Commit Graph
228 Commits
Author SHA1 Message Date
Niels Lohmann 405b8dcb13 BSON reader: recover from the document size checks made on reading the size
Since #5930, a size below 5, a size that exceeds the enclosing document, and
a size too small for the document's content are reported before the document
is read. When recovering, such a document is now read up to its terminator,
within the enclosing document, and its size is not reported a second time.
BJData now checks an ndarray's type before the object that would hold it is
begun, so that test expects null.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-11-02 13:47:31 +01:00
Niels Lohmann 02d2fa8605 Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-11-02 13:47:30 +01:00
Niels Lohmann b2674a4a2f BSON reader: check array element names in place in strict mode (#5984) 2026-11-01 21:03:35 +01:00
Niels Lohmann f022e3c59c Binary readers and writers: faster UTF-8 checks of strings (#5982)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-11-01 17:23:27 +01:00
Niels Lohmann fb515ddc34 UBJSON/BJData readers: read optimized arrays of numbers in one loop (#5981)
* UBJSON/BJData readers: read optimized arrays of numbers in one loop

An array with a type marker for a fixed-size number ($U, $i, $I, $l, $L,
$d, $D, and BJData's $u, $m, $M), including the data of a BJData ndarray,
gives its elements no markers. When the input is contiguous, read the
elements that are in the input in one loop - load, byte swap for the
format's byte order, emit - instead of one trip through
parse_ubjson_internal and get_ubjson_value per element. Elements the
input ends before, other types, and non-contiguous inputs are read as
before.

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

* UBJSON/BJData tests: assign the parsed value instead of casting it to void

GCC reports -Werror=unused-result for static_cast<void>(json::from_ubjson(...))
and json::from_bjdata(...): a cast to void does not silence warn_unused_result
on GCC. Assign to a json, as the other tests do.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-11-01 17:22:33 +01:00
Niels Lohmann edf8d17601 MessagePack reader: read runs of scalar array elements in one loop (#5980)
* MessagePack reader: read runs of scalar array elements in one loop

As for CBOR: when an array opens and the input is contiguous, read the
integers, floats, booleans, and nils that follow in a tight loop instead
of going through parse_msgpack_internal and parse_msgpack_value for every
element. The loop stops at any other kind of value and when fewer than 9
bytes are left; those values are read by the general path as before.
Non-contiguous inputs are not affected.

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

* MessagePack reader: enter the scalar run only when a scalar follows

As for CBOR: enter_msgpack_array tests the first byte and the remaining length
inline and calls the out-of-line run only for a scalar, so arrays of maps or
strings no longer pay for a call that reads nothing; the run's loop condition
moves to the end (do-while).

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

* MessagePack reader: mark the initial accepted in the scalar run as a false-positive dead store

ci_infer reports DEAD_STORE for 'bool accepted = true;' in the MessagePack
scalar run, as in the CBOR one, because every case assigns accepted before it
is read.

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

* MessagePack tests: assign the parsed value instead of casting it to void

GCC (ci_test_gcc) reports -Werror=unused-result for
static_cast<void>(json::from_msgpack(...)): a cast to void does not silence
warn_unused_result on GCC. Assign to a json, as the other tests in the file do.

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

* MessagePack reader: drop the scalar pre-check before the run

enter_msgpack_array now calls the run directly, and parse_msgpack_scalar_run
tests the remaining count and length at the top of a while loop instead of
relying on msgpack_scalar_follows(); its own switch already leaves on any
value that is not a scalar.

Instructions per repetition, new/old: SAX canada 0.946 (clang) and 0.973
(GCC 13), DOM read canada 0.991 / 0.992; no row more than 0.3 % higher.

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

* MessagePack reader: say why the initial accepted in the scalar run stays

As for CBOR: Infer's DEAD_STORE report is right, not a false positive. The
initializer is kept for clang-tidy's cppcoreguidelines-init-variables.

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

* MessagePack reader: give the scalar run the bulk tag instead of a wrapper

As for CBOR: parse_msgpack_scalar_run takes the bulk-scan tag itself and is
the function kept out of line, so parse_msgpack_array_start goes.

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

* MessagePack reader: start the scalar run's accepted at false

As for CBOR: Infer ignores dead stores of 0, so the suppression goes.

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

* MessagePack reader: let the scalar run find its array itself

As for CBOR: parse_msgpack_scalar_run reads container_stack.back() in its
bulk version, so the caller no longer evaluates it for input that is not
contiguous.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-11-01 17:22:32 +01:00
Niels Lohmann aecbef3949 Binary readers: swap the bytes of floats with a single byteswap (#5976)
* Binary readers: swap the bytes of floats with a single byteswap

byte_swap reversed float and double values byte by byte. GCC does not
merge that loop into one bswap, and C++23's std::byteswap accepts only
integers. Overloads for float and double now copy the bits into a
uint32_t/uint64_t, call detail::byteswap, and copy them back. This
applies to every binary reader that uses get_number.

In the CBOR reader, the single- and double-precision float cases call a
non-inlined helper. Without it, GCC stopped inlining the stream
adapter's get_character() into parse_cbor_internal, which made reading
from a std::istream about 0.5 % slower.

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

* CBOR reader: inline get_cbor_float() and always inline get() instead

The never-inlined get_cbor_float() costs a call for every float read
from input without bulk access: reading canada.json from CBOR through a
FILE* became 5.6 % slower on Apple clang in the benchmark suite. The
helper existed only because GCC 13 stopped inlining the stream adapter's
get_character() into parse_cbor_internal. Always inlining
binary_reader::get() fixes that as well.

callgrind, all binary formats on buffer, std::istringstream and FILE*
input (canada and citm_catalog): GCC 13 0.986-1.003, GCC 16 0.994-1.006,
Clang 23 identical. Apple clang suite: FromBinaryFile/cbor/canada 0.939,
geomean of the 53 binary reader rows 0.998.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-11-01 17:22:32 +01:00
Niels Lohmann 6c3ab966d3 CBOR reader: read runs of scalar array elements in one loop (#5975)
* CBOR reader: read runs of scalar array elements in one loop

When a definite-length CBOR array opens and the input is contiguous, read
the integers, floats, booleans, and nulls that follow in a tight loop
instead of going through parse_cbor_internal's container logic and
parse_cbor_value's dispatch for every element. The loop stops at any other
kind of value and when fewer than 9 bytes are left; those values are read
by the general path exactly as before. Non-contiguous inputs are not
affected (tag dispatch on the bulk-scan capability).

Also pass a member empty string as the number source to number_float
instead of constructing a std::string for every float.

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

* CBOR reader: address review of the scalar-run reader

- parse_cbor_scalar_run: set the size explicitly in every case that
  reads a value, instead of relying on a default that every other case
  overwrites.
- Remove cbor_scalar_follows(): parse_cbor_scalar_run already returns on
  the same conditions, and without the pre-check SAX canada needs another
  8.5 % fewer instructions with GCC 13 (0.915 against the previous
  version), with no row more than 0.5 % worse (Mac and GCC).
- Restore the comment on why parse_cbor_internal copies the container
  frame.

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

* CBOR reader: enter the scalar run only when a scalar follows

An array of containers or strings called the out-of-line run start once per
array only to leave it at once; on nested data (arrays of objects) that call
made reading slower than before the run reader. enter_cbor_array now tests the
first byte and the remaining length inline and calls the run only for a
scalar, so the run's loop condition moves to the end (do-while).

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

* CBOR reader: mark the initial accepted in the scalar run as a false-positive dead store

ci_infer reports DEAD_STORE for 'bool accepted = true;' in
parse_cbor_scalar_run because every case assigns accepted before it is read.

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

* CBOR reader: drop the scalar pre-check before the run

enter_cbor_array calls the run directly again, and parse_cbor_scalar_run
tests the remaining count and length at the top of a while loop; its own
switch already leaves on any value that is not a scalar. The MessagePack
reader is built the same way.

Instructions per repetition, new/old: clang SAX canada 0.983, read canada
0.993; GCC 13 read canada 0.997, the other rows at most 1.004.

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

* CBOR reader: say why the initial accepted in the scalar run stays

Infer's DEAD_STORE report is right, not a false positive: every case that
reaches the read assigns accepted. The initializer is kept for clang-tidy's
cppcoreguidelines-init-variables.

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

* CBOR reader: give the scalar run the bulk tag instead of a wrapper

parse_cbor_scalar_run takes the bulk-scan tag itself and is the function that
is kept out of line, so the one-line parse_cbor_array_start wrapper goes, as
the UBJSON typed run already does.

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

* CBOR reader: start the scalar run's accepted at false

Infer ignores dead stores of 0 (--liveness-ignored-constant defaults to "0"),
and false is 0 to it, so the suppression and its comment go.

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

* CBOR reader: let the scalar run find its array itself

parse_cbor_scalar_run reads container_stack.back() in its bulk version, so
the caller no longer evaluates it for input that is not contiguous.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-11-01 17:22:31 +01:00
Niels Lohmann 76001c6b4c BSON reader: find C-string terminators 8 bytes at a time, skip array element names (#5968)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-11-01 17:20:54 +01:00
Niels Lohmann 60107eda3f Read BJData ND-arrays of float16, restrict ND-array char to 0..127, correct BJData docs (#5931)
* Read ND-arrays of half floats and enforce the char limit in ND-arrays

BJData N-dimensional arrays with element type 'h' (float16) failed to
read with a misleading parse_error.112, because the reader's dtype name
table lacked 'h'. It now maps to "half", the JData name. The writer still
does not pack "half"; such an object is written as a plain object and
reads back equal.

BJData limits 'C' (char) to 0..127 in Draft 2 and Draft 3, and the 1-D
reader enforces this, but ND-arrays with _ArrayType_ "char" wrote values
up to 255 as 'C' elements and read them back without a check. The writer
now only packs values in 0..127 (others fall back to a plain object that
round-trips), and the reader rejects 'C' elements above 127 with
parse_error.113 like the 1-D reader.

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

* docs: correct and complete the BJData documentation

Verify the BJData chapter against the library and the Draft 2/3/4
specifications and fix what did not match:

- bjdata.md: correct the list of unused markers (N, not Z), the ND-array
  example (3x2, not 2x3), the conditions under which an object is packed
  as an ND-array (exactly three keys, row vectors, float-only elements for
  single/double, char 0..127, byte only in Draft 3), the binary table row
  and notes (which flag/draft combinations write [$B), the "$" type
  restriction (Draft 3, Z is excluded too), the H marker in the
  deserialization table, and the claim of a complete deserialization
  mapping. Document the supported drafts, that Draft 4 (SoA containers,
  extension type E) and column-major ND-arrays are rejected, ND-arrays of
  half floats, duplicate object keys, and link the Draft 3 specifications
  instead of master.
- Add an API page for basic_json::bjdata_version_t with an example, and
  link it from the nav, the API index and to_bjdata.
- Update binary_formats/index.md and binary_values.md, which still claimed
  that BJData has no binary type, and fix a wrong byte comment there.
- Document parse_error.115 and the out_of_range.408 cases for from_bjdata,
  the precise other_error.502 condition for to_bjdata, and reword the note
  on truncated unsigned integers in exceptions.md (only ND-array elements
  were truncated before 3.13.0).

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

* Regenerate single_include and apply astyle

Result of make amalgamate (including make pretty) for the preceding changes.

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

* Address review of the BJData documentation

The $ type restriction exists since Draft 2 (Draft 3 added B), $ requires a count, ND char above 127 is rejected on read, and the new API page is listed in alphabetical order in the nav.

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

* docs: format tables, use the Oxford comma

Reformat the tables changed by this PR (BJData serialization and
deserialization mappings, completeness and binary-value tables) so all
rows are aligned, and add the Oxford comma to lists of three or more
items in the added text.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-26 18:25:46 +01:00
Niels Lohmann dc768a7d5d Fix BSON binary subtype 0x02 and check the declared document size earlier (#5930)
* Write and read the inner length of BSON binary subtype 0x02

The BSON specification defines the payload of the "binary (old)" subtype
0x02 as an int32 followed by that many bytes. to_bson wrote the plain
payload instead, so decoders such as pymongo and libbson-based readers
rejected the bytes, and from_bson returned the inner length as part of the
payload (documented as lenient behavior in gh-5333).

The writer now emits the outer length (payload + 4), the subtype, the inner
int32 holding the payload size, and the payload. The reader requires an
outer length of at least 4 and an inner length equal to the outer length
minus 4 (the cases the bson-corpus lists as decode errors), reports parse
error 112 otherwise, and returns only the payload. Both directions change
together so that the round trip keeps working.

The single-reservation fast path for scalar entries declines subtype 0x02
because it has no room for the inner length.

This is a deliberate exception to the opt-in rule for behavior changes:
the previous output was invalid BSON.

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

* Check the declared BSON document size before reading its content

The BSON reader compared a document's declared size with the number of bytes
read only when it reached the terminator. The declared size never bounded
the reads, so a SAX handler saw the keys and values of a document whose size
was too small before parse error 112 was reported.

The container frame now stores the position where the document ends
according to its declared size. open_bson_document rejects a size below 5
(size prefix plus terminator) and an embedded document that does not end
before the terminator of its enclosing document; the element loop rejects an
element whose type byte leaves no room for the name terminator and the
document terminator. The terminator check stays and still catches a declared
size that is too large. No input that was accepted before is rejected now;
documents with a wrong size are reported earlier, with fewer SAX events, a
different byte position and, in three cases, a different message. The error
id (parse_error.112) is unchanged and strict=false still does not skip the
check.

The tests that asserted the old messages and positions are updated, with the
outer sizes of two inputs corrected so that they still exercise the embedded
document. New tests cover the SAX events, a size below 5, and an embedded
document that fits exactly.

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

* Document BSON subtype 0x02, document size checks, and lenient reads

Describe the inner length of binary subtype 0x02 that to_bson now writes and
from_bson checks and removes. Add the document size checks (parse_error.112,
not affected by strict=false) to bson.md and from_bson.md, and extend the
list of lenient reads with the UUID and MD5 payload lengths (not checked),
duplicate keys (last value wins), embedded NUL bytes in strings, and the
ignored trailing bytes with strict=false. State that the members of an object
are written in iteration order.

