Bound UBJSON optimized arrays 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 UBJSON array of one of those has no
payload: reading an element consumes no input at all. Its declared count is
therefore the only thing that decides how much is allocated, and nothing
bounded it. "[$Z#l" and a four-byte count is nine bytes of input describing
two billion values; #2793 reports 35 GB and 150 seconds from ten bytes, and
OSS-Fuzz has an out-of-memory and a timeout report for the same shape.

Every other type costs at least one byte per element, so the end of the input
bounds it. 'N' (no-op) is already skipped rather than stored. Objects are not
affected either: each element is preceded by its key, which costs bytes. And
BJData already refuses these markers as an optimized type, so this is a plain
UBJSON matter.

Reject a count above 1,048,576 elements for those three types with
out_of_range.408, the code this reader already uses for a declared size it
will not honour. The check runs before the SAX start event, so no container
is opened and then abandoned.

Rejecting on the read side alone would break the guarantee that anything
to_ubjson() writes can be read back, and would trip the round-trip assertion
in fuzzer-parse_ubjson.cpp. So the writer falls back to the unoptimized
encoding, one byte per element, for arrays of these types above the same
limit. Its decision depends only on the array's size, which is identical for
a value and for anything parsed back from it, so the round trip is stable.

No existing test changes: the largest such count in the test suite is 65,793.
The excessive-size test that already used this shape still passes, now
rejected a little earlier than by the max_size() check it used to reach.

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, ci_test_disableenumserialization, ci_test_skiplibraryversioncheck]
+        target: [ci_cmake_flags, ci_test_diagnostics, ci_test_diagnostic_positions, ci_test_noexceptions, ci_test_noimplicitconversions, ci_test_legacycomparison, ci_test_noglobaludls]
     steps:
       - name: Install build-essential
         run: apt-get update ; apt-get install -y build-essential unzip wget git libssl-dev

cmake/ci.cmake

@@ -242,40 +242,6 @@ 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

@@ -69,6 +69,12 @@ 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

@@ -868,6 +868,12 @@ 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"
 
     ```
@@ -879,6 +885,9 @@ or the encoded length for [CBOR](../features/binary_formats/cbor.md).
     ```
     [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

@@ -58,6 +58,26 @@ 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 //
 ///////////////////
@@ -996,23 +1016,21 @@ class binary_reader
     }
 
     /*!
-    @brief reads a CBOR string
+    @brief reads a definite-length CBOR string
 
-    This function first reads starting bytes to determine the expected
+    Reads everything @ref get_cbor_string accepts except the indefinite-length
-    string length and then copies this number of bytes into a string.
+    form, which that function handles itself. The bytes are appended to @a
-    Additionally, CBOR's strings with indefinite lengths are supported.
+    result, so consecutive chunks of an indefinite-length string can be read
+    into the same string.
 
-    @param[out] result  created string
+    @param[out] result  string the bytes are appended to
 
     @return whether string creation completed
-    */
-    bool get_cbor_string(string_t& result)
-    {
-        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "string")))
-        {
-            return false;
-        }
 
+    @pre @a current is not EOF
+    */
+    bool get_cbor_string_chunk(string_t& result)
+    {
         switch (current)
         {
             // UTF-8 string (0x00..0x17 bytes follow)
@@ -1068,20 +1086,6 @@ 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();
@@ -1092,23 +1096,82 @@ class binary_reader
     }
 
     /*!
-    @brief reads a CBOR byte array
+    @brief reads a CBOR string
 
     This function first reads starting bytes to determine the expected
-    byte array length and then copies this number of bytes into the byte array.
+    string length and then copies this number of bytes into a string.
-    Additionally, CBOR's byte arrays with indefinite lengths are supported.
+    Additionally, CBOR's strings with indefinite lengths are supported.
 
