* 📝 Fix stale 3.12.x placeholder in operator_ne.md version history
PR #5253 (removing the hand-written operator!= to fix #3868/P2468R2)
merged after the earlier 3.12.x -> 3.13.0 global sweep, so its new
version-history entries were written with the stale placeholder.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 🐛 Fix stale twitter.com link in docset.json
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 📝 Document a duplicate-object-key rejection recipe
RFC 8259 leaves handling of duplicate object keys to the implementation;
this library silently keeps only the last value for a repeated key.
Discussion #5085 asked for an opt-in rejection mode. Decision: don't
change library behavior, but document the existing parser-callback
workaround instead.
Adds a "Recipe: rejecting duplicate object keys" section to
parser_callbacks.md, adapted from a community-contributed workaround.
Fixed an off-by-one bug in the original snippet: object_start reports
the depth of the object's parent, while key events inside that object
report depth+1, so indexing the per-depth key set with the same depth
in both places caused an out-of-bounds access on nested objects.
Verified the published snippet compiles and behaves correctly for flat
duplicates, nested duplicates, sibling objects sharing key names, and
arrays of objects.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Cross-link the duplicate-key recipe with the existing object_t behavior docs
object_t.md and features/types/index.md already document that duplicate
object keys resolve to an unspecified value (RFC 8259 leaves this to the
implementation). The new recipe's intro overstated this as a guaranteed
"last value wins" rule, which isn't true in general -- parsing text keeps
the last value, but constructing from an initializer list keeps the first.
Reworded the recipe to point at object_t's "unspecified" behavior instead
of asserting a specific rule, and added cross-links from both existing
pages to the new recipe.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Turn the duplicate-key recipe into a standalone, compiled example
Replace the inline code fence in the "rejecting duplicate object keys"
recipe with a proper docs/mkdocs/docs/examples/*.cpp + .output pair,
included via --8<-- like every other example on the site. The .output
file was generated by running it through the project's actual example
build (docs/Makefile: single_include, -std=c++11, -DJSON_USE_GLOBAL_UDLS=0)
and cross-checked with `make check_output`, and the source passes the
pinned astyle 3.4.13 formatting unchanged.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix#3868: Remove operator!= to enable P2468R2 rewritten candidate synthesis
Under C++20 P2468R2, a hand-written operator!= suppresses the compiler's
rewritten-candidate synthesis for operator==, preventing heterogeneous
comparisons like `std::string s; json j; s == j;` from compiling.
Fix by removing the hand-written operator!=, allowing the compiler to
synthesize != as !(a==b) in all language modes (C++20 member functions
and pre-C++20 friend functions).
Behavior change: operator!= now returns !(a==b) unconditionally, including
for special values like NaN and discarded. This means:
- NaN != NaN now returns true (matches IEEE-754 semantics)
- discarded != x now returns true for any x (matches !(discarded == x))
This also fixes underlying defects in previously-working code:
- Restores direct == comparison for views vs json (reverts std::ranges::equal
workaround added in PR #3950 to dodge this bug)
- Re-enables std::string == json comparisons (uncomments check in
unit-constructor1.cpp)
Fixes: #3868, #3979
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 🚨 fix warning
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
PR #5248 added a 5th JSON_HAS_RANGES exclusion branch to
macro_scope.hpp (nvcc CUDA 12.0.x/12.1.x, fixed in 12.2, issue #3907)
shortly after #5252 added the "Known compiler/stdlib exclusions"
list to json_has_ranges.md, so the new branch was missing from the
just-added doc section. Bring the list back to parity with the code
(5 exclusion branches, 5 documented).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix stale Clang -Weverything suppression comments; eliminate -Wno-missing-noreturn
cmake/clang_flags.cmake claimed -Wno-unsafe-buffer-usage was needed only
for Doctest and that -Wno-missing-noreturn had "no way to silence...
otherwise" (PR #4871, which never actually attempted a source fix).