Correct the statement that element names are never validated on read: they
are checked and sanitized like string values by the error handler. Add the
BSON message to the examples of out_of_range.415 and type_error.321, the
subtype limit of 255 to the binary values page, CBOR to the formats that use
byte_container_with_subtype, and fix a typo in the incomplete mapping box.

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

* Regenerate single_include and apply astyle

Result of make amalgamate (including make pretty) for the preceding changes.

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

* Address review of the BSON documentation

Describe exactly when a too small document size is detected and note that subtype 2 data written by earlier versions is not readable.

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

* docs: use the Oxford comma, drop discarded-value remarks

Add the serial comma in a list added by this PR and remove the BSON
example of type_error.321 (with the type_error.317 remark) so the docs do
not mention discarded values for BSON; restore the original singular
heading of that section. No tables were changed by this PR.

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

* Fix -Weffc++ in the BSON recorder test and a clang-tidy use-auto hit

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

* Fix clang-tidy readability-redundant-member-init in BSON test

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-26 18:25:46 +01:00
Niels Lohmann 0c3570d44a Validate the UBJSON/BJData container type marker for count 0; fix UBJSON docs (#5929)
* Validate the optimized-container type marker for count 0 in UBJSON and BJData

The '$' type marker of an optimized container was only checked when an
element was read, so containers with count 0 accepted any marker:
`[$x#i0`, `{$x#i0` and `[$E#i0` parsed as empty containers although a
non-empty container with the same marker is rejected and the UBJSON
specification requires a legal marker after '$'.

get_ubjson_size_type() now checks the marker right after '$' against the
allowed set (UBJSON: Z N T F i U I l L d D H C S [ {; BJData: B U i u I m
l M L h d D C, with the existing exclusion of T F Z N S H [ {) and reports
parse_error.112 "marker ... is not a permitted optimized array type".

Input that was accepted and is now rejected: an optimized container with
count 0 and an invalid '$' type marker. Valid input is unaffected. Two
existing tests that used an invalid marker incidentally ("[$#" and a
negative-count case) were adapted.

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

* Correct and complete the UBJSON documentation

Fix statements that disagree with the behavior (checked with probes):
- `Z` is null; the unused marker is `N`.
- `$` requires `#`; use_type with use_size=false throws other_error.502 only
  for non-empty arrays, objects and binary values.
- NaN and infinity are written as IEEE 754 float64 and read back unchanged;
  the UBJSON specification encodes infinity as null.
- `H` is documented (semantics, parse_error.115, out_of_range.406); the
  "complete mapping" claim is qualified.
- use_type "same type" means same marker.
- Long Z/T/F arrays lose only the `$` annotation; the `#` count and the
  element markers are kept.
- from_ubjson lists the 112, 113, 115, 406 and 408 causes that occur for
  UBJSON, without the BJData-only ND-array wording.
- Duplicate object keys keep the last value; the `$` type marker is
  validated even for count 0.
- Smaller fixes: float32 row, "map" -> "object", https link, exception 110
  strict case, to_ubjson history of discarded values.

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

* Regenerate single_include and apply astyle

Result of make amalgamate (including make pretty) for the preceding changes.

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

* Address review of the UBJSON documentation

Clarify that empty containers carry no $ annotation of their own and note that a counted N object is not supported.

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

* docs: format tables, use the Oxford comma, drop discarded-value remarks

Reformat the two UBJSON mapping tables that this PR changed (uniform column
widths, padded cells), use the serial comma in lists of three or more in the
added text, and restore the original type_error.321 bullet in to_ubjson.md.

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

* Fix narrowing of the optimized-container count in BJData and UBJSON tests

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-26 18:25:45 +01:00
Niels Lohmann d5da84249f Skip CBOR tags in front of map keys, validate indefinite text chunks, fix CBOR docs (#5927)
* Skip CBOR tags in front of map keys and validate indefinite text chunks

A tag in front of a text string map key was rejected with parse_error.113
even with cbor_tag_handler_t::ignore or store, although tags in front of
values are handled. The tags are now skipped iteratively before the key is
read; the handler error still rejects them.

The chunks of an indefinite-length text string were concatenated before
the single UTF-8 check, so a code point split over two chunks, or an
invalid chunk, was accepted. RFC 8949, Section 3.2.3 requires every chunk
to be valid on its own. With error_handler_t::strict, replace and ignore
each chunk is now checked; keep is unchanged. The chunks are appended with
append(ptr, len), so StringType needs nothing new.

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

* docs: correct and extend the CBOR documentation

Fix the negative-integer rows (they used MessagePack boundaries), the
number_integer range of the 0x1B row, and the half-precision entry in the
list of unused types; correct the NaN history (0xF9 since 3.8.0) and the
tagged-item wording (only the tag directly in front of a byte string is
stored, and only in the 0xD8..0xDB form). Document that to_cbor is not
RFC 8949 deterministic, that duplicate keys are accepted (last wins),
tags in front of keys, per-chunk UTF-8 validation, the exceptions
parse_error.113, out_of_range.406/408 of from_cbor, the pointer and
C array input traps, the partially written output on exceptions, and the
store/ignore results in the binary values example. Drop the claim that
the CBOR reader needs StringType::append(const StringType&) and
BinaryType::insert(pos, first, last).

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

* Regenerate single_include and apply astyle

Result of make amalgamate (including make pretty) for the preceding changes.

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

* Address review of the CBOR changes

Cite RFC 8949 Section 5.3.1 for duplicate keys, describe the out_of_range.408 condition precisely, rewrap a long line, and update the stale get_string comment (per-chunk UTF-8 check). single_include regenerated.

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

* docs: drop discarded-value remarks

Remove the mention that a discarded value cannot be serialized to CBOR
(type_error.321) from the exception-safety and mapping sections. The
integer table and all added prose already follow the table-format and
Oxford-comma rules.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-26 18:25:44 +01:00
Niels Lohmann a6c5d970f3 Merge branch 'develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 06:24:39 +01:00
Niels Lohmann fe5e401870 Consolidate duplicated detail helpers and bodies (#5891) (#5901)
* Add shared detail helpers for the #5891 cleanup

Add detail::is_primitive(value_t), detail::hex4_lower(), detail::utf8_shape(),
detail::input_format_name(), detail::empty_input_message(), the exception ids
116, 319, 320 and 416 to detail::exception_id, and make
detail::is_ascii_copyable() constexpr. Later commits switch the duplicated
code over to them.

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

* 1.4: BSON writers share one write-pass UTF-8 sanitizer (#5891)

write_bson_entry_header and write_bson_string re-derived the error-handler
policy differently. Both now use sanitize_utf8_for_bson_write, which treats
strict like keep (the size pass already validated) and sanitizes replace/ignore
into the bytes the size pass measured. No context plumbing is needed.

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

* 2.1.1: one MessagePack container prefix helper (#5891)

Array and object prefixes differed only in the fix marker and the 16/32-bit
markers; both now delegate to write_msgpack_container_prefix. Output is
byte-identical.

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

* 2.1.2: one iterative walker for CBOR and MessagePack (#5891)

write_cbor_iterative and write_msgpack_iterative (and their *_value_or_push
helpers) were identical but for the head, scalar, and key writers. They are now
one template over a small policy struct, so everything inlines. BON8 keeps its
own walker (open string run, closing marker), noted in a comment.

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

* 2.1.3, 2.1.8: one UBJSON container start helper, shared frame base (#5891)

write_ubjson_start_array/_object are now write_ubjson_start_container<IsArray>,
keeping the array-only begin()+1 scan and excessive_valueless rule.
ubjson_frame derives from binary_container_frame instead of duplicating it.

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

* 2.1.4: write_bytes helper for the byte-string write sites (#5891)

The 13 oa.write_characters(reinterpret_cast<const CharType*>(x.data()), n)
sites now call write_bytes(const void*, size_t); copy_characters sites and the
buffer-based writes are untouched.

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

* 2.1.5: shared object-key writer for CBOR and MessagePack (#5891)

write_cbor_key and write_msgpack_key were the same SFINAE pair apart from the
string/scalar writers; both now delegate to write_object_key<Walk>. UBJSON key
and to_format_length stay as they are.

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

* 2.3.10: writer-side format names from input_format_name (#5891)

The CBOR/MessagePack/UBJSON/BSON/BJData/BON8 literals in throw_on_discarded and
throw_integer_out_of_range calls now come from detail::input_format_name; the
texts are identical, and UBJSON vs BJData still follows use_bjdata.

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

* serializer: constexpr ascii table, hex4_lower, dedupe helpers (#5891)

1.1: build ascii_copyable() at compile time from is_ascii_copyable and
test find_ascii_copyable_run against it for every byte. 1.2/2.5.4: use
detail::hex4_lower in both \uXXXX writers. 2.1.6: factor the repeated
flush/emit blocks in dump_escaped_impl into always-inline helpers.
2.1.7: comment why the escape copy does not use put_buffer.

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

* 1.6: use string_t-aware to_string/concat in meta() (#5891)

Replaces the four std::to_string sites; rendered text unchanged.

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

* 1.7: use detail::is_primitive in json.hpp switches (#5891)

has_no_children, set_parents, max_size and the two diff walkers.

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

* 2.2.1: factor insert()/iterator throw helpers (#5891)

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

* 2.2.2: share swap() overloads via swap_impl (#5891)

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

* 2.2.4: factor primitive reset and range check in erase()/range ctor (#5891)

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

* 2.2.6: share push_back array bodies via push_back_array_impl (#5891)

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

* 2.2.7: route parse/accept/sax_parse through *_impl helpers (#5891)

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

* 2.2.8: share the vector-returning to_* bodies via to_binary_vector (#5891)

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

* 2.2.10: merge destroy_string/destroy_binary into destroy_pointer (#5891)

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

* 2.4.1/1.7: exceptions: share what_impl, flatten diagnostics switch (#5891)

The four create() bodies build their message through one protected
static helper; the diagnostics parent walk handles array/object and
ignores all other types.

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

* 2.4.2/2.4.3/1.7: json_pointer: share slash and escape checks, drop primitive case lists (#5891)

The leading-slash and invalid '~' escape checks are shared helpers; the
reference-token walks test object and array first and treat everything
else as primitive.

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

* 1.7/2.4.9: iter_impl, iteration_proxy: drop primitive case lists, share compare preamble (#5891)

Object and array stay the first branches; everything else is the
primitive case. operator== and operator< share the different-container
check.

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

* 2.4.5/2.4.6: from_json: share get_number_value and reserve_if_possible (#5891)

The three number cases of get_arithmetic_value and the arithmetic
from_json share one helper (boolean stays accepted only by the latter);
the array and object reserve overload pairs become one.

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

* 2.4.8: ordered_map: share erase_impl between the key erase overloads (#5891)

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

* 1.7: json_pointer: flatten walk drops the primitive case list (#5891)

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

* 1.2/1.3/1.5/2.5.1/2.5.2/2.5.5: share helpers in the view code (#5891)

- detail::exception_id at every numeric id; throw_* helpers take it
- hex_byte, hex4_lower, utf8_shape replace local hex/table code
- throw_array_index_out_of_range/_past_end, throw_key_not_found
- has_native_float_format replaces the hand-written IEEE check
No change of messages, ids or output.

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

* 1.5: use utf8_shape in get_bon8_string, add exhaustive UTF-8 validator test (#5891)

get_bon8_string takes the valid range of the second byte from utf8_shape()
(0xF5..0xF7 stay errors, unget behavior unchanged). validate_one_utf8 keeps its
if-chain (hot bulk path); the new test checks decode, validate_one_utf8,
utf8_shape, json::accept and the BON8 reader against each other for every lead
and second byte.

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

* 2.3.1: get_cbor_sized_bytes for the CBOR chunk getters (#5891)

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

* 2.3.2: get_string_with_length for the plain-order string sites (#5891)

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

* 2.3.3, 2.3.4, 2.3.10: unsupported_key_type, empty_input_message, input_format_name in the readers (#5891)

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

* 2.3.7, 2.3.9: read_object_key and leave_container_and_check for CBOR/MessagePack/BON8 (#5891)

UBJSON keys (different getter signature) and its container tail stay as is.

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

* 2.3.5: json_sax_dom_error_state base for the DOM SAX parsers (#5891)

Holds errored, allow_exceptions, parse_error() and is_errored(). The scalar
handlers stay in each class (parse hot path).

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

* 2.3.6: table of control-character messages in the lexer (#5891)

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

* 2.3.8: finish_input helper for the strict-EOF block in the parser (#5891)

sax_parse keeps its if (result) guard and return value. Also adds the
clang-tidy NOLINT for the 2.3.6 message table.

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

* 2.5.7: share parse_array_index between json_pointer and json_view (#5891)

Move json_pointer::parse_array_index() and its status enum to namespace detail
(json_pointer keeps a forwarding member), and let the json_view pointer
resolution use it instead of its own copy of the RFC 6901 index grammar. Both
accepted the same tokens with the same outcome. Also update the comment on
detail::decode(), which listed four of the five UTF-8 validators and now points
to the test that keeps them in sync.

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

* Amalgamate (#5891)

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

* 2.4.5: keep the inlined number cases in from_json(ArithmeticType&) (#5891)

Calling get_number_value() from from_json(ArithmeticType&) made
GetArray<std::array<int, 1000>> 2.4x slower (it changes the inlining of the
std::array conversion), so that overload keeps its own switch, with a comment.
get_arithmetic_value() still uses the shared helper.

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

* 2.5.7: force-inline detail::parse_array_index (#5891)

Moving parse_array_index out of json_pointer stopped clang from inlining it
into the pointer resolution (JsonPointerAt/citm_catalog +17%,
JsonPointerAt/twitter +8%); JSON_HEDLEY_ALWAYS_INLINE restores the baseline.

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

* 1.5: keep get_bon8_string's own UTF-8 ranges (#5891)

Taking the second-byte range from utf8_shape() made BON8 decoding 2-3% slower
(FromBinaryShape/scalars, FromBinaryBuffer, alignment-pinned builds), so the byte
path keeps its hand-written ranges. The exhaustive validator test still checks
that it accepts the same sequences as the other validators.