-    @param[out] result  created byte array
+    @param[out] result  created string
 
-    @return whether byte array creation completed
+    @return whether string creation completed
     */
-    bool get_cbor_binary(binary_t& result)
+    bool get_cbor_string(string_t& result)
     {
-        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "binary")))
+        // 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
+
+    @return whether byte array creation completed
+
+    @pre @a current is not EOF
+    */
+    bool get_cbor_binary_chunk(binary_t& result)
+    {
         switch (current)
         {
             // Binary data (0x00..0x17 bytes follow)
@@ -1168,20 +1231,6 @@ 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();
@@ -1191,6 +1240,63 @@ 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
 
@@ -2391,7 +2497,12 @@ class binary_reader
     {
         result.first = npos; // size
         result.second = 0; // type
-        bool is_ndarray = false;
+        // 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;
 
         get_ignore_noop();
 
@@ -2424,13 +2535,11 @@ class binary_reader
             }
 
             const bool is_error = get_ubjson_size_value(result.first, is_ndarray);
-            if (input_format == input_format_t::bjdata && 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 (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;
@@ -2439,7 +2548,7 @@ 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)
+            if (input_format == input_format_t::bjdata && is_ndarray && !inside_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));
@@ -2710,6 +2819,17 @@ 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

@@ -826,7 +826,17 @@ class binary_writer
 
                     std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
 
-                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
+                    // 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()))
                     {
                         prefix_required = false;
                         oa->write_character(to_char_type('$'));

include/nlohmann/json.hpp

@@ -4473,8 +4473,11 @@ 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);
-        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]
+        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]
-        return res ? result : basic_json(value_t::discarded);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in CBOR format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4490,8 +4493,11 @@ 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);
-        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]
+        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]
-        return res ? result : basic_json(value_t::discarded);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     template<typename T>
@@ -4516,8 +4522,11 @@ 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)
-        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]
+        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]
-        return res ? result : basic_json(value_t::discarded);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in MessagePack format
@@ -4531,8 +4540,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in MessagePack format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4547,8 +4559,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     template<typename T>
@@ -4571,8 +4586,11 @@ 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)
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in UBJSON format
@@ -4586,8 +4604,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in UBJSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4602,8 +4623,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     template<typename T>
@@ -4626,8 +4650,11 @@ 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)
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in BJData format
@@ -4641,8 +4668,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in BJData format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4657,8 +4687,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in BSON format
@@ -4672,8 +4705,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in BSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4688,8 +4724,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     template<typename T>
@@ -4712,8 +4751,11 @@ 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)
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
     /// @}
 

single_include/nlohmann/json.hpp

@@ -10745,6 +10745,26 @@ 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 //
 ///////////////////
@@ -11683,23 +11703,21 @@ class binary_reader
     }
 
     /*!
-    @brief reads a CBOR string
+    @brief reads a definite-length CBOR string
 
-    This function first reads starting bytes to determine the expected
+    Reads everything @ref get_cbor_string accepts except the indefinite-length
-    string length and then copies this number of bytes into a string.
+    form, which that function handles itself. The bytes are appended to @a
-    Additionally, CBOR's strings with indefinite lengths are supported.
+    result, so consecutive chunks of an indefinite-length string can be read
+    into the same string.
 
-    @param[out] result  created string
+    @param[out] result  string the bytes are appended to
 
     @return whether string creation completed
-    */
-    bool get_cbor_string(string_t& result)
-    {
-        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "string")))
-        {
-            return false;
-        }
 
+    @pre @a current is not EOF
+    */
+    bool get_cbor_string_chunk(string_t& result)
+    {
         switch (current)
         {
             // UTF-8 string (0x00..0x17 bytes follow)
@@ -11755,20 +11773,6 @@ 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();
@@ -11779,23 +11783,82 @@ class binary_reader
     }
 
     /*!
-    @brief reads a CBOR byte array
+    @brief reads a CBOR string
 
     This function first reads starting bytes to determine the expected
-    byte array length and then copies this number of bytes into the byte array.
+    string length and then copies this number of bytes into a string.
-    Additionally, CBOR's byte arrays with indefinite lengths are supported.
+    Additionally, CBOR's strings with indefinite lengths are supported.
 