Neither held up under investigation (todo 130):
- -Wno-unsafe-buffer-usage is pervasive (208 distinct sites across 19
files measured with clang trunk in silkeh/clang:dev), spanning the
library's own low-level numeric/buffer code (to_chars, serializer,
lexer, binary reader/writer, input adapters, json_pointer) as well as
vendored Doctest itself (96 of the 208 sites). A source-level fix is
not feasible at this scale; the comment now says so instead of
blaming Doctest alone.
- -Wno-missing-noreturn had exactly two real trigger sites, both
genuinely and unconditionally non-returning: a test-only throwing
allocator (tests/src/unit-allocator.cpp) and, previously undiscovered,
wide_string_input_adapter::get_elements<T>() in
include/nlohmann/detail/input/input_adapters.hpp. Verified this isn't
a wider pattern by checking all 160 JSON_THROW call sites in the
library for functions whose entire body is an unconditional throw.
Annotated both ([[noreturn]] in the test file, since JSON_HEDLEY_NO_RETURN
is #undef'd by the time test code runs; JSON_HEDLEY_NO_RETURN in the
library file, its first real use anywhere in the codebase) and
dropped the suppression entirely.
single_include/nlohmann/json.hpp regenerated via `make amalgamate`;
`make check-amalgamation` passes.
Verified in Docker (silkeh/clang:dev, matching the ci_static_analysis_clang
CI job): baseline builds clean, and the full 194-target test suite builds
with zero warnings under the corrected CLANG_CXXFLAGS (-Wno-missing-noreturn
no longer in the list). Also sanity-compiled and ran unit-allocator.cpp and
unit-wstring.cpp on host Apple Clang to confirm behavior is unchanged.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix MSVC C4702 warning caused by JSON_HEDLEY_NO_RETURN on get_elements()
PR #5250 annotated wide_string_input_adapter::get_elements<T>() with
JSON_HEDLEY_NO_RETURN (it unconditionally throws). On MSVC this expands to
__declspec(noreturn), and MSVC correctly determined that the code following
its call in binary_reader.hpp is unreachable for that instantiation, firing
C4702 under /W4 /WX in the msvc, msvc-vs2026, and msvc-arm64 Debug jobs.
Clang doesn't flag this case, so the Docker verification for #5250 (which
only checked Clang -Weverything) didn't catch it.
This is the same warning class already tolerated for Release builds since
PR #5216, where MSVC's optimizer independently found the same dead code
after /Od was removed. Extend that existing /wd4702 suppression to Debug
builds too, instead of reverting the noreturn annotation.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Document std::optional<T> direct-init/copy-init limitation with null
Add regression test pinning current behavior (CHECK_THROWS_AS) in the null
section of unit-conversions.cpp with detailed comment explaining the C++
language-level cause (std::optional's own converting constructor wins
overload resolution over basic_json::operator T()).
Add a warning callout in conversions.md documenting that direct construction/
assignment of std::optional<T> from JSON null throws type_error 302, with a
clear workaround (use get<std::optional<T>>() or get_to() instead, which
correctly produce std::nullopt).
This is a limitation at the language level: there is no SFINAE path to
distinguish "called from inside std::optional's own constructor" from "direct
call", so fixing it would require breaking changes to operator ValueType().
