19 Commits
Author SHA1 Message Date
Niels Lohmann 1e44262091 Make JSON_STRICT_NUL_HANDLING part of the ABI tag (#5560)
* Make JSON_STRICT_NUL_HANDLING part of the ABI tag

JSON_STRICT_NUL_HANDLING (#5534) changes the bodies of inline functions:
the lexer's handling of '\0' and input_adapter() for char arrays. So
translation units compiled with and without it define the same functions
differently, an ODR violation - the case the ABI tag exists for, as with
JSON_BRACE_INIT_COPY_SEMANTICS (_bics). It now appends _snul to the inline
namespace. The macro is new in 3.13.0, so no existing namespace changes.

Its default moves to abi_macros.hpp, and it is only #undef'd without
JSON_TEST_KEEP_MACROS, as for the other ABI macros. The ABI config tests,
the namespace docs, the macro's docs and the Natvis file cover the new tag.

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

* Amalgamate

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-25 21:54:11 +02:00
Niels Lohmann abbe52d6de Add JSON_PRECISE_STREAM_POSITION to leave the character that terminates a number in the stream (#5344)
* docs: qualify the operator>> stream positioning guarantee

operator>>'s notes state that it leaves the stream positioned right
after the parsed value, so that concatenated JSON values can be read
back to back. That does not hold when the value is a number: a number
is only terminated by the character that follows it, and the lexer's
unget() is simulated (it rewinds only the lexer's own bookkeeping),
so that character stays consumed from the stream.

Document the actual behaviour: the guarantee holds for all value types
except numbers, which must be followed by whitespace. Also qualify the
cross-reference on the JSON Lines page, which repeated the unqualified
claim.

Documentation only; the behaviour itself is tracked in #5340.

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

* fix: restore the character that terminates a number (#5340)

operator>> is documented to leave the stream positioned right after the
parsed value, so that concatenated JSON values can be read back to back.
That did not hold for numbers: a number is only terminated by the
character following it, and lexer::scan_number() reads that character
and calls unget() -- which is simulated and rewinds only the lexer's own
bookkeeping. input_stream_adapter consumes via sbumpc() with no matching
sungetc(), so the terminating character stayed consumed and the next
extraction started one byte too late ('1true' left the stream at 'rue').

Propagating unget() to the adapter directly does not work: next_unget
makes the following get() replay the cached character, so the terminator
would be delivered twice. Instead, restore the still-pending character
once at the end of a non-strict parse, where the input is handed back to
the caller:

- input_stream_adapter gains unget_character() (sungetc()) and advertises
  it via supports_unget, detected the same way as supports_seek.
- lexer::restore_pending_unget() turns a pending simulated unget of a
  real (non-EOF) character into a real one and clears next_unget so the
  character is not also replayed. It is a no-op for adapters that cannot
  unget, and reports failure when sungetc() fails, in which case the
  input is left as it was before.
- parser calls it on the three non-strict paths, i.e. for operator>> and
  sax_parse(strict = false).

Strict parse()/accept() are unaffected: they require the input to end
after the value, so the character is consumed by the end-of-input check
anyway. Parse error messages and reported positions are unchanged.

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

* tests: fix CI failures in the #5340 test helpers

Four CI failures, all in the new test code:

- GCC (-Werror=useless-cast): drop the `json(...)` wrapper around
  `json::parse(...)`, which already returns a `json`.
- GCC (-Werror=unused-result): assign the discarded `json::parse()`
  result to a dummy, the idiom used elsewhere in the test suite, and
  catch `json::parse_error&` for consistency.
- clang-tidy (google-default-arguments): remove the default argument
  from the `pbackfail()` override; `sungetc()` supplies the base
  declaration's default.
- MSVC (bad allocation): `no_putback_streambuf::underflow()` set a
  one-character get area without advancing `m_pos`, so an implementation
  whose `istream::get` peeks before it bumps re-read the same character
  forever. Keep no get area at all: `underflow()` peeks, `uflow()`
  consumes, and `sungetc()` still always lands in `pbackfail()`, which
  is what the test needs.

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

* fix: leave the character that terminates a number in the input

Read the character following a number without consuming it, instead of
consuming it and putting it back. input_stream_adapter now peeks with
sgetc() and only steps over the character when the next one is requested
or when the adapter is destroyed, so releasing it cannot fail - no
putback position is required from the streambuf.

Suggested by gregmarr in #5344.

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

* docs: match the version history wording to the peek-based fix

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

* docs: drop the whitespace-separator caveat from the parsing pages

The caveat added in #5343 describes the behavior this branch fixes: a
number no longer consumes the character that terminates it, so
concatenated values need no separator.