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

* Amalgamate (#5891)

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

* Fix CI failures: constexpr, NRVO, cppcheck, IWYU (#5891)

- json_sax_dom_error_state::is_errored() cannot be constexpr: the class
  is not a literal type (GCC 4.8, GCC -Wpedantic, Clang 3.5).
- to_binary_vector: destroy the vector writer before returning, as the
  output_vector_sink sets the size of the vector in its destructor.
  Without NRVO (MSVC Debug in C++14 mode), the vector was moved out
  before it was resized.
- parser::sax_parse: return false instead of result after the early exit
  (cppcheck identicalConditionAfterEarlyExit).
- json.hpp: export detail/exceptions.hpp for IWYU, so json_view.hpp can
  name exception_id without including a detail header.

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

* Address review: throw helpers take input_format_t, simpler type checks

- throw_on_discarded() and throw_integer_out_of_range() take an
  input_format_t and call input_format_name() themselves
- has_no_children(), set_parents() and max_size() check array, then
  object, instead of calling is_primitive() first
- parse_impl() chains like accept_impl(); sax_parse_impl() uses if/else
- std::array for the control character messages; negation<> in
  write_object_key(); clarify the is_primitive() comment

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

* json_view: use exception_id in the value() overloads

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

* json_sax: assert the invariant of place_container for the static analyzer

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 06:17:50 +01:00
Niels Lohmann a763c9eb83 Merge branch 'develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-24 07:47:46 +02:00
Niels Lohmann 9c50bdd140 Make the DOM parser cheaper per container and per member (#5882)
* Reserve the parser's nesting stack once

The stack of open arrays and objects was a std::vector<std::uint8_t> that
allocated at the first push_back and then reallocated at 1, 2, 4, 8 bytes,
so a document nested four levels deep made four allocations before it
parsed a value. A document that starts with a container now reserves 32
levels in one allocation; deeper documents grow as before. The loop that
reads the tokens is the code it was, so large documents are not affected
(a stack object with its own storage, and a reserve at every container,
both cost the token loop instructions or cycles).

Fixed cost of parsing a 124-byte object (macOS instructions): accept
-7.6 %, DOM -2.5 %; no change for a single number.

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

* Build arrays of the DOM parser in one exact-size allocation

Reading an array of unknown length appended its elements to a std::vector
one at a time, so a small array reallocated (and moved its elements) at
sizes 1, 2, 4, ... The DOM SAX parser now collects the elements of arrays
whose length is unknown on one stack shared by all open arrays and moves
them into an array of exactly the right size when the closing bracket
arrives. An array that grows past 16 elements switches to appending to its
own vector, so large arrays pay no second copy. Binary formats, which
announce the length, and builds with JSON_DIAGNOSTICS or
JSON_DIAGNOSTIC_POSITIONS (whose values need their final place from the
start) keep storing into the array directly.

The stacks of open containers are reserved on first use instead of growing
from one element.

The binary readers get a DOM parser of their own, json_sax_dom_binary_parser:
it is the plain parser that stores every value directly in its container
(the code the readers used before). Their containers announce their size, so
the bookkeeping of the collecting parser (frame entries, the destination of a
finished container) was pure overhead for them: with the collecting parser
FromBinaryShape nested was 3-12 % and containers up to 5 % more instructions
(GCC) than before. With the plain parser Linux Ir of FromBinaryShape and
FromBinaryBuffer is within 0.8 % of develop (Clang: identical).

canada.json has 56 000 two-element arrays that took three allocations each
and now take two. DOM parse Ir on Linux against develop (GCC / Clang): canada
-7.0 % / -7.7 %, citm -0.8 % / -1.6 %, 124-byte object -5.4 % / -5.5 %;
accept and SAX are untouched.

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

* Reuse one value for the key events of the callback parser

parse() with a callback built a new string value for every key it passed to
the callback (a heap allocation and release per key), and copied the key a
second time into the object. The callback parser now keeps one string value
for key events, which it assigns, and moves the key into the object.

Callback parse, Linux Ir (GCC / Clang): twitter -13.3 % / -11.7 %, citm
-9.5 % / -7.6 %. (Earlier macOS measurement: twitter -19.5 % instructions.)

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

* Remember where the DOM parser stores the next value

The DOM SAX parser looked up the innermost open container for every value:
the end of its frame stack, then the object or array pointer in the frame.
Compilers have to reload all of that after each value is stored, since a
store of a value may alias the frame. The parser now keeps the innermost
container's kind and, for an array that stores directly, the array itself
in members, updated when a container opens or closes.

Flat arrays of numbers are the case that mattered: parsing floats.json
(1 000 000 doubles) into a DOM took 2 % more cycles than before the
previous commit on macOS and now takes 0.4 % fewer than the code before it
(signed_ints.json -0.8 %). Linux Ir is unchanged (canada -6.1 % GCC /
-6.9 % Clang, citm -0.3 % / -0.8 %, twitter +0.2 % / 0.0 %).

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

* Look up the keys of big ordered_json objects in a hash table

ordered_map keeps its elements in a vector and searches it linearly for
every key it adds, so parsing an object with n keys into ordered_json took
O(n^2) key comparisons: 33 billion instructions for one object with 30 000
keys, where json needs 245 million. From 64 keys on, the DOM parser now
keeps a hash table of the keys of the open object (hashes and positions
only; the elements stay in the vector) and finds duplicate keys there. The
result is the same, including the position of a key that occurs twice.
Smaller objects, std::map based objects and key types without std::hash
are untouched.

ordered_json parse, macOS instructions: object with 1 000 keys 64.8 M ->
14.6 M, 10 000 keys 5 104 M -> 38.7 M, 30 000 keys 33 358 M -> 89 M.
Linux Ir of an object with 2 000 keys: 43.0 M -> 1.9 M (GCC), 37.9 M ->
1.8 M (Clang).

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

* Trim the work the DOM parser does per container and per member

Opening and closing an array or object cost the DOM parser more than before
the exact-size array change, which showed on documents of many small
objects (jeopardy.json: +1.4 % Ir with GCC). This takes it back:

- the stack of open containers keeps its first eight entries in the parser
  object instead of in a vector, so it needs no capacity check beyond the
  push itself and no allocation for typical documents;
- a container is created in the place it ends up in, instead of as a
  temporary that is then moved there;
- a new object member, which is null, is constructed over the null instead
  of being swapped with it (only with the default base class of basic_json);
- the key index that big ordered_json objects use is only a part of the
  stack entries of objects that can have one;
- an array that outgrows the stack reserves twice what it has so far, as a
  vector that grew by itself would have.

DOM parse Ir of the series up to here against develop, Linux GCC / Clang:
canada -6.6 % / -7.3 %, citm +1.2 % / +0.2 %, jeopardy +0.4 % / -0.1 %,
124-byte object -6.5 % / -6.2 %. (twitter measures +6.8 % / +6.6 % at this
point in steady state, almost all of it in glibc's malloc/consolidate for the
new allocation sizes; with the last commit of the series it is -0.1 % / 0.0 %.)

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

* Test parsing containers of the sizes where the DOM parser changes storage

The DOM parser collects the elements of an array on a stack (up to 16) and
the members of an ordered_json object (up to 32) before it moves them into
the container, and uses a hash table for keys from 64 members on. Parse
arrays and objects of the sizes around these limits, nested into each other,
with repeated keys, and as random trees that are built next to their text,
and compare json and ordered_json against the value built through the API.

The tests pass on the code from before these changes as well. The random
trees are what finds the mistakes that are easy to make here: while the
collecting change was being written, a collected array that outgrew the
stack at the moment its parent had just reached the limit left its elements
in the parent, and only these tests (142 failed assertions) showed it.

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

* Do not convert floats that cannot overflow in accept()

accept() only has to find out whether a float token is finite: json_sax_acceptor
ignores the value, and the parser rejects only a float that overflows. A
float whose digits fit into 19 digits and whose decimal exponent is at most
max_exponent10 - 19 is below 10^max_exponent10 and cannot overflow, so the
lexer, told by accept() that the value is not needed, skips the conversion
for those. A token that may overflow, with more digits, or in another float
format is converted as before, so 1e309 and its neighbours are rejected as
they were (the new test compares accept() with parse() on tokens around the
limit).

json::accept(): canada.json Ir -8.6 % (GCC) / -10.9 % (Clang), 124-byte
object -3.2 %; cycles on the M1 (release benchmarks, LTO): canada -7.8 %,
floats.json -9.0 %. The check tests the accept() flag first, so the parser
that needs the value pays one load and branch: SaxParse canada +0.35 % Ir
(GCC and Clang), DOM canada +0.4 %.

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

* Collect the members of ordered_json objects on a stack until they are known

An ordered_json object keeps its members in a vector and appends every new
member to it, so reading an object of unknown size reallocated the vector at
1, 2, 4, 8, ... members, and ordered_map copies all keys on every
reallocation. The DOM SAX parser now collects the members of such objects on
one stack shared by all open objects, as it does the elements of arrays, and
moves them into a vector of exactly the right size when the closing brace
arrives. An object that gets past 32 members switches to appending to its
own vector (and, from 64, to the key index of the earlier commit). The
members are the same, in the same order, and a key that occurs twice keeps
the place of its first occurrence. std::map based objects, objects whose
size the input announces (binary formats), and builds with JSON_DIAGNOSTICS
or JSON_DIAGNOSTIC_POSITIONS are untouched.

What only ordered objects need (the collected members, the key indexes) is
a member of the parser only for them, and the code that stores a value tries
the array that takes its elements directly first. An array that outgrows
the stack now reserves 32 elements, the capacity a vector that grew by
itself has at that point; with the larger reserve before, parsing
floats.json (1 000 000 numbers) was 2 % slower on Apple M1 than before this
series.

ordered_json parse, Linux Ir against develop (GCC / Clang): citm -11.6 % /
-11.7 %, twitter -8.4 % / -8.4 %, jeopardy (12 000 objects of 7 keys)
-10.5 % / -8.0 %, canada -3.9 % / -5.2 %, 124-byte object -20.9 % / -16.5 %.
macOS time (M1, earlier base): citm -19 %, twitter -13 %, jeopardy -13 %,
canada -14 %, 124-byte object -26 %. json parse: steady-state twitter -0.1 %
(see the previous commits), citm -1.2 %.

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

* Rename the key index's match callback so Flawfinder doesn't read it as std::equal

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

* Bind the parser test's strings by reference in the range-for loop

GCC and Clang 14 (-Wrange-loop-construct) reported the copy.

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

* Collect container values only in basic_json's own parse functions

A json_sax_dom_parser that a user constructs (as in the sax_no_exception
example) must hold the values read before a parse error, as on develop:
its value is used after the error. The values of containers of unknown
size are now collected on a stack only with the new template parameter
Collect (default false), which json::parse() and the json_view
materialization set; without it, every value is stored in place as it
arrives. A test checks the values kept after an error for json and
ordered_json.

Also fixes the clang-tidy, cpplint and Infer findings: the frame stack
keeps its first frames in a std::array (left uninitialized) and the
others in a std::unique_ptr, auto for create<>(), NOLINT for member
initializers -Weffc++ needs, and an @infer-ignore for the nullptr that
place_container() does not use.

json::parse() and ordered_json::parse() instructions are unchanged
(Apple clang; twitter, citm, canada, jeopardy: -0.03 % to +0.25 %).

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

* Clarify the DOM parser's collection stacks and rename reenter_enclosing_container()

Address review comments: explain why a closed container erases only the top
of the shared stack, set the payload before the type, rename the helper that
makes the enclosing container current again, and declare the parser's state
stack right before reserving it.

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

* Export json_sax_dom_parser from the C++20 module for MSVC

MSVC needs the detail classes that basic_json befriends to be visible in
the module (#3970, as json_sax_dom_callback_parser); with its new
template parameter, json_sax_dom_parser failed in ci_module_cpp20
(C2039, not a member of nlohmann::detail).

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

* Keep the overflow-limit numbers of the parser test in a std::vector

clang-tidy (cppcoreguidelines-avoid-c-arrays) rejected the C array.

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

* Fix the clang-tidy findings of the ordered_json parser tests

The container sizes are a std::array, the expected text uses raw string
literals, the generator's arithmetic is in parentheses, auto for the
result of make<>(), and single characters are appended as characters.
clang-tidy now reports nothing on the lines the branch adds to
unit-ordered_json.cpp and unit-class_parser.cpp (apart from checks CI's
clang-tidy does not have).

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-24 07:41:21 +02:00
Niels Lohmann 6a0cf2ba2f Recover by error kind instead of by error message
The lexer records an error_kind with each error_message, and
recover_token() dispatches on it instead of comparing message prefixes.
add_codepoint() now uses encode_utf8(), and the surrogate pair
formula is shared by scan_string() and recover_low_surrogate().
The stubs for AllowRecovery == false select via negation, which astyle
leaves alone.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-21 09:06:28 +02:00
Niels Lohmann c9fdfc39db Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-15 22:46:35 +02:00
Niels Lohmann 4da73dc5ff Fix compiler warnings on develop from the API performance stack (#5858)
These PRs were merged while their CI runs were cancelled, so the warnings
went unnoticed. All of them fail the -Werror builds:

- json_pointer.hpp (#5836): size_t += int under GCC -Wsign-conversion
- binary_reader.hpp (#5839): char_int_type passed as char under GCC
  -Wconversion
- json.hpp (#5838): @throw without a description under clang
  -Wdocumentation
- string_escape.hpp (#5836): escape_into() was inserted between escape()
  and its documentation, so the @return was attached to a void function
- unit-diagnostics.cpp (#5832): clang -Wnrvo in a lambda without an
  explicit return type
- unit-to_json-rvalue.cpp (#5837): GCC -Wnoexcept (C++20) and clang
  -Wunneeded-member-function on the test type

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-15 22:42:46 +02:00
Niels Lohmann 870bdec01f Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-15 20:56:37 +02:00
Niels Lohmann ed86019a21 Move binary reader error construction out of line (#5839)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-15 20:01:23 +02:00
Niels Lohmann 545477ffa8 Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-11 08:33:14 +02:00
Niels Lohmann 1649d9eda4 Use and extend the detail helpers to remove duplicated code (#5783)
* Use and extend the detail helpers to remove duplicated code

Library:
- binary_reader: format bytes with hex_byte() instead of snprintf
- add throw_type_must_be() for the 20 copies of type_error.302
- binary_reader: add last_byte_error()/unexpected_byte() for the 32
  "parse error at the last read byte" sites (replaces bon8_error)
- json_sax: add check_container_size() for out_of_range.408 and
  diagnostic_positions::set_container_start/_end()
- json_pointer: add throw_no_parent() (405) and throw_unresolved() (404)

Tests:
- unit-class_parser uses the shared utils::SaxCountdown
- move SaxEventLogger (and its ExitAfter* variants) from unit-class_parser
  and unit-deserialization into the new tests/src/test_sax.hpp

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

* Factor out more repeated error paths and test boilerplate

Library:
- add throw_cannot_use_with() for the 34 copies of type_error.304-312
  "cannot use X with Y"
- iter_impl: add throw_cannot_get_value() (invalid_iterator.214)
- parser: add syntax_error() for the 12 parse_error.101 sites
- ordered_map: share the four at() bodies via at_impl()
- json_sax_dom_callback_parser: add pop_container() for end_object()
  and end_array()
- binary_reader: build the two UBJSON/BJData length-type messages with
  concat() and last_byte_error()

Tests:
- move same_value(), the NDEBUG guard, and step 0 (parse without
  exceptions) of the seven fuzzer drivers into tests/src/fuzzer_common.hpp

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

* Name the exception ids and address review comments

Add detail::exception_id, a scoped enum with one named enumerator per
documented exception id, and use it for every id in the library. The
create() functions get an overload for it; the int overloads stay for
user code.