A permanent fix belongs in the 4.0 type-strictness redesign (#3453).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-Authored-By: Claude Code <noreply@anthropic.com>
* Fix issue reference in std::optional test comment
Update the comment in the null section test to reference #5246 instead of
placeholder #XXXX, clarifying where the direct-init/copy-init limitation is tracked.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Use CHECK_THROWS_AS_WITH for std::optional test assertions
Update the regression tests to use CHECK_THROWS_AS_WITH instead of
CHECK_THROWS_AS to verify both the exception type and the error message.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix CI: use CHECK_THROWS_WITH_AS, the macro that actually exists
CHECK_THROWS_AS_WITH is not a doctest macro; the correct one used throughout
this test suite is CHECK_THROWS_WITH_AS(expr, message, exception_type&), with
the message before the type and the type as a reference. The previous commit
didn't catch this because it only compiled the file standalone with default
settings; this TEST_CASE only compiles under
`#if !JSON_USE_IMPLICIT_CONVERSIONS`, which is why ci_test_noimplicitconversions
was the job that failed. Verified by building and running the test in that
exact configuration (JSON_USE_IMPLICIT_CONVERSIONS=0): 14/14 assertions pass.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Run std::optional test under default implicit-conversions build too
TEST_CASE("std::optional") was guarded by #if !JSON_USE_IMPLICIT_CONVERSIONS,
so it only ever compiled in the non-default build with implicit conversions
disabled. This traces back to commit 1d7688aef (fixes#3859), which changed a
previously dead #ifndef JSON_USE_IMPLICIT_CONVERSIONS guard (the macro is
always defined by that point, so it never held) to #if !JSON_USE_IMPLICIT_CONVERSIONS
-- making the test compile for the first time, but only in the disabled-conversions
build. As a result, std::optional support had zero test coverage in the default
configuration almost every user builds with.
Verified the entire test case (all sections: null, string, bool, number, array,
object) compiles and passes identically with JSON_USE_IMPLICIT_CONVERSIONS both
on (default) and off -- nothing in it actually depends on the setting. Removing
the guard closes the coverage gap with no behavior change: 285 assertions pass
with implicit conversions on, 232 with them off (the difference comes from
other, unrelated conditionally-compiled tests in this file).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 🚨 fix warning
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Code <noreply@anthropic.com>
* Test ci_cuda_example against a CUDA version matrix at C++20 (#3907)
The ci_cuda_example job compiled against the json-ci image's CUDA
11.0 toolkit at cuda_std_11, which cannot exercise #3907 (a c++20
parse error in iteration_proxy.hpp's enable_borrowed_range reported
under nvcc). Switch the job to pull official nvidia/cuda devel images
directly and matrix across CUDA 11.8-12.6 at cuda_std_20 so CI can
empirically confirm which versions are actually affected before any
source-level fix is attempted.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix nvcc CUDA 12.0/12.1 C++20 ranges parse error (#3907)
The diagnostic matrix in this PR confirmed the affected range exactly:
nvcc 12.0.1 and 12.1.1 both fail with "expected initializer before
'<' token" on iteration_proxy.hpp's enable_borrowed_range variable
template specialization at -std=c++20; 12.2.2 and newer already build
cleanly. Guard JSON_HAS_RANGES off for that narrow nvcc version range,
matching the existing GCC-11/libstdc++ carve-outs in the same ifdef
chain, and regenerate single_include accordingly.
Broaden the CUDA smoke test to also exercise comparisons
(operator==/operator<=>, gated independently by
JSON_HAS_THREE_WAY_COMPARISON) and range-based iteration, not just
dump()/erase(), so the fix's actual scope is evidenced by CI rather
than assumed from the single reported symptom.
Have tests/cuda_example/CMakeLists.txt pick the newest C++ standard
the detected nvcc version actually supports (20/17/11) instead of
hard-requiring C++20, so older toolkits build at a lower standard
instead of failing CMake configure outright. This is test-project-local
only; the JSON_HAS_RANGES guard is what protects real client code,
since a header can't control what -std= flag it's compiled with.
Right-size the CI matrix from the 8-version diagnostic sweep down to
11.8.0 (C++17 fallback path) / 12.1.1 (permanent #3907 regression
guard) / 12.6.3 (recent coverage), and update the compiler-version
table in the quality assurance docs to match.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix ci_cuda_example CUDA 11.8 build after C++17 fallback (#3907)
The 11.8.0 leg's graceful C++17 fallback (added in the previous commit)
worked correctly, but the broadened smoke test used the <=> operator
unconditionally, which isn't valid syntax pre-C++20 — nvcc rejected it
with "expected an expression" once the CMake logic picked cuda_std_17
for the older toolkit. Gate those two lines behind
JSON_HAS_THREE_WAY_COMPARISON like the library itself does internally.