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

* refactor: split the strict and non-strict paths in parser

Folding the release_lookahead() call into the existing strict check left
the "in strict mode" comment on an else-if branch, and made the strict
condition in sax_parse() redundant with the branch it followed.

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

* Put the stream position fix behind JSON_PRECISE_STREAM_POSITION

Leaving the character that terminates a number in the stream is observable:
reading "1,2,3" with repeated operator>> works today only because the comma
after each number is swallowed, and std::getline after a number skips the
line break. Both break with the fix, so make it opt-in for 3.x, as suggested
by @gregmarr in the review.

- JSON_PRECISE_STREAM_POSITION (default 0) selects the peek-based
  input_stream_adapter. Without it, the adapter is the consuming one from
  develop and has no supports_lookahead, so lexer::release_lookahead() and
  the parser's calls to it compile to nothing.
- The macro changes input_stream_adapter's layout and member functions, so
  it gets the ABI tag _psp, after _bics. The ABI config tests, the natvis
  generator, and nlohmann_json.natvis (regenerated) know the tag.
- The tests for the fix move to unit-precise-stream-position.cpp, which
  defines the macro itself and runs in every build, and gain the two cases
  above. unit-deserialization.cpp pins the default behavior instead.
- The docs describe the default behavior again and point to the new macro
  page; version history says "added in 3.13.0, planned default in 4.0.0".

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-25 17:56:18 +02:00
Niels Lohmann 2e91641de2 Test JSON_BRACE_INIT_COPY_SEMANTICS for real, and fix one-element tuples under it (#5544)
* Test JSON_BRACE_INIT_COPY_SEMANTICS for real, and fix one-element tuples under it

The opt-in JSON_BRACE_INIT_COPY_SEMANTICS was never exercised by CI:

- Its only test, in unit-regression3.cpp, was guarded by
  `#if defined(JSON_BRACE_INIT_COPY_SEMANTICS)` after the #include. The
  header #undefs the macro unconditionally in macro_unscope.hpp, so the
  guard was always false and the test compiled to nothing, whatever -D
  flag was passed.
- The ci_test_brace_init_copy_semantics target that passes the flag was
  not named by any workflow.

Move the test into its own translation unit that defines the macro before
including the header, as unit-diagnostics.cpp does for JSON_DIAGNOSTICS.
It now runs in every CI job and for every standard. Remove the unused
target: it ran the whole suite with the macro, and that suite deliberately
relies on default brace-init semantics in about 90 places
(e.g. `json({1})` meaning `[1]`), so it could never pass.

Running the whole suite with the macro did find one library bug:
to_json for std::tuple builds `j = { std::get<Idx>(t)... }`, so with copy
semantics a one-element tuple became its element. `json(std::tuple<int>{5})`
was `5` instead of `[5]`, and `get<std::tuple<int>>()` threw type_error.302
on the result. Under the macro, a one-element tuple now builds exactly what
the default deduction builds. Without the macro nothing changes.

The new tests also pin that the library's other conversions produce the
same values with and without the macro. The macro page now says that the
macro affects every single-element list (`json j = {1}` is `1`), and that
all translation units must agree on it, since it has no ABI tag.

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

* Make JSON_BRACE_INIT_COPY_SEMANTICS part of the ABI tag

The macro changes the body of the initializer-list constructor and adds a
to_json_tuple_impl overload, both with the same mangled names in either
mode, so mixing translation units silently picked one definition. Encode
it in the inline namespace as `_bics`, as JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON
does with `_ldvcmp`. The macro is new in the unreleased 3.13.0, so no
existing namespace name changes.

- Move the macro's default into abi_macros.hpp so json_fwd.hpp computes
  the same namespace, and keep it defined under JSON_TEST_KEEP_MACROS.
- Check the tag in the ABI config tests and in the unit test.
- List `_bics` (and the missing `_dp`) in the namespace docs and in the
  natvis generator; regenerate nlohmann_json.natvis.
- Replace the "define it consistently" warning with an ABI note.

Suggested by @gregmarr in the review of #5544.