-    @param[out] result  created byte array
+    @param[out] result  created string
 
-    @return whether byte array creation completed
+    @return whether string creation completed
     */
-    bool get_cbor_binary(binary_t& result)
+    bool get_cbor_string(string_t& result)
     {
-        if (JSON_HEDLEY_UNLIKELY(!unexpect_eof(input_format_t::cbor, "binary")))
+        // 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
+
+    @return whether byte array creation completed
+
+    @pre @a current is not EOF
+    */
+    bool get_cbor_binary_chunk(binary_t& result)
+    {
         switch (current)
         {
             // Binary data (0x00..0x17 bytes follow)
@@ -11855,20 +11918,6 @@ 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();
@@ -11878,6 +11927,63 @@ 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
 
@@ -13078,7 +13184,12 @@ class binary_reader
     {
         result.first = npos; // size
         result.second = 0; // type
-        bool is_ndarray = false;
+        // 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;
 
         get_ignore_noop();
 
@@ -13111,13 +13222,11 @@ class binary_reader
             }
 
             const bool is_error = get_ubjson_size_value(result.first, is_ndarray);
-            if (input_format == input_format_t::bjdata && 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 (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;
@@ -13126,7 +13235,7 @@ 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)
+            if (input_format == input_format_t::bjdata && is_ndarray && !inside_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));
@@ -13397,6 +13506,17 @@ 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;
@@ -17834,7 +17954,17 @@ class binary_writer
 
                     std::vector<CharType> bjdx = {'[', '{', 'S', 'H', 'T', 'F', 'N', 'Z'}; // excluded markers in bjdata optimized type
 
-                    if (same_prefix && !(use_bjdata && std::find(bjdx.begin(), bjdx.end(), first_prefix) != bjdx.end()))
+                    // 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()))
                     {
                         prefix_required = false;
                         oa->write_character(to_char_type('$'));
@@ -25901,8 +26031,11 @@ 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);
-        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]
+        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]
-        return res ? result : basic_json(value_t::discarded);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in CBOR format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -25918,8 +26051,11 @@ 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);
-        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]
+        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]
-        return res ? result : basic_json(value_t::discarded);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     template<typename T>
@@ -25944,8 +26080,11 @@ 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)
-        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]
+        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]
-        return res ? result : basic_json(value_t::discarded);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in MessagePack format
@@ -25959,8 +26098,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in MessagePack format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -25975,8 +26117,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     template<typename T>
@@ -25999,8 +26144,11 @@ 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)
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in UBJSON format
@@ -26014,8 +26162,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in UBJSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -26030,8 +26181,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     template<typename T>
@@ -26054,8 +26208,11 @@ 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)
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in BJData format
@@ -26069,8 +26226,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in BJData format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -26085,8 +26245,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in BSON format
@@ -26100,8 +26263,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     /// @brief create a JSON value from an input in BSON format (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -26116,8 +26282,11 @@ 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);
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
 
     template<typename T>
@@ -26140,8 +26309,11 @@ 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)
-        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]
+        if (!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);
+        {
+            result = value_t::discarded;
+        }
+        return result;
     }
     /// @}
 

tests/src/skip_library_version_check.cpp

@@ -1,61 +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
-
-// 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

@@ -3288,8 +3288,10 @@ 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 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_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(json::from_bjdata(vR2, true, false).is_discarded());
 
             std::vector<uint8_t> const vR3 = {'[', '#', '[', 'i', '2', 'i', 2, ']'};
@@ -3297,7 +3299,7 @@ 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.110] parse error at byte 14: syntax error while parsing BJData number: unexpected end of input", json::parse_error&);
+            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(json::from_bjdata(vR4, true, false).is_discarded());
 
             std::vector<uint8_t> const vR5 = {'[', '$', 'i', '#', '[', '[', '[', ']', ']', ']'};
@@ -3305,12 +3307,25 @@ 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.112] parse error at byte 14: syntax error while parsing BJData size: ndarray can not be recursive", json::parse_error&);
+            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(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

@@ -42,39 +42,6 @@ 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

@@ -2035,6 +2035,58 @@ 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

@@ -1761,40 +1761,6 @@ 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

@@ -672,102 +672,6 @@ 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-3")
+TEST_CASE("check_for_mem_leak_on_adl_to_json-2")
 {
     try
     {

tests/src/unit-no_io_and_user_exceptions.cpp

@@ -1,91 +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
-
-// 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

@@ -18,14 +18,6 @@
 // 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;
@@ -1144,7 +1136,6 @@ 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
@@ -1178,7 +1169,6 @@ 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

@@ -52,23 +52,6 @@ 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

@@ -2149,6 +2149,67 @@ 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")