unexpected end of input", json::parse_error&);
-        CHECK(json::from_ubjson(input, true, false).is_discarded());
-    }
-
-    SECTION("the writer stays within what the reader accepts")
-    {
-        // below the limit the optimized form is used and is tiny; above it the
-        // writer falls back so that the result can still be read back
-        json const at_limit(1048576, nullptr);
-        const auto v_at_limit = json::to_ubjson(at_limit, true, true);
-        CHECK(v_at_limit.size() == 9);
-        CHECK(v_at_limit.at(1) == '$');
-        CHECK(json::from_ubjson(v_at_limit) == at_limit);
-
-        json const above_limit(1048577, nullptr);
-        const auto v_above_limit = json::to_ubjson(above_limit, true, true);
-        CHECK(v_above_limit.at(1) != '$');
-        CHECK(json::from_ubjson(v_above_limit) == above_limit);
-    }
-}
-
 TEST_CASE("Universal Binary JSON Specification Examples 1")
 {
     SECTION("Null Value")