Following the review of #5783: add binary_reader::invalid_byte() and
length_type_error(), basic_json::throw_subscript_wrong_type(), move the
fuzzer includes and the using-declaration into fuzzer_common.hpp, and
rename test_sax.hpp to sax_event_loggers.hpp.

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

* Silence -Wweak-vtables for the SAX event loggers

The loggers moved from anonymous namespaces in the test files into
sax_event_loggers.hpp, so clang now warns that their vtables are
emitted in every translation unit.

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

* Silence MSVC 2015 C4100 in parser::syntax_error for static SAX::parse_error

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

* Inline invalid_byte() into its call sites

The wrapper only fixed the message string of unexpected_byte(), which is
the same kind of per-argument helper that was declined for
throw_type_must_be(). Call unexpected_byte("invalid byte", ...) directly.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-11 08:21:13 +02:00
Niels Lohmann 1d2dea7769 Do not force inlining of the recovery stubs with MSVC
f8ff0942b marked the stubs that stand in for error recovery with
JSON_HEDLEY_ALWAYS_INLINE, which is __forceinline with MSVC. Visual
Studio 2015 and 2017 do not inline them and warn (C4714), which /WX
turns into an error on AppVeyor. The new internal macro
JSON_INTERNAL_ALWAYS_INLINE forces inlining everywhere else (including
clang-cl), and leaves the decision to MSVC. The MinGW objects keep their
smaller section counts, as GCC and clang still inline the stubs.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-09 00:52:35 +02:00
Niels Lohmann f8ff0942b2 Keep the MinGW test objects below the linker's section limit
The MinGW clang job links with a GNU ld that cannot relocate an object
with more than 32767 sections. unit-regression2, unit-regression3 and
unit-msgpack went over it:

- At -O0, the parser and binary reader for parse(), accept() and
  from_*() still emitted the stubs that stand in for recovering, and
  the parser referenced its recovery helpers from code that never runs.
  The stubs are now always inlined, and the parser reaches its helpers
  through the same allow_recovery tag as the stubs, so that this code
  is not even instantiated there. This removes about 300 sections from
  unit-msgpack.
- Every sax_parse call instantiates the parser and binary reader that
  recover from errors. The tests that call it move from
  unit-regression2.cpp (#3989) and unit-regression3.cpp (#5676) into
  unit-sax_parse.cpp, like unit-explicit_instantiation.cpp got a file
  of its own (#5511), and CONTRIBUTING.md points there.

Section counts of the MinGW Debug objects (clang 19, -g0), develop / PR:
unit-msgpack 32281 / 32558, unit-regression2 31272 / 31278,
unit-regression3 32392 / 27462, unit-sax_parse - / 19836.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-08 10:36:16 +02:00
Niels Lohmann dcf7e2222c Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-07 19:24:12 +02:00
Niels Lohmann 069ace74af Round-trip BJData ND-array annotations exactly (single precision, key order) (#5707)
Squashed onto develop from:
- Round-trip BJData ND-array annotations exactly (single precision, key order)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-07 19:17:18 +02:00
Niels Lohmann a2766df787 Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-07 07:42:58 +02:00
Niels LohmannandJoseph.Demarest ff6f3d7d4a Reject nested indefinite-length CBOR string chunks (#5766)
* fix(cbor): reject nested indefinite string chunks

Signed-off-by: Joseph.Demarest <joseph@demarest.dev>
Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address review comments on nested indefinite-length CBOR strings

Rename is_chunk to inside_indefinite, update the stale test section
names, and use lowercase comments like the surrounding code.

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

---------

Signed-off-by: Joseph.Demarest <joseph@demarest.dev>
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Joseph.Demarest <joseph@demarest.dev>
2026-10-07 07:38:52 +02:00
fhgffy 69874e4544 Fix NUL bytes in UBJSON/BJData high-precision numbers (#5760)
* Fix NUL-terminated UBJSON and BJData high-precision payloads

Signed-off-by: fhgffy <102001626+fhgffy@users.noreply.github.com>

* Use English comments for the high-precision NUL fix

Signed-off-by: fhgffy <102001626+fhgffy@users.noreply.github.com>

* Track NUL bytes while reading high-precision payloads

Signed-off-by: fhgffy <102001626+fhgffy@users.noreply.github.com>

* Drop dates from code comments.

Signed-off-by: fhgffy <102001626+fhgffy@users.noreply.github.com>

* Report a NUL in a high-precision number where it is read

Return the parse error from the read loop so the byte offset points at the NUL, and drop the separate check after lexing.

Signed-off-by: fhgffy <102001626+fhgffy@users.noreply.github.com>

* Use fixed text for the high-precision NUL error

2026-10-06: Use the known zero byte directly instead of formatting and concatenating it. Preserve the SAX token, error message, and byte offset.
Signed-off-by: fhgffy <102001626+fhgffy@users.noreply.github.com>

---------

Signed-off-by: fhgffy <102001626+fhgffy@users.noreply.github.com>
2026-10-06 22:30:52 +02:00
Niels Lohmann 632f5369fe Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-06 07:43:24 +02:00
Niels Lohmann 8a142bc436 Fix CI on develop after #5600, #5607, and #5755 (#5764)
* Fix CI on develop after #5600, #5607, and #5755

- binary_reader: cast the result of -1 - number back to number_integer_t,
  because a number_integer_t narrower than int is promoted to int, which
  GCC's -Warith-conversion rejects (ci_test_gcc, ci_test_standards_gcc)
- JSON_DELETE_DEPRECATED_FUNCTIONS: declare the deleted stream operators
  as function templates at namespace scope, because GCC < 5 rejects deleted
  friend functions ("can't initialize friend function") and Clang 7-9 report
  a redefinition when a class template has a deleted friend function
- docs: give the examples of JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS "Example:"
  titles and add the page to the docset (style_check)

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

* Ignore libstdc++'s <format> sign change in the sanitizer job

libstdc++ 14's <format> initializes a size_t parameter with -1 (GCC bug
119429), so every std::format call fails ci_test_clang_sanitizer under
-fsanitize=integer (test-std-format_cpp20). Exclude only the
implicit-integer-sign-change check and only that header via
-fsanitize-ignorelist.

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

* Fix the AppVeyor (MSVC 2015-2019) build

- binary_reader: emit_signed/emit_unsigned pass integers that do not fit
  the number types to emit_float as long double, because MSVC's <cmath>
  has no integer overloads of std::isfinite (C2668 'fpclassify'), from #5607
- scalar comparisons: the friend operators take the JSON type for their
  noexcept from their parameter, because MSVC 2015/2017 take basic_json as
  the class template there (C3203) and MSVC 2019 16.0 does not see member
  types or template parameters, from #5751
- unit-conversions2: skip the !is_nothrow_constructible static_assert for
  std::optional on MSVC 2017, which evaluates the conditional noexcept as
  true (C2607), from #5754

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

* Re-amalgamate

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

* Avoid MSVC 2015's C4800 for enums with underlying type bool

MSVC 2015 warns about any conversion to bool (C4800), even with an
explicit cast, so the enum conversions from #5754 (#5671) failed the
AppVeyor build with /WX. Convert to bool by comparing with zero via the
new detail::bool_aware_static_cast, and keep doctest from printing the
enum in the test.

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

* Skip the #5650 allocator test on MSVC 2015 debug builds

MSVC 2015's debug STL constructs the containers' debug proxies through
the allocator in noexcept constructors, so countdown_allocator's failing
construction crashes test-allocator (SIGSEGV) instead of throwing
std::bad_alloc. Use the guard #5585 uses for the same reason.

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

* Skip deleted-function detection checks on MSVC 2015

MSVC 2015 does not treat selecting a deleted function in decltype as a
substitution failure, so the detection traits in
unit-delete_deprecated_functions (#5755) and the integral-key checks in
unit-element_access2 (#5657) report deleted overloads as callable there.
Calling them still fails to compile. Skip those checks for
_MSC_VER < 1910, and use the stream operators for real in the runtime
section, so MSVC 2015 still compiles them with the macro set.

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

* Split the Visual Studio 2017 AppVeyor jobs in two

The VS 2017 jobs hit AppVeyor's 60-minute limit per job while still
compiling the tests (77 of about 108 test targets after 58 minutes).
They pass /std:c++17 for everything anyway, so build only the C++17
variant of each test (JSON_TestStandards=17), and split the unit test
files across two jobs each with the new JSON_TestShard=<index>/<count>
option, which keeps every <count>-th test file starting at <index>.
The extra variants of single test files are built in shard 0 only.

CMAKE_OPTIONS is no longer quoted in appveyor.yml, so that it can hold
more than one option.

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

* Fix std::terminate when converting std::optional with MSVC 2017

MSVC 2017 evaluates std::is_nothrow_assignable<json&, const T&> as true
even if T's to_json throws, so to_json(json&, const std::optional<T>&)
was noexcept there and the exception from #5642's test called
std::terminate instead of propagating. Make that conversion never
noexcept on MSVC 2017; all other compilers keep the exact condition.
The static_asserts on the condition are skipped for MSVC 2017; the
runtime check that the exception propagates still runs there.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-06 07:22:55 +02:00
Niels Lohmann c2619bf460 Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-04 18:03:20 +02:00
Niels Lohmann 6b4b825af2 Handle numbers that do not fit narrow number types in the binary readers (#5607)
* Handle numbers that do not fit narrow number types in the binary readers

With custom number types narrower than the values in a binary document,
for example basic_json<..., std::int32_t, std::uint32_t, float>, every
binary reader (CBOR, MessagePack, UBJSON, BJData, BSON, BON8) passed the
decoded number to the SAX interface with an implicit conversion: the
integer 5000000000 silently became 705032704, and a finite double such as
1e300 became infinity. The lexer handles the same values in JSON text: an
integer that fits neither integer type is stored as number_float_t, and a
finite number that overflows number_float_t is rejected with
out_of_range.406.

Pass every number read from binary input through three helpers that
apply the lexer's rules:
- emit_signed(): number_integer_t, else number_unsigned_t for a
  non-negative value, else number_float_t
- emit_unsigned(): number_unsigned_t, else number_float_t
- emit_float(): out_of_range.406 if a finite value overflows
  number_float_t; infinity and NaN are passed on

For consistency, a CBOR negative integer below the range of
number_integer_t is now stored as number_float_t, like a too small
integer in JSON text, instead of being rejected with parse_error.112.
With the default number types, this is the only change in behavior.

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

* Fix MSVC and clang 3.5 in the narrow number type test

MSVC types 3000000000 and 5000000000 as unsigned long, so
json(-3000000000) triggered C4146 (unary minus on an unsigned type),
which /WX turns into an error. Use LL literals, as elsewhere in the
tests.

clang 3.5 cannot convert the lambdas in the braced initializer of the
format table to function pointers. Use named functions instead.

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

* Check integer-to-float fallbacks for overflow in the binary readers

emit_signed, emit_unsigned, and the CBOR negative integer fallback now
pass their number_float_t fallback through emit_float, so a value that
overflows number_float_t is rejected with out_of_range.406 like a
floating-point value, instead of silently becoming infinity. This only
matters for a number_float_t that cannot represent 2^64, such as a
half-precision type. The CBOR value -1 - n is computed as long double so
that emit_float sees a finite value.

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

* Use the input_format member instead of passing the format to binary_reader helpers

The helpers (get_number, get_to, get_string, get_binary, get_bytes,
emit_signed, emit_unsigned, emit_float, unexpect_eof, exception_message)
are members of binary_reader, which already stores the format it was
constructed with, so the parameter was redundant.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-04 17:53:29 +02:00
Niels Lohmann 351aeb7440 Merge remote-tracking branch 'origin/develop' into HEAD
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-04 17:19:32 +02:00
Niels Lohmann d8d47be4a5 Fix CI on develop after merging the ready-to-merge PRs (#5754)
* Keep the serializer conversion for objects whose keys cannot be converted

#5591 added a test converting nlohmann::json into a basic_json whose
string type cannot be constructed from std::string. That instantiates
convert_iteratively(), whose members.emplace_back(next.key(), ...) needs
exactly that key conversion, and broke the build of unit-alt-string.
Dispatch on the key's constructibility and leave such conversions to the
serializers, as the levels above the nesting bound already do (#3425).

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

* Fix the remaining CI failures on develop

- unit-wstring: with a 16-bit wchar_t (Windows), a lone surrogate is
  reported as the ill-formed byte 0xFF since #5704; the std::wstring
  expectations still had the previous <U+0000>.
- ci_single_binaries: json_literals.hpp (#5610) and json.hpp include each
  other on purpose, and IWYU, not following the cycle, asks to replace
  json.hpp with json_fwd.hpp. Report its findings without failing the
  build, as already done for json.hpp.