Sanity-compiled the file as plain C++ at both -std=c++17 (skips the
guarded block) and -std=c++20 (includes it) locally; the actual nvcc
build is verified via CI on PR #5248.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 📝 Fix documentation gaps for 3.13.0 release (todos 138-142)
- Todo 138: Add "Known issues" section to modules.md with compiler-specific troubleshooting (GCC redefinition, MSVC symbol export). Add pointer note to quality_assurance.md.
- Todo 139: Document CBOR/MessagePack half-precision float encoding for NaN/Infinity (0xF9/0xCA with exact byte sequences). Explain pre-3.13.0 double-precision bug mechanism without issue citations.
- Todo 140: Document CBOR negative-integer-overflow rejection (parse_error.112) for magnitudes exceeding int64_t range (already implemented in rev 1).
- Todo 141: Update version history in value.md and operator[].md with behavior-change details, removing issue citations per citation policy (prose is self-contained).
- Todo 142: Global sed replace of 3.12.x → 3.13.0 placeholder across all 20 documentation files.
Revision 2 incorporates feedback to reduce changelog-like issue citations. Only citations that add unique troubleshooting value are retained (#5103 for GCC workaround, #3970 for MSVC symbol export). "Known issues" section follows PR #5252's visual pattern (info admonition with bold-bullet format).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 📝 Document integer type selection, type_name() invalid value, and std::optional get() fix
- number_handling.md: clarify that positive/negative integers select
unsigned/signed storage based on the leading minus sign (todo 143).
- type_name.md: document the new "invalid" return value for corrupted
JSON values (todo 145).
- get.md: note that get<std::optional<T>>() was unreachable in every
configuration prior to 3.13.0 due to an internal macro-guard bug,
unrelated to JSON_USE_IMPLICIT_CONVERSIONS's actual effect (todo 144).
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 📝 Document compiler/stdlib exclusions in macro_scope.hpp
Add "Known compiler/stdlib exclusions" subsections to the public documentation for
JSON_HAS_FILESYSTEM and JSON_HAS_RANGES, listing the exact compiler/stdlib versions
that are silently excluded even when feature-test macros indicate support. Each
exclusion references the originating issue. Also add a pointer note in the compiler
compatibility section linking to these details.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-Authored-By: Claude Code <noreply@anthropic.com>
* 💚 fix build
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Code <noreply@anthropic.com>
When converting objects or strings between different basic_json specializations,
the target's object_t::key_type or string_t must be directly constructible from
the source's corresponding type. If this requirement is not met, the conversion
silently falls back to the array-conversion path, producing incorrect results.
This documents the limitation and provides references to issue #3425, which tracks
this behavior. The comment in unit-alt-string.cpp is clarified to reference the
known limitation with a link to the issue, and suggests the parse() workaround.
Fixes#3425 (documentation; full fix deferred pending type-trait redesign)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Replace snprintf with a branch-free writer for \uXXXX escapes
dump_escaped called std::snprintf(..., "\u%04x", ...) once per escaped
code point in the string serialization hot path. snprintf re-parses
the format string and pulls in locale/printf machinery on every call,
which is far heavier than the fixed 6-/12-byte output warrants. This
is hot for any string containing control characters, and for all
non-ASCII text when ensure_ascii is set.
Replace it with write_u_escape, a small helper that writes the escape
directly into string_buffer via a nibble-to-hex lookup table, mirroring
the existing hand-rolled dump_integer fast path in the same file.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Fix clang-tidy avoid-c-arrays warning in write_u_escape
Use a const char* rather than a char[] lookup table, matching the
existing hex_bytes helper in the same file.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* ♻️ adjust write_u_escape signature
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Implement the scoped agent-readiness subset for json.nlohmann.me:
- Add the mkdocs-llmstxt plugin to generate llms.txt from the nav
(full_output/llms-full.txt deliberately omitted to avoid dumping
500+ API reference pages into one giant file).