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

* Fix the cppcheck, clang-tidy and legacy-comparison CI failures

- to_json_tuple_impl() moved the element in both branches of a ternary;
  only one runs, but cppcheck reported accessMoved. Use if/else.
- The ABI tag test looked for "json_abi_bics", which misses when another
  tag comes first, as in json_abi_ldvcmp_bics; look for "_bics".
- readability-qualified-auto in the items() test.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-24 17:05:37 +02:00
Niels Lohmann 515d994acb 📄 adjust year (#5044)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-01-01 20:00:39 +01:00
Niels Lohmann 54be9b04f0 📄 update REUSE (#4960) 2025-10-23 06:56:36 +02:00
Niels Lohmann 1705bfe914 🔖 set version to 3.12.0 (#4727)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2025-04-11 10:41:14 +02:00
Niels Lohmann f06604fce0 Bump the copyright years (#4606)
* 📄 bump the copyright years

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

* 📄 bump the copyright years

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

* 📄 bump the copyright years

Signed-off-by: Niels Lohmann <niels.lohmann@gmail.com>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Signed-off-by: Niels Lohmann <niels.lohmann@gmail.com>
2025-01-19 17:04:17 +01:00
Sushrut ShringarputaleandSush Shringarputale 58f5f25968 json start/end position implementation (#4517)
* Add implementation to retrieve start and end positions of json during parse

* Add more unit tests and add start/stop parsing for arrays

* Add raw value for all types

* Add more tests and fix compiler warning

* Amalgamate

* Fix CLang GCC warnings

* Fix error in build

* Style using astyle 3.1

* Fix whitespace changes

* revert

* more whitespace reverts

* Address PR comments

* Fix failing issues

* More whitespace reverts

* Address remaining PR comments

* Address comments

* Switch to using custom base class instead of default basic_json

* Adding a basic using for a json using the new base class. Also address PR comments and fix CI failures

* Address decltype comments

* Diagnostic positions macro (#4)

Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>

* Fix missed include deletion

* Add docs and address other PR comments (#5)

* Add docs and address other PR comments

---------

Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>

* Address new PR comments and fix CI tests for documentation

* Update documentation based on feedback (#6)

---------

Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>

* Address std::size_t and other comments

* Fix new CI issues

* Fix lcov

* Improve lcov case with update to handle_diagnostic_positions call for discarded values

* Fix indentation of LCOV_EXCL_STOP comments

* fix amalgamation astyle issue

---------

Co-authored-by: Sush Shringarputale <sushring@linux.microsoft.com>
2024-12-18 22:46:14 +01:00
Niels Lohmann 1b9a9d1f21 Update licenses (#4521)
* 📄 update licenses

* 📄 update licenses
2024-11-29 17:38:42 +01:00
Niels Lohmann 1825117e63 Another desperate try to fix the CI (#4489)
* 🚨 fix warning

* 💚 update actions

* 🚨 fix warning

* 🚨 fix warning

* 🚨 fix warning

* 💚 update actions

* 💚 update actions

* 🚨 fix warning

* 🚨 fix warning

* 💚 update actions

* 🚨 fix warning

* 💚 update actions

* 💚 update actions

* 💚 update actions

* 🚨 fix warning

* 🚨 fix warning

* 🚨 fix warning

* 🚨 fix warning

* 💚 update actions

* 💚 update actions

* 🚨 fix warning

* 💚 update actions

* 💚 update actions

* 💚 update actions

* 💚 update actions

* 💚 update actions
2024-11-13 10:21:26 +01:00
Niccolò IardellaandNiccolò Iardella aff5a31d35 Add NLOHMANN_DEFINE_DERIVED_TYPE_* macros (#4033)
* Add NLOHMANN_DEFINE_DERIVED_TYPE_* macros

* Fix with amalgamate

* Add documentation

* Fix with amalgamate

* Fix with amalgamate

---------

Co-authored-by: Niccolò Iardella <niccolo.iardella@doriansrl.it>
2024-11-08 21:41:19 +01:00
Niels Lohmann 9cca280a4d JSON for Modern C++ 3.11.3 (#4222) 2023-11-28 22:36:31 +01:00
Niels Lohmann f56c6e2e30 Update documentation for the next release (#4216) 2023-11-26 15:51:19 +01:00
Niels Lohmann 1ce29fa22f Fix CI (#4160) 2023-09-23 17:19:28 +02:00
Niels Lohmann 836b7beca4 Fix CI, again (#4083) 2023-09-07 20:41:12 +02:00
bed648ca55 Allow custom base class as node customization point (#3110)
Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com>
Co-authored-by: Florian Albrechtskirchinger <falbrechtskirchinger@gmail.com>
Co-authored-by: barcode <barcode@example.com>
2022-08-28 13:59:07 +02:00
Niels Lohmann 9d69186291 🔖 set version to 3.11.2 2022-08-12 15:04:06 +02:00
Florian Albrechtskirchinger 0e61ee8b07 Restructure inline namespace and allow version component to be disabled (#3683) 2022-08-10 20:24:16 +02:00
Florian Albrechtskirchinger 231f3108ff Amalgamate the forward declaration header (#3679)
* Amalgamate the forward declaration header

* Update CONTRIBUTING and PULL_REQUEST_TEMPLATE

* Update documentation
2022-08-07 13:57:32 +02:00