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

* Fix the library warnings and noexcept specifications from the merged PRs

- binary_reader: rename the error_handler constructor parameter, which
  shadowed the member (-Wshadow, -Wshadow-field-in-constructor; #5746)
- basic_json(copy_construct_tag, ...): declare it noexcept when copying
  the base class is (GCC 16 -Wnoexcept; #5690)
- the scalar-on-left legacy comparison operators: noexcept only when
  converting the scalar is, like their member counterparts (#5682, #5751)
- compare_leaves: use std::is_eq/is_lt/is_gt instead of comparing a
  std::partial_ordering with 0 (-Wzero-as-null-pointer-constant; #5686)
- serializer: silence MSVC C4127 for the EnsureAscii template parameter
  (#5741, #5746)
- clang-tidy: return the sanitized reference in binary_writer, take the
  key of ordered_map::find_impl by const reference (#5727), and mark the
  switches over parse_array_index (#5728)
- ordered_map: keep <memory> for std::allocator (IWYU)

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

* Split unit-conversions.cpp so MinGW can link it

clang 18 with the MinGW linker failed to link test-conversions_cpp17
("relocation truncated to fit: IMAGE_REL_AMD64_REL32"). As windows.yml
recommends, keep the objects small by splitting the test file.

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

* Fix the tests added by the merged PRs for all CI configurations

- discard the results of dump() and from_*() in CHECK_THROWS with
  utils::ignore_return_value (GCC -Werror=unused-result)
- give unit-bson's huge_string_t a default constructor (MSVC C2512,
  GCC 5, clang 3.5)
- unit-disabled_exceptions: use the literals namespace when the global
  UDLs are off (ci_test_noglobaludls; #5700)
- unit-binary_utf8_strict: expect the JSON pointer prefix with
  JSON_DIAGNOSTICS (#5741)
- skip the tests that rely on exceptions under JSON_NOEXCEPTION
  (#5678, #5732)
- clang-tidy and clang -Werror: static test data, CAPTURE(...);,
  const-correctness, use-after-move alias, unused conversion operator,
  a missing <iterator> include

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

* Title the macro examples and add JSON_STRICT_BINARY_UTF8 to the docset

The documentation style check requires "Example: ..." titles on pages with several examples (#5741, #5591) and a docset entry for every macro page.

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

* Regenerate BUILD.bazel and nlohmann_json.natvis

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

#5746 added detail/output/error_handler.hpp and #5741 the json_abi_sbu8 ABI tag.

* Install libidn11 for the CMake 3.5.0 binary in ci_cmake_flags

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

#5733 moved ci_cmake_options from ubuntu:focal to ubuntu:24.04, which no longer ships libidn.so.11; the CMake 3.5.0 release binary links against it, so every ci_cmake_flags run has failed since. Install focal's libidn11 package for that matrix entry only.

* Suppress Infer's false STACK_VARIABLE_ADDRESS_ESCAPE in get_impl

get_impl() returns its local by value. A test added by the merged PRs instantiates it with a type Infer misreads, so ci_infer reported the 2021 code for the first time.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-04 17:18:19 +02:00
Niels Lohmann 7b0af0072e Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>

# Conflicts:
#	include/nlohmann/detail/input/binary_reader.hpp
#	include/nlohmann/detail/string_utils.hpp
#	single_include/nlohmann/json.hpp
2026-10-04 12:22:05 +02:00
Niels Lohmann 73e9eae3c1 Add an error_handler parameter for UTF-8 to the binary readers and writers (#5746)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-04 12:13:49 +02:00
Niels Lohmann f56b418c56 Follow each binary format's UTF-8 rule: strict writers (CBOR/UBJSON/BJData/BSON), lenient readers (#5741)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-04 12:13:48 +02:00
Niels Lohmann 1143da4faa Fix CI: keep the binary readers' recovery code out of from_*()
The MinGW job ("clang (20.1.8)", Debug) failed to link test-msgpack_cpp17
with "relocation truncated to fit: IMAGE_REL_AMD64_REL32 against
`.rdata'". Its GNU ld (MinGW 12.2.0) cannot link an object file with
more than 32767 sections. Reproduced with clang 20.1.8 and binutils
2.40: unit-msgpack.cpp's object has 31958 sections on develop and had
33210 with #3989; binutils 2.44 links both.

The readers of from_*() never recover, but unoptimized builds still
emitted the recovery code their dead branches referenced: about 20
helpers per reader instantiation, plus the lexer's recovery functions
through the UBJSON high-precision number repair. Now:

- Errors are reported with report_error() only. The helpers that act on
  the SAX parser's answer (repair_requested(), resync(), value_failed(),
  close_open_containers(), and the repairs of high-precision numbers and
  unsupported BSON elements) have one trivial variant for readers that do
  not recover, so the recovery code is not referenced there.
- Object keys that are not strings and BSON elements whose end is lost
  are marked at the error site and skipped by resync() in the reading
  loops; report_repairable_error(), report_error_repairable_if(),
  report_bson_element_error(), and bon8_error_repairable_if() are gone.
- is_cbor_item_head() is a free function, and the BSON element type is
  formatted as on develop again.

The object now has 32638 sections and links. Behavior is unchanged
(regression tests, binary format suites, and fuzzing), and an optimized
program that only calls from_*() is now 256 bytes smaller than on
develop.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-02 19:48:27 +02:00
Niels Lohmann ab52c98f71 Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>

# Conflicts:
#	docs/mkdocs/docs/api/json_sax/parse_error.md
#	docs/mkdocs/docs/features/parsing/index.md
2026-10-02 11:38:09 +02:00
Niels Lohmann 4d46bce4e1 Fix CI on develop (#5750)
* Fix CI configuration broken by recent merges and tool updates

- gcc_flags.cmake: drop -Wexperimental-fmv-target, which GCC 16 accepts
  only on aarch64; amd64 rejects it, so every GCC job failed while
  checking the compiler.
- ci_get_cmake: add VERBATIM so the checksum pipeline is passed to the
  shell intact (the unescaped `$'` broke the generated Makefile and
  build.ninja, failing ci_cmake_flags and ci_module_cpp20); match the
  SHA-256 entry case-insensitively, as CMake 3.5.0 lists the archive as
  "Linux-x86_64"; and unpack with --strip-components, as that archive's
  top-level directory is spelled "Linux" too.
- ci_single_binaries: compile json.hpp's TU without IWYU's --error, as
  the comment above the gate already intends.
- tests: restore -Wno-deprecated-declarations for all non-MSVC compilers
  (#5737 kept it for GCC only), as several tests call deprecated
  functions on purpose; include thirdparty/fifo_map as SYSTEM.
- .clang-tidy: set misc-use-internal-linkage.AnalyzeTypes to false;
  clang-tidy 22.1 extended the check to classes and enums and flagged
  100 test helper types.

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

* Fix library warnings and a JSON_DIAGNOSTICS parent bug

- binary_reader: pass integers to sax->number_integer() through
  conditional_static_cast<number_integer_t>, making the existing
  narrowing for a narrow number_integer_t explicit (MSVC C4244 and GCC
  -Wconversion/-Warith-conversion with the int16_t test from #5694);
  mark two Infer DEAD_STORE false positives with @infer-ignore.
- to_json: set the parents of an array built from a C++20 range view
  after all elements are in place; a reallocating push_back moved the
  earlier elements and left their parent pointers stale, failing the
  JSON_DIAGNOSTICS invariant assertion.
- json.hpp: suppress MSVC C4127 for the new is_ordered_map check in
  diff(), like the three existing ones; spell out std::formatter::parse's
  return and iterator types for clang-tidy 22.1.
- number_parse: make the Eisel-Lemire digit counter unsigned
  (GCC -Wstrict-overflow).
- string_utils: take encode_utf8's callable by const reference
  (cppcoreguidelines-missing-std-forward) and drop a \u from its doc
  comment (-Wdocumentation-unknown-command).
- ordered_map: include <memory> for std::allocator (cpplint).

Ran make amalgamate.

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

* Fix tests failing in CI on develop

- unit-allocator: skip the #5640 test under MSVC STL iterator debugging,
  where containers allocate a debug proxy in noexcept move constructors
  and a failing allocation terminates; move a decrement out of an if
  condition (bugprone-inc-dec-in-conditions).
- unit-conversions: expect the "(/0)" path with JSON_DIAGNOSTICS;
  compare strict enums via get<>() rather than through the noexcept
  operator==(ScalarType, json), which bugprone-exception-escape flags.
- unit-alt-string: suppress -Wexit-time-destructors for the strict enum
  macro and misc-use-internal-linkage for its enum.
- unit-bjdata: call the static lookup functions through the type and
  pass unsigned char (-Wsign-conversion on amd64).
- Mark Infer false positives with @infer-ignore in unit-diagnostics,
  unit-pointer_access, unit-udt, and unit-conversions.
- Smaller clang-tidy 22.1 findings in unit-class_parser,
  unit-constructor2, unit-custom-base-class, unit-locale-cpp, and
  unit-noexcept.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-02 11:23:55 +02:00
Niels Lohmann 6aec1a085f Report BON8 input that ends after a UTF-8 lead byte as truncated (#5677)
A lead byte (0xC2..0xF7) inside a string begins either another character
(if a continuation byte follows) or an integer (otherwise). When the input
ended right after the lead byte, the reader took the missing byte as "not
a continuation byte", ended the string before the lead byte, and treated
the lead byte as the start of the next value. With strict=false, a message
cut off there was therefore read as a shorter value: the 11 bytes of
"😀😀é" cut after 9 bytes gave "😀😀", and ["aé"] cut after 3 of its 5
bytes gave ["a"]. With strict=true, the input was rejected with a
misleading message ("expected end of input"), or, for a key, with
parse_error.112 instead of 110.

Either reading of the lead byte leaves the message incomplete: a string at
the end of a message must be terminated by 0xFF, so the lead byte cannot
belong to a following message. Report parse_error.110 (unexpected end of
input) for strings and keys, as the comment on get_bon8_string() already
requires and as the reference decoder (HikoGUI) does.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-02 07:47:50 +02:00
Niels Lohmann e5a89d671f Fix lint debt: enum-macro NOLINTs, doctest as SYSTEM, no-op analyzer (#5737)
* Drop stale LCOV_EXCL_LINE from the json_pointer out_of_range.410 throw

The comment said the size_type overflow check in array_index() is only
triggered on special platforms like 32-bit, and the throw was excluded
from coverage. On 64-bit platforms the check is true for SIZE_MAX
itself, and unit-json_pointer.cpp has asserted that case four times
since #5395, so the line is executed in the coverage job. Reword the
comment and remove the exclusion marker so the coverage report notices
if the tests stop reaching it.

Part of #5725

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

* Name all three C-array check aliases in the enum-macro NOLINTs

NLOHMANN_JSON_SERIALIZE_ENUM(_STRICT) suppressed the c-array warning
under modernize-avoid-c-arrays only, but clang-tidy emits the same
diagnostic under the aliases cppcoreguidelines-avoid-c-arrays and
hicpp-avoid-c-arrays too. Any user running those checks got a false
positive at every macro expansion, and our own tests needed a local
NOLINT at each call site to work around it.

Name all three aliases in the four macro comments instead, and drop
the now-redundant c-array names from the five test call-site NOLINTs.
Comment-only change; behavior, the public API, and the ABI do not
change. Ran make amalgamate.

Part of #5725

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

* Include doctest as a SYSTEM directory instead of disabling warnings for all tests

test_main added -Wno-deprecated and -Wno-float-equal as PUBLIC compile
options for every non-MSVC compiler, so they were applied to every
translation unit, library headers included, and silenced the CI
warnings meant to check the library's own -Wfloat-equal pragmas. The
only code that actually needed the suppression was the vendored
doctest.h, which was included as a normal (non-SYSTEM) directory.

Include thirdparty/doctest as SYSTEM for test_main, matching what
tests/abi/CMakeLists.txt already does, and drop the two suppressions
from both targets. Verified locally that unit-comparison,
unit-conversions and unit-constructor1 compile clean with
-Werror -Weverything and doctest as -isystem, and that CMake still
configures with JSON_BuildTests=ON.

Part of #5725

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

* Remove the no-op ci_clang_analyze target

ci_clang_analyze configured the build with the real compiler and only
then wrapped ninja with scan-build. scan-build intercepts compiles by
overriding CC/CXX, but build.ninja already had the compiler path baked
in from the configure step, so every run bypassed the analyzer: CI
logs show "No bugs found" after a normal build, never an analysis.
The job also used Debian's frozen clang-tools-14 rather than the
image's own clang, and CLANG_ANALYZER_CHECKS still named three
valist.* checkers that current clang merged into security.VAList.

ci_clang_tidy already runs every clang-analyzer-* check (via
.clang-tidy's "Checks: '*'") with warnings as errors, so nothing is
lost by removing the dead job. Delete ci_clang_analyze,
CLANG_ANALYZER_CHECKS and the SCAN_BUILD_TOOL lookup from
cmake/ci.cmake, drop it from the ubuntu.yml ci_static_analysis_clang
matrix, and drop the now-unused clang-tools apt package (iwyu stays
for ci_single_binaries). Reword quality_assurance.md and
assurance_case.md, which described the dead job as a working control,
to say the Clang Static Analyzer checks run through clang-tidy.

Verified that `cmake -DJSON_CI=ON` still configures cleanly and that
ci_clang_analyze no longer appears in the generated build or in any
CMake/workflow file.

Part of #5725

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

* Re-enable portability-template-virtual-member-function; remove redundant forwards

.clang-tidy disabled three checks "to get the CI going" (#4489,
2024-11-13): portability-template-virtual-member-function,
bugprone-use-after-move and its alias hicpp-invalid-access-moved.

portability-template-virtual-member-function only flagged
output_stream_adapter::write_character/write_characters; annotate
both with NOLINT and re-enable the check.

bugprone-use-after-move flagged several double forwards that have no
effect at runtime:
- from_json.hpp calls std::forward<BasicJsonType>(j).at(Idx) inside
  pack expansions; at() has no ref-qualified overloads and always
  returns an lvalue reference, so the forward is a no-op. Replace with
  plain j.at(Idx) in all four places.
- the move constructor forwards the whole object to its base class
  and then reads other's members. That is item 9 of #5724 (together
  with its cppcheck suppressions) and is left to that change.
- input_adapters.hpp forwards the container twice on purpose, so the
  begin/end iterator types match adapter_type; annotate with NOLINT
  and a comment instead of changing behavior.

The check still flags the move constructor (see above) and two sites
in at(KeyType&&) (both overloads, json.hpp, in the throw's
string_t(std::forward<KeyType>(key)) after
find(std::forward<KeyType>(key))). Open PR #5689 rewrites that hunk,
so bugprone-use-after-move (and hicpp-invalid-access-moved)
stay disabled for now, with a comment explaining why; re-enable them
once #5689 and the #5724 move-constructor change have landed.

Also resolve the portability-avoid-pragma-once TODO: single_include
never has #pragma once (amalgamate.py strips it) and every supported
compiler accepts it in include/, so keep it disabled with an
explanatory comment instead of a TODO. Fix the stale "json.hpp,
around line 1265" comment in unit-class_parser.cpp, which now points
at the move constructor's actual line.

Behavior, the public API and the ABI do not change. Verified with
clang-tidy 22.1.8 that portability-template-virtual-member-function
now reports nothing, that bugprone-use-after-move/
hicpp-invalid-access-moved report only the known at(KeyType&&) and
move-constructor sites, and that unit-custom-base-class, unit-constructor1,
unit-conversions, unit-element_access2, unit-class_parser and
unit-diagnostic-positions (JSON_DIAGNOSTIC_POSITIONS=1) compile
under ASan/UBSan and pass with the same assertion counts as before.
Ran make amalgamate.

Part of #5725

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

* Fix stale and malformed NOLINT comments

json_sax.hpp named "-warnings-as-errors" in the NOLINT list on the two
JSON_ASSERT(false) lines; that is the suffix clang-tidy appends to a
diagnostic tag under WarningsAsErrors, not a check name, and every
other JSON_ASSERT(false) omits it.

unit-capacity.cpp carried 30 "// NOLINT(misc-const-correctness)"
comments on "json j = ...;" declarations that are all used with
non-const members afterwards, so the check has nothing to report
there.

unit-constructor2.cpp used a blanket "// NOLINT: access after move is
OK here" on a use-after-move that hides every check on the line;
naming bugprone-use-after-move and hicpp-invalid-access-moved keeps
the intent once those checks are re-enabled (#5724).

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

#5725 item 10

* Remove stale .clang-tidy entries

-google-runtime-references disabled a check that neither clang-tidy
22.1.8 nor 23.1.2 lists under --list-checks -checks='*'; it was
removed upstream. The commented-out HeaderFilterRegex line has been
unused since the active HeaderFilterRegex was introduced in #2561
(2021).

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

#5725 item 11

* Remove the GCC C++20 -Wignored-attributes pragma in json.hpp

The pragma (added in #5164) claimed to work around the C++ modules
redefinition errors of #5103, but #5103 is about hard errors (e.g.
"redefinition of std::__is_constant_evaluated()", conflicting
std::integral_constant) that ignoring a warning cannot suppress; they
are traced to GCC PR 124430 and reproduce with <map> or <string>
instead of json.hpp too. A GCC 16.2 -std=gnu++20 -fmodules build
following #5103's repro steps still fails with the pragma in place,
and a build of all test TUs with GCC_CXXFLAGS (which enable
-Wignored-attributes) and the pragma removed produces no such
warning. The block only hid a warning class from GCC C++20 users
while suggesting #5103 was handled.

Overlaps #5610, whose hunks touch the closing half of this pragma to
insert the json_literals.hpp include.

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

#5725 item 9

* Fix stale doxygen comments hidden by the -Wdocumentation pragma

macro_scope.hpp ignores -Wdocumentation and -Wdocumentation-unknown-command
for the whole library, which also hides genuine documentation mistakes:

- detail::unescape() documented "@return unescaped string" but returns
  void and unescapes its argument in place; reworded to
  "@param[in,out] s string to unescape in place" and dropped the
  bogus @return.
- basic_json::get()'s copy-conversion overload wrote "converted to
  @tparam ValueType" inside @return, which Doxygen and Clang parse as
  a second, malformed @tparam; changed to "@a ValueType", matching the
  two other get() overloads a few lines above that already use it.

This narrows the gap the -Wdocumentation pragma needs to cover; fully
replacing the Doxygen-only commands it also hides (item 2c) is left
for after #5267.

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

#5725 item 2

* Fix -Wextra-semi-stmt at its actual source, not assert()

clang_flags.cmake blamed the global -Wno-extra-semi-stmt on assert(),
but assert() expands to an expression under glibc and libc++ and does
not trigger this warning. unit-assert_macro.cpp overrides JSON_ASSERT
with "{if (!(x)) ++assert_counter; }", a bare block followed by a
semicolon at every JSON_ASSERT(...) call site in the library; that
was the actual source of 151 of the 208 -Wextra-semi-stmt sites found
in a Clang 22 -Weverything sweep of the test suite with the flag
removed. Switched to the standard do/while(false) macro idiom, which
does not expand to a statement-plus-semicolon, and corrected the
comment to name the remaining source instead: vendored Doctest's
CAPTURE(x) shim, which already ends in a semicolon.

Verified with clang++ -Wextra-semi-stmt (plus the file's other CI
ignores) that unit-assert_macro.cpp now compiles without any
-Wextra-semi-stmt diagnostic.

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

#5725 item 8 (step 1 of 2; step 2 covers the CAPTURE() call sites)

* Drop the redundant semicolon from CAPTURE() call sites; remove -Wno-extra-semi-stmt

doctest_compatibility.h defines CAPTURE(x) as DOCTEST_CAPTURE(x); (with
a trailing semicolon baked into the macro), specifically so call sites
do not need to add one themselves; most of the ~267 call sites already
follow that convention. The remaining 64 call sites across 20 files
wrote "CAPTURE(x);" anyway, turning into a statement plus an empty
statement and triggering -Wextra-semi-stmt. Dropped the redundant
semicolon at each of those sites.

With item 6 having already made vendored Doctest a SYSTEM include, and
this the last known source of -Wextra-semi-stmt findings, removed the
flag from clang_flags.cmake entirely.

Verified with clang++ -Wextra-semi-stmt (plus the file's other CI
ignores) that all 20 touched files, plus a file with no CAPTURE() use
(unit-json_pointer.cpp), compile without any -Wextra-semi-stmt
diagnostic.

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

#5725 item 8 (step 2 of 2)

* Switch ci_static_analysis_clang off the frozen LLVM 22 dev image

ubuntu.yml pinned the clang-tidy/clang-tidy-sanitizer/single-binaries
job to silkeh/clang:dev, a tag last pushed 2026-02-18 that reports
"clang version 22.0.0 (...+20251015...)", a pre-release snapshot from
before the LLVM 22 release; the maintainer now updates dev-unstable,
22, and latest instead. Switched to silkeh/clang:22, matching the
other clang jobs on :latest.

Verified with clang-tidy 22.1.8 (the image's actual version) against
this repository's .clang-tidy and library headers what the release
image newly reports compared to :dev:

- readability-redundant-typename fires at ~250 sites across the
  _cpp20-relevant conversion/to_chars headers; the library targets
  C++11 and keeps the typenames, so the check is disabled in
  .clang-tidy, matching how the file already handles checks that
  don't fit a C++11 codebase.
- misc-anonymous-namespace-in-header fires on the two anonymous
  namespaces in from_json.hpp and to_json.hpp; added the alias to
  their existing NOLINT (cert-dcl59-cpp, fuchsia-header-anon-namespaces,
  google-build-namespaces).
- bugprone-std-namespace-modification fires on every addition to
  namespace std: the std::hash, std::formatter and std::swap
  overloads in json.hpp, and the std::tuple_size/std::tuple_element
  specializations in iteration_proxy.hpp (this last file is not named
  in #5725's item 5, found by actually running clang-tidy 22.1.8
  against the current tree). All six are legal, deliberate additions
  to namespace std (explicit/partial specializations of std types, or
  the pre-C++20 std::swap overload); annotated each with the check
  name next to its existing cert-dcl58-cpp NOLINT.
- modernize-avoid-c-style-cast reported nothing new.

Also added clang++-22/21, clang-tidy-22/21, g++-16 and gcov-16 to the
find_program search lists in ci.cmake so a local "maximal warnings"
configure prefers the current toolchain version over an older one on
PATH.

#5725 item 5

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

* Regenerate cmake/gcc_flags.cmake for GCC 16.2.0

GCC_CXXFLAGS was generated for GCC 15.1.0, but ci_test_gcc and
ci_test_gcc_cxx{11..26} now run in gcc:latest, currently GCC 16.2.0,
so the "maximal warnings" job was missing warnings introduced since
15.1.0 while carrying entries GCC 16 treats as duplicates or no-ops.

Regenerated with https://github.com/nlohmann/gcc_flags (patched
locally to not crash on an option whose "-x c++ <opt> -" probe fails
before it reads stdin, e.g. -Wabi=; the tool otherwise raises
BrokenPipeError instead of recording the option as an error) run
against g++ 16.2.0 in the official gcc:16 Docker image, keeping the
documented -Wno-* exclusions and the same alphabetical placement
scheme as before.

Also added three GCC 16 warnings the generator cannot discover on its
own because it only probes value ranges/lists it finds in the -Q
option name itself, not in the enum choices --help=warnings documents
separately:

- -Wbidi-chars=any, -Wleading-whitespace=spaces: manually verified
  these compile cleanly with g++ 16.2.0.
- -Wstrict-flex-arrays: deliberately NOT added, unlike the other two.
  Without -fstrict-flex-arrays (which the library does not enable, as
  it would change codegen for flexible array members), GCC prints
  "'-Wstrict-flex-arrays' is ignored when '-fstrict-flex-arrays' is
  not present" on every translation unit, and under our -Werror that
  note itself aborts the build. This differs from the harmless
  no-op warnings already kept in the file (-Whsa, -Wsynth,
  -Wunreachable-code, -Wunsafe-loop-optimizations), which emit
  nothing; #5725 item 7 named -Wstrict-flex-arrays as one of the
  flags GCC 16 adds, but did not anticipate this failure mode.

Verified: compiled the library header and a representative set of
test translation units (including ones touched by items 1, 3, 8, 9,
10 of this issue) with the regenerated GCC_CXXFLAGS plus -Werror
under g++ 16.2.0 at -std=c++11 through -std=c++26, with zero warnings;
ran the full local test suite (129/129 passing, unrelated to this
compiler) as a regression check. CI must still confirm the actual
ci_test_gcc / ci_test_standards_gcc targets end to end, since this was
verified with direct g++ invocations rather than through the CMake/
CXXFLAGS environment-variable plumbing in ci.cmake.

#5725 item 7

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

* Avoid std::basic_string<CharType> for non-character output_adapter CharType

output_adapter<CharType, StringType> defaulted StringType to
std::basic_string<CharType>, and (with JSON_NO_IO undefined) always
declared a std::basic_ostream<CharType>&-taking constructor. For
CharType with no non-deprecated std::char_traits specialization (only
std::uint8_t is ever used this way, by the binary writers), simply
naming either type - as an unused default template argument, or as an
unused, never-called constructor's parameter type - instantiates
std::char_traits<CharType> merely to name it, which some standard
libraries mark deprecated: with the library-wide -Wdocumentation
pragma (item 2's other half, left for a later commit) temporarily
removed, an Apple clang 21 / libc++ TU calling json::to_cbor(j, vec)
with std::vector<std::uint8_t>& got one -Wdeprecated-declarations
warning per binary writer at the old output_adapters.hpp:193.

Replaced the eager std::basic_string<CharType> / std::basic_ostream
<CharType> defaults with a bool-tagged partial specialization (not
std::conditional, which requires naming both branches' types up
front regardless of which is selected, reproducing the same warning)
that only ever names std::basic_string<CharType> / std::basic_ostream
<CharType> when CharType is actually one of char, wchar_t, char16_t,
char32_t, or (with __cpp_lib_char8_t) char8_t. For any other
CharType, output_adapter's StringType and ostream-constructor
parameter fall back to two distinct empty placeholder types, kept
distinct so the two constructor overloads do not collide into a
single redeclaration.

Public API / behavior: passing a std::basic_string<std::uint8_t>& or
std::basic_ostream<std::uint8_t>& directly to a binary writer's
output_adapter now fails to compile instead of compiling with a
deprecation warning; this was neither documented nor tested. All
documented uses (std::vector<CharType>, std::basic_ostream<CharType>
and StringType for character CharType) are unaffected.

Verified with Apple clang 21 / libc++, with the two -Wdocumentation*
"ignored" pragma lines in macro_scope.hpp temporarily removed and
-std=c++11/c++20 plus the project's -Weverything flag set: calling
to_cbor/to_msgpack/to_ubjson/to_bjdata/to_bson/to_bon8 on a
std::vector<std::uint8_t> now produces no char_traits<unsigned char>
(or any other) deprecation warning, while the char-based string- and
ostream-adapter paths, and a to_cbor/from_cbor round trip, still
compile and run correctly; also verified with GCC 16.2.0. Ran the
full local test suite, including the binary-format unit tests
(unit-cbor, unit-msgpack, unit-ubjson, unit-bjdata, unit-bson,
unit-bon8, unit-binary_writer_sinks, unit-binary_formats,
unit-custom-binary-type): 129/129 passing.

#5725 item 2 (step a)

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

* Remove the library-wide -Wdocumentation pragma; fix what it hid

macro_scope.hpp / macro_unscope.hpp pushed and popped a Clang
diagnostic region over the entire library that ignored -Wdocumentation
and -Wdocumentation-unknown-command. Removed both pragmas and fixed
every finding a full -Wdocumentation (which implies
-Wdocumentation-unknown-command and -Wdocumentation-deprecated-sync)
build reports, so the library now compiles clean under Clang's
documentation checks without a blanket suppression. Overlaps #5267,
which is still open and edits a nearby doc block (json.hpp's
get()/get_impl() @return, already fixed in the item 2 step (b) commit
of this branch); this commit does not touch that block again.

Unknown Doxygen alias commands (Doxyfile removed in #3071, so these
were never rendered by anything) rewritten as plain prose, keeping the
same information:
- @requirement REQ-JSON-01 / REQ-JSON-02 (iter_impl.hpp,
  json_reverse_iterator.hpp): now "This class satisfies the following
  concept requirements (REQ-JSON-0N):".
- @liveexample{prose,example-id} (three sites in json.hpp): kept the
  prose, dropped the command wrapper and the trailing example-id
  (docs/mkdocs/docs/examples/*.cpp still exist and are used directly
  by the rendered docs, not through this in-header alias) and
  unescaped the "\," commas that were only needed for the old alias's
  comma-separated argument syntax.
- @complexity X (json.hpp x4, json_pointer.hpp x2, serializer.hpp x1):
  now "Complexity: X".

Backslash sequences Clang's comment lexer tried to parse as commands,
escaped to render as literal backslashes:
- lexer.hpp get_codepoint(): two `\u` occurrences.
- binary_reader.hpp get_bson_cstr() / get_bson_cstr_bulk(): two
  `\x00` occurrences.
- serializer.hpp: three `\uXXXX` occurrences (constructor @param,
  append_codepoint_to_string_buffer() @brief, and the ensure_ascii
  member comment).

One finding remained after all of the above: Clang reports
"declaration is marked with '@deprecated' command but does not have a
deprecation attribute" on the deprecated sax_parse(span_input_adapter&&, ...)
overload, even though JSON_HEDLEY_DEPRECATED_FOR does expand to
__attribute__((deprecated(...))) for Clang. Several isolated
reproductions of this exact declaration shape - doc comment,
template<>, two stacked __attribute__ macros, an overload set sharing
the name - did not reproduce the warning, so this looks like a
Clang comment/declaration-association quirk specific to this overload
inside the much larger basic_json class template, not an actual
documentation defect. Rather than keep the pragma library-wide for one
Clang false positive, added a tightly scoped
-Wdocumentation-deprecated-sync push/pop around just that overload.

Verified with Apple clang 21 and the project's actual -Weverything
flag set (cmake/clang_flags.cmake) on the full header at -std=c++11
and -std=c++20: zero -Wdocumentation* diagnostics. Also compiled
clean with GCC 16.2.0 (the pragmas are already __clang__-gated, so
this only confirms no unrelated breakage). Ran make check-amalgamation
and the full local test suite: 129/129 passing.

#5725 item 2 (step c)

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

* Take the JSON value by const reference in the array and tuple from_json paths

Review feedback on #5737 (gregmarr): once the no-op std::forward calls
are gone, the forwarding references have no purpose. from_json_fn
passes the value as const BasicJsonType&, so these functions were only
ever instantiated with a const lvalue anyway.

The std::array, std::pair and std::tuple overloads of from_json and
their helpers now take const BasicJsonType& and pass j on unchanged.
Because the deduced BasicJsonType is now the plain type, tuple_type and
the static_assert name const BasicJsonType& explicitly, so the
reference checks are unchanged: get<std::tuple<const std::string&>>()
still works, and get<std::tuple<std::string&>>() still fails the same
static_assert. from_json_tuple_get_impl keeps its forwarding reference,
since tuple_type calls it through std::declval.

Behavior, the public API and the ABI do not change. unit-conversions,
unit-constructor1, unit-udt, unit-udt_macro, unit-regression1/2/3,
unit-deserialization, unit-noexcept, unit-items, unit-allocator,
unit-custom-object-type, unit-ordered_json2 and
unit-brace-init-copy-semantics pass at C++11, C++17 and C++20 with
unchanged assertion counts. Ran make amalgamate.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-01 07:37:47 +02:00
Niels Lohmann 5e93415d91 Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>

# Conflicts:
#	include/nlohmann/detail/input/lexer.hpp
#	include/nlohmann/detail/input/parser.hpp
#	single_include/nlohmann/json.hpp
#	tests/src/fuzzer-parse_json.cpp
2026-10-01 07:36:30 +02:00
Niels Lohmann cff0a61369 Share DOM SAX position handling; fix stale parser and lexer comments (#5731)
* Share the diagnostic-position setter of the DOM SAX parsers

json_sax_dom_parser and json_sax_dom_callback_parser each had a private
copy of handle_diagnostic_positions_for_json_value(), identical except
for comments. Move the body into one static member function,
detail::diagnostic_positions::set_from_lexer(value, lexer), which both
classes call with their lexer pointer. basic_json befriends the new
struct (only when JSON_DIAGNOSTIC_POSITIONS is enabled), as the position
members are private.

The discarded case is reached through the callback parser, so the
LCOV_EXCL markers that only the dom parser's copy had are gone. The
NOLINT on the unreachable default case loses the stray
"-warnings-as-errors", which is not a check name.

The start-position setup in start_object()/start_array() is left alone,
as #5706 is editing the callback parser's versions.

Behavior, the public API and the ABI are unchanged.

Part of #5712

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

* Correct the parser comments on recursion and skip_to_state_evaluation

The class documentation called the parser a recursive descent parser,
but sax_parse_internal() is a loop that keeps the open containers on an
explicit stack. The comment at the end of an array and of an object
said the flag is set to false while the code below it sets it to true.
Describe what the code does instead.

Comments only; behavior, the public API and the ABI are unchanged.

Part of #5712

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

* Update the discard_number_values comments to the current number path

The comments explaining the accept() shortcut in convert_number() and
the member documentation still argued in terms of strtoull()/strtoll()
and errno, which #5283 replaced with convert_integer(), and pointed at
scan_number() instead of convert_number(). They also did not say that
scan_number_bulk_contiguous() converts integers itself, so the shortcut
is only reached for input without bulk access, with
JSON_DIAGNOSTIC_POSITIONS, or when the bulk scanner falls back.

Rewrite both comments to describe the digit-count check in front of
convert_integer(), keeping the 18-digit bound and the json_sax_acceptor
argument. The stale <cstdlib> comment is left for after #5616, which
edits that include block.

Comments only; behavior, the public API and the ABI are unchanged.

Part of #5712

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

* List the UTF-8 validators instead of calling the DFA the only one

The documentation of decode() called the Hoehrmann DFA the single
source of truth for UTF-8 validation. It is used only by the serializer
and by is_valid_utf8() (CBOR/MessagePack/BSON/UBJSON/BJData text
strings). The lexer's scan_string() switch, validate_one_utf8() /
valid_utf8_prefix() (bulk string scan, BON8 bulk path and BON8 writer)
and the BON8 byte path in get_bon8_string() check the RFC 3629 ranges
on their own.

Replace the sentence with a list of the four validators, what each is
used for, and a note that they must accept the same sequences. Sharing
code between them was considered and dropped: it would save a few lines
in a validator that is entangled with BON8 pushback, and #5677 is
editing the BON8 byte path.

Comments only; behavior, the public API and the ABI are unchanged.

Part of #5712

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

* Fix stale doc comments and include lists in the input headers

input_adapters.hpp included <memory> and <numeric> for the removed
shared_ptr-based adapter design but used neither; it called
(std::min) without including <algorithm>. json_sax.hpp used
std::numeric_limits without including <limits>. Also corrected
comments that no longer matched the code: input_stream_adapter does
not skip the input's BOM (the lexer's skip_bom() does), the
span_input_adapter comment named the no-longer-existing
input_buffer_adapter type, lexer::get_string() does not reset the
token, binary_reader's get_number() doc opened with /* instead of
/*! (so Doxygen skipped it) and omitted BON8 from its endianness
note, and the UBJSON-binary-types note did not mention that BJData
'B' arrays are read as binary.

Left out: the lgtm suppression on lexer.hpp's scan_number() (in
#5616's hunk) and the "-1 if unknown" wording in json_sax.hpp's
start_object/start_array docs (in draft #5267's hunk), per the
verdict's conflict list.

Part of #5712

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

* Deduplicate the strict-EOF/release_lookahead/error block in parser::parse()

json_sax_dom_callback_parser and json_sax_dom_parser branches of
parser::parse() ran the same ~25 lines after sax_parse_internal():
the strict-mode EOF check (raising parse_error.101 through the SAX
parser), release_lookahead() in non-strict mode, and mapping an
errored SAX parser to a discarded result. The two copies had already
drifted apart in formatting and in the second copy's "see above"
comment.

Add a private parse_dom(DomSax&, strict) member that runs this shared
sequence once and returns whether the SAX parser did not error; both
branches of parse() now only construct their DOM SAX parser, call
parse_dom(), and (for the callback parser) map a discarded top-level
value to null. sax_parse() is left untouched, since it only runs the
EOF check and release_lookahead() when sax_parse_internal() succeeded,
unlike parse(), which runs them unconditionally.

Behavior-preserving: same operations in the same order for both SAX
parser kinds. Verified with unit-class_parser (strict/non-strict,
callback and non-callback), unit-deserialization and
unit-disabled_exceptions (JSON_NOEXCEPTION), plus a clean
make amalgamate / make check-amalgamation diff.

Overlaps #5601, which touches the same lines.

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

#5712 item 2

* Share the code point to UTF-8 encoding between the wide-string helpers and the lexer

The 1/2/3/4-byte UTF-8 encoding ladder was written out by hand three
times: in wide_string_input_helper<..., 4>::fill_buffer() for a UTF-32
code point, in the UTF-16 helper for both a BMP code unit and a valid
surrogate pair, and in the lexer's \uXXXX/\uXXXX\uYYYY handling. The
copies had drifted: the UTF-32 helper masked the leading bits of each
byte (& 0x1Fu, & 0x0Fu, & 0x07u) where the others relied on the shift
alone, even though both give the same result for a code point that is
already known to be in range.

Add detail::encode_utf8(cp, out) in string_utils.hpp, a single encoder
that invokes a callable once per output byte, most significant byte
first. Use it in the three valid-code-point branches (UTF-32 code
points up to U+10FFFF, UTF-16 code units outside the surrogate range,
and valid UTF-16 surrogate pairs) and in the lexer's \u handling, where
out forwards to add(). The UTF-16 helper's deliberate pass-through of
malformed surrogate units and the UTF-32 helper's 0xFF sentinel for
code points above U+10FFFF are untouched, since neither reaches the new
helper.

Behavior-preserving: same bytes in the same order for every valid code
point, verified with unit-class_lexer, unit-class_parser,
unit-deserialization, unit-wstring and the non-test-data parts of
unit-unicode1..5 (ASan/UBSan, C++11/17/20), and an escape-heavy parse
microbenchmark that shows no change (about 73 ms either way, median of
3, 1M escape sequences). single_include/ regenerated with make
amalgamate; make check-amalgamation leaves a clean tree.

Overlaps #5704, which rewrites the wide_string_input_helper
specializations touched here.

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

#5712 item 6

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-01 07:32:32 +02:00
Niels Lohmann 7e8e8e219b Merge remote-tracking branch 'origin/develop' into claude/fix-issue-3989-db7e45
Signed-off-by: Niels Lohmann <mail@nlohmann.me>

# Conflicts:
#	include/nlohmann/detail/input/binary_reader.hpp
#	include/nlohmann/json.hpp
#	single_include/nlohmann/json.hpp
2026-09-30 22:53:03 +02:00
Niels Lohmann c261578431 Deduplicate binary reader/writer helpers and fix stale comments (#5730)
* Fix stale and missing comments in binary_writer

The doc block of write_number() ended up above the byte_swap() helpers
added in #5286, about 80 lines from the function. It was also a plain
comment that Doxygen skips, said "write a number to output input", and
left BON8 out of the big-endian formats. Move it back onto
write_number() as a /*! block and fix the text.

write_bson() documented "@pre j.type() == value_t::object", but it
throws type_error.317 for every other type, and to_bson() relies on
that. Document the exception instead.

Explain why the CBOR binary subtype is always written with a 0xD8..0xDB
head and never in the one-byte tag form: binary_reader with
cbor_tag_handler_t::store only keeps those heads as a subtype, so
switching to write_cbor_head() would break round trips for subtypes
0..23.

Also fix the grammar of the to_char_type comment. Comments only; no
change in behavior, API or ABI.

Part of #5710

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

* Merge the duplicated UBJSON/BJData integer marker ladders

write_number_with_ubjson_prefix() (unsigned and signed overloads) and
ubjson_prefix() (number_integer and number_unsigned cases) each picked
the UBJSON/BJData integer marker (i, U, I, u, l, m, L, M, H) with their
own independent if/else ladder, and the values beyond 64 bits were
handled by a second, tag-dispatched pair of ladders. An optimized
container announces the marker of its first element via ubjson_prefix()
and then writes every element through write_number_with_ubjson_prefix(),
so the two had to be kept in lockstep by hand across four call sites.

Replace all of that with one ubjson_integer_prefix() built on
value_in_range_of<T>, and one write_ubjson_integer_payload() that
writes the value (or, for 'H', the decimal digits) for a given marker.
write_number_with_ubjson_prefix() and ubjson_prefix() keep their
signatures and now just call these two helpers.

Behavior, the public API and the ABI are unchanged. Verified with a
new regression test covering scalars and $-optimized arrays/objects at
every int8/uint8/int16/uint16/int32/uint32/int64/uint64 boundary for
to_ubjson/to_bjdata (both use_size/use_type settings), and by diffing
to_ubjson/to_bjdata output before and after over the json_test_data
corpus (bit-identical).

Part of #5710

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

* Remove dead get_char parameters in binary_reader

The non-recursive rewrite of the binary readers (#5505, #5506, #5507)
left parse_cbor_internal()'s and parse_ubjson_internal()'s get_char
parameters dead: parse_cbor_internal() has one caller and it always
passes true, and parse_ubjson_internal() has one caller and it always
uses the true default. Both parameters, and the @param docs describing
the "reuse the last character" mode they used to select, no longer
correspond to anything.

Drop both parameters, initialise fetch/prefix unconditionally, and
update the two call sites in sax_parse(). parse_cbor_value()'s and
get_ubjson_string()'s own get_char parameters are unrelated and are
left alone; both still have a false caller.

Also delete a stray `@return whether a valid MessagePack value was
passed to the SAX parser` doxygen block that sits directly above
parse_msgpack_value()'s real doc comment, a leftover of the same
rewrite.

Behavior, the public API and the ABI are unchanged; these are private
members of detail::binary_reader. Verified by compiling with
-Wunused-parameter and running unit-cbor, unit-ubjson, unit-bjdata and
unit-msgpack (offline, against the stubbed test_data.hpp).

Part of #5711

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

* Share the IEEE half-precision decoder between CBOR and BJData

binary_reader had two ~45-line copies of the IEEE 754 half-precision
decoder: CBOR's case 0xF9 and BJData's case 'h'. Once formatting is
normalised, the two blocks were identical except for the byte order
used to assemble the 16-bit half (CBOR is big endian, BJData is little
endian). Any future change to half-float decoding had to be made and
kept in sync in both places.

Add one get_half_float(format, little_endian) helper that does the two
get()/unexpect_eof() reads, assembles the half in the requested byte
order, decodes it per RFC 8949 Appendix D, and calls sax->number_float.
Both cases now just call it with their byte order; the BJData case
keeps its bjdata-only guard.

Behavior, the public API and the ABI are unchanged. Verified with a
scratch probe comparing the old and new decoders bit-for-bit (NaN by
isnan()) over all 65536 wire byte pairs, in both formats, and by
running unit-cbor and unit-bjdata (offline, against the stubbed
test_data.hpp).

Part of #5711

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

* Deduplicate the MessagePack unsigned-integer writer ladder

The number_integer (non-negative branch) and number_unsigned cases in
write_msgpack() each held their own copy of the fixint/uint8/16/32/64
ladder, kept in lockstep only by a comment ("we used the code from the
value_t::number_unsigned case here"). Both copies mixed union members:
the signed copy compared number_unsigned but wrote number_integer, and
vice versa.

Extract write_msgpack_unsigned(std::uint64_t), mirroring how
write_cbor_head() already avoids the same duplication for CBOR, and
call it from both cases. Each case now reads only its own active
union member. Output bytes are unchanged for the default 64-bit
number types.

#5710 item 3

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

* Unify float marker selection and fix the long double compile error

Four formats picked between a float32 and float64 marker through four
different helper styles: dummy-argument overloads for CBOR and
MessagePack, an std::is_same template for BON8, and a runtime if-chain
on input_format_t for write_compact_float(). With number_float_t set
to long double, to_cbor, to_msgpack and to_ubjson failed inside the
library with "call to 'get_cbor_float_prefix' is ambiguous", while
to_bson kept working because write_bson_double() takes a plain double.

Change write_compact_float() to take the two marker bytes directly
(each of its three callers already knows them at compile time) instead
of an input_format_t it only forwarded, and delete the now-unused
get_cbor_float_prefix(), get_msgpack_float_prefix(),
get_bon8_float_prefix() and get_compact_float_prefix() helpers. Turn
the two get_ubjson_float_prefix() overloads into one template. Both
write_compact_float() and get_ubjson_float_prefix() now report an
unsupported number_float_t with a static_assert naming the requirement,
rather than an ambiguous-overload error; the assert lives in the
function body, not the class scope, so to_bson with long double is
unaffected.

Verified with a probe basic_json<..., long double>: to_bson still
compiles and round-trips, while to_cbor/to_msgpack/to_ubjson now fail
to compile with the new static_assert message.

This changes the text of an existing compile error for users with an
unsupported number_float_t (documented as a public-API-visible change
in #5710).

#5710 item 1

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

* Deduplicate the BJData ndarray writer's dtype dispatch and drop <map>

write_bjdata_ndarray() built a 12-entry std::map<string_t, CharType> on
every call just to translate the _ArrayType_ name to a dtype marker
(the only reason binary_writer.hpp included <map>), then mapped dtype
to C++ type twice more: once as a switch for the range-check pass and
once as a separate if/else chain for the write pass, with nothing
checking that the two agreed. The caller also ran three at() lookups,
and the callee called value.at(key) about ten more times for the same
three members.

Replace the map with bjdata_ndarray_type_marker(), a plain string
comparison chain (a C++11 constexpr function cannot contain a switch,
so this mirrors binary_reader's own static table style). Replace the
switch/if-chain pair with one write_bjdata_ndarray_elements() that
switches on dtype once and calls a per-type helper -
write_bjdata_ndarray_element<T>() for the eight integer dtypes and
write_bjdata_ndarray_float_element() for 'd' - with a dry_run flag
selecting the range check or the actual write, so the two passes can
no longer disagree on the type. _ArrayType_, _ArraySize_ and
_ArrayData_ are now looked up once into references, and the four
header marker bytes ('[', '$', '#') are written through to_char_type()
like the rest of the UBJSON/BJData writer.

The 'd' (single-precision) rule is left exactly as before, since #5707
is expected to change it separately.

Verified byte-for-byte identical output before/after for every dtype
(including the Draft 2/Draft 3 'byte' fallback and the use_count/
use_type combinations) via a standalone probe, plus round-tripping
through from_bjdata().

Overlaps #5707, which is expected to touch the 'd' dtype case, and
#5518, which is expected to move the write_bjdata_ndarray() call site.

#5710 item 4

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

* Assert that write_bson_document() consumes every calc_bson_sizes() entry

calc_bson_sizes() and write_bson_document() are a hand-synchronized
pair of passes over the same object/array tree, introduced by #5553:
the size pass appends to nested_sizes in visiting order, and the write
pass consumes the table by position with nested_sizes[next_size++].
Nothing checked that the write pass consumed the whole table. If a
future change touched only one of the two passes - for example to skip
or reject an entry - every later size prefix in the document would be
silently wrong.

Add JSON_ASSERT(next_size == nested_sizes.size()) where
write_bson_document() returns, so such a future drift between the two
passes is caught immediately (JSON_ASSERT expands to nothing in
release builds using assert(), and the fuzzers/tests already build
with it enabled). The two passes agree today, so this changes nothing
observable; it only guards against the risk described in #5710 item 5.

Extracting a shared stepper for the two passes (the second half of the
proposed change) is left for a follow-up: it only saves ~30 lines and
the issue asks for it only if the result reads clearly, which needs
more room to get right than a mechanical cleanup pass allows.

#5710 item 5

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

* Make the BJData lookup tables static functions instead of members

binary_reader held bjd_optimized_type_markers and bjd_types_map as
non-static const members (12 string_t objects for the type-name table),
built and destroyed on every from_cbor/from_msgpack/from_bson/
from_ubjson/from_bon8/from_bjdata call even though only from_bjdata
ever reads them. They also needed the #define/decltype/#undef
workaround from #3637 and two NOLINTNEXTLINE suppressions, and
binary_writer already carries the same two lists in another form
(is_bjdata_excluded_type_marker() and a local std::map in
write_bjdata_ndarray(), the latter removed by the item-4 commit), so
the excluded-marker lists could drift apart.

Replace bjd_optimized_type_markers with static constexpr
is_bjd_excluded_optimized_type(char_int_type), using the same ||-chain
as binary_writer's is_bjdata_excluded_type_marker(). Replace
bjd_types_map with a non-constexpr static bjd_type_name(char_int_type)
switch returning nullptr for an unknown marker (a C++11 constexpr
function cannot contain a switch). Delete both
JSON_BINARY_READER_MAKE_* macros, the bjd_type pair alias, the
NOLINTNEXTLINE suppressions, detail::make_array() (no longer used
anywhere), and the now-unused <algorithm> and <array> includes.

Update the two call sites (the ND-array excluded-type check and the
_ArrayType_ lookup) accordingly, and replace unit-bjdata.cpp's
"LUT arrays are sorted" section, which only checked the two tables'
internal ordering, with a check of all 12 type names and all 8
excluded markers against both new functions.

#5711 item 1

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

* Read CBOR's 1/2/4/8-byte argument through one helper

parse_cbor_internal() hand-wrote the same "read a 1/2/4/8-byte
big-endian unsigned integer" ladder four times over:
- twice for tag numbers 0xD8-0xDB, once in the tag_handler::ignore
  branch and once, nearly identically, in the ::store branch (~90
  lines to read one integer);
- twice more for container lengths, once for array heads 0x98-0x9B and
  once for map heads 0xB8-0xBB, where the 1/2-byte forms called
  enter_array()/enter_object() directly and the 4/8-byte forms
  additionally went through get_cbor_container_size().

Add get_cbor_argument(std::uint64_t&), reading the width selected by
current & 0x1F via the same get_number() calls as before (so EOF is
reported exactly as before), and route all four sites through it:
- 0xD8-0xDB now read the argument once per branch instead of switching
  on `current` a second time; behavior split cleanly from embedded tags
  0xC0-0xD7 (tag value in the head, no argument to read), which is now
  its own case block that no longer has to fall into the ::store
  switch's "default" case to reach the same tag_pending = true; return
  true; outcome.
- 0x98-0x9B and 0xB8-0xBB collapse into one case block each, always
  going through get_cbor_container_size() (harmless for 1/2-byte
  lengths, which already always fit).

Verified byte-for-byte identical behavior before/after with a
standalone probe covering embedded and multi-byte tags under all three
tag_handler_t settings, a tag over a byte string (subtype path),
truncated tag/length arguments of every width, and array/map lengths
of every width, including the out_of_range.408 "excessive size" case:
same exceptions, same messages, same chars_read, same successful
results.

Left the string/byte-string length ladders in get_cbor_string()/
get_cbor_binary() untouched, as noted in #5711 item 2, since #5325 is
expected to touch them separately.

Overlaps #5601 (adds a branch right above the embedded-tag case) and
#5607 (touches the integer cases 0x18-0x1B, which share this ladder's
shape in separate hunks).

#5711 item 2

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

* Add leave_container() to match enter_container()

Every container is opened through enter_container(), whose docs
promise that a check placed there runs before every start event. The
close side had no equivalent: the same
"container_stack.pop_back(); dispatch to end_object() or end_array()"
sequence was written out separately in BSON, CBOR, MessagePack,
UBJSON/BJData and BON8, each copying the pattern of keeping an
is_object flag around the pop_back() that would otherwise invalidate
a reference to it. A check needed on close would have had to be added
in five places, and a sixth copy could go unnoticed.

Add leave_container() next to enter_container(), doing the same
pop-then-dispatch, and replace the five sites with it. Each site keeps
its own surrounding logic (BSON's check_bson_document_size() call
before popping, MessagePack's is_object copy used again below,
UBJSON/BJData's remaining-container handling after popping, BON8's
top used again below); only the repeated pop/dispatch line pair is
now shared.

Verified all six binary-format unit suites and unit-regression2's
deep-nesting tests (dependent count/reuse count and the bjdata ndarray
depth cases) still pass, compiled with -Wall -Wextra and ASan/UBSan.

Overlaps #5601, which is expected to add a sixth close site in its own
skip loop; that site can route through leave_container() too once it
lands.

#5711 item 4

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

* Stop passing the input format to sax_parse() when the reader already has it

binary_reader's constructor stores the format in the input_format
member, and sax_parse(format, sax_, strict, tag_handler) took the same
value again purely to dispatch on it. Every in-tree caller passed the
same value both times (all 16 from_cbor/from_msgpack/from_ubjson/
from_bjdata/from_bon8/from_bson call sites in json.hpp, and the three
public basic_json::sax_parse() overloads), so nothing was broken
today, but a caller of the detail class directly (only reachable via
JSON_PRIVATE_UNLESS_TESTED, as unit-bjdata.cpp already does) could
pass a mismatched pair - say bjdata to the constructor and ubjson to
sax_parse - and dispatch on one format while applying the other
format's rules; the default-constructed input_format_t::json reader
would additionally hit JSON_ASSERT(false) in exception_message() on
its first error.

Add sax_parse(json_sax_t*, bool, cbor_tag_handler_t) forwarding to the
existing overload with the stored input_format, and switch every
caller to it: the 16 from_*() sites (keeping their
`// cppcheck-suppress[accessMoved]` comments) and the three
basic_json::sax_parse() overloads, all of which already had the format
available from their own `format` parameter. The four-argument overload
is kept for anyone still calling it, now with
JSON_ASSERT(format == input_format) so a mismatch fails immediately
in a debug build (assert-enabled binaries, including the fuzzers and
test suite) instead of misbehaving; verified with a probe that
constructs a reader for one format and calls the explicit overload
with another, which aborts on that assertion as expected.

Removing or asserting against the constructor's input_format_t::json
default, which would affect direct detail users, is left as a separate
decision per #5711 item 5.

Overlaps #5601, which is expected to add an AllowRecovery template
parameter to sax_parse() and touch these same call sites in json.hpp.

#5711 item 5

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

* Deduplicate UBJSON/BJData signed-count handling, drop dead ndarray checks

get_ubjson_size_value()'s 'i'/'I'/'l'/'L' cases each read a differently
sized signed integer and then repeated the same "reject negative with
error 113" check; only 'L' additionally checked value_in_range_of for
the out_of_range.408 case. Any change to that error path had to be
made four times.

Add get_ubjson_signed_count<SignedType>(std::size_t&), doing the read,
the negative check and the range check once, and route all four
markers through it. The range check is a no-op for 'i'/'I'/'l' (their
values always fit std::size_t) and only live for 'L' on a 32-bit
std::size_t target, matching today's behavior exactly.

In the ndarray dimension-product loop, the preceding loop already
returns early on any zero dimension and result starts at 1, so `i > 0`
in the pre-multiplication overflow check was always true, and
`result == 0` in the post-multiplication check could not be reached
either: two positive factors whose product does not overflow (as the
pre-check already guarantees) cannot be zero. Drop the dead `i > 0 &&`
and narrow the post-check to `result == npos`, the one case the
pre-check cannot rule out (an exact, non-overflowing match with the
sentinel reserved for unknown-size containers), with a comment
explaining why.

Verified byte-for-byte identical behavior before/after with a
standalone probe covering negative counts for every marker, a matching
positive count, and ndarray inputs, plus the full unit-ubjson and
unit-bjdata suites (same assertion counts as before this change).

Overlaps #5601 (rewrites the four parse_error calls and the overflow
checks touched here) and #5607/#5707 (touch neighboring lines in the
same functions).

#5711 item 6

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

* Drop redundant format parameter and dummy float argument (review)

binary_reader::sax_parse(format, ...) only ever had to equal the format
given to the constructor, which it asserted. With every caller already
on the format-less overload, remove the four-argument overload and
dispatch on the stored input_format directly. binary_reader is a
detail class, so this is not a public API change.

get_ubjson_float_prefix() took a value only to deduce its type; make
the type an explicit template argument instead.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-30 22:48:32 +02:00
Niels Lohmann 792853d725 Fix CI: clang-tidy and JSON_NOEXCEPTION in the #3989 changes
ci_clang_tidy flagged nested conditional operators in the BON8 skip
code and in remove_incomplete_utf8_sequence()
(readability-avoid-nested-conditional-operator), and two branches with
the same body in recover_string() (bugprone-branch-clone). Use if
chains instead of the nested conditionals and merge the two branches
into one condition; the short-circuit order is unchanged.

ci_test_noexceptions aborted in the #3989 regression test: it compares
the first recovered error with the message of the exception that
from_cbor() and friends throw, and under JSON_NOEXCEPTION that call
aborts instead of throwing. Guard binary_error_message() and its uses
with #if !defined(JSON_NOEXCEPTION), as other tests in the suite do.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-29 16:42:57 +02:00