- Add a permissive robots.txt with a Sitemap reference.
- Add a build hook (hooks/copy_markdown_source.py) that copies each
page's Markdown source into the built site as a `<path>.md` sibling
of its HTML output, so agents/tools can fetch raw Markdown directly.
sitemap.xml was already emitted by default and needed no change.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
`lexer::get()` copied every scanned character into `token_string` on the
whole successful-parse hot path, yet that buffer is consumed only by
`get_token_string()` when rendering the "last read" fragment of a parse
error. On well-formed input the per-byte copy (plus the `unget()` pop)
is pure overhead that is always discarded.
For seekable input adapters - random-access, single-byte iterators such
as those backing `std::string`, `const char*`, and `std::vector<char>` -
the offending token is now reconstructed on demand from the input when
an error is reported, using a saved start offset, and the eager copy is
skipped. Streaming adapters (file, istream, wide-string, and user-defined
adapters) keep the eager copy; the strategy is chosen at compile time via
`input_adapter_supports_seek`, so adapters without the capability are
unaffected.
Error messages are byte-for-byte identical across all adapters, verified
by a new parity regression test. Microbenchmark (4 MB mixed JSON, parsed
from a std::string): ~149 -> ~160 MB/s, about +8%.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
* Harden CI workflows: validate PR artifact inputs and migrate off deprecated Semgrep action
Address two CI/supply-chain hardening items from the 2026-07-03 security
audit:
- comment_check_amalgamation.yml (todo 117): the privileged `workflow_run`
job consumes an untrusted PR artifact. Validate `author` against a strict
GitHub-username pattern and `number` as a positive integer before use, and
extract the artifact into a dedicated directory (`unzip -o pr.zip -d
./pr_artifact`), reading only the two expected files by fixed path. This
prevents Markdown/mention injection via the attacker-controlled `author`
text and avoids a malicious archive touching the workspace.
- semgrep.yml (todo 118): `returntocorp/semgrep-action` is deprecated (the
org was renamed to `semgrep/*`). Replace it with an explicit `semgrep ci`
invocation via the maintained CLI; the deployment is inferred from
SEMGREP_APP_TOKEN.
Todo 116 (CIFuzz `@master` refs) already carries a comment documenting the
OSS-Fuzz-recommended exception, so no change is needed there.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* Fix Semgrep step: use `semgrep scan` instead of token-gated `semgrep ci`
The CI `Scan` job failed with "Path does not exist: semgrep.sarif" because
`semgrep ci` requires a login token (SEMGREP_APP_TOKEN), which this repo does
not have configured, so it bailed without producing a SARIF file. The former
returntocorp/semgrep-action, given no token, fell back to plain
`semgrep scan --sarif`; match that with `semgrep scan --config auto`, which
needs no token and always produces the SARIF for upload.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Bumps init/analyze/autobuild together (previously split across #5226,
#5227, #5228, which each failed CI due to a version mismatch between
the CodeQL config and the running action). Also adds a dependabot
group so future codeql-action bumps land in a single PR.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
When a PR is not amalgamated/formatted, the astyle version friction (see
the recurring blocker across many PRs) means contributors often struggle
to reproduce the exact fix locally. The check now regenerates the
amalgamation and formatting, captures the difference as a patch, and
uploads it as the `amalgamation-patch` artifact. The failure comment
links to that artifact and tells contributors to run
`git apply amalgamation.patch`, so they no longer need to install the
pinned astyle version themselves.
The pass/fail verdict is unchanged: the same PRs fail as before, and a
correctly amalgamated PR uploads nothing and passes.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* 👷 fix Windows CI
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
---------
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann
