Commit Graph
9 Commits
Author SHA1 Message Date
Niels LohmannandMuhammad Amir bin Mohamad Ghazaly 8c1f60a45e Store maps with enum keys as objects (opt-in) (#5600)
* Store maps with enum keys as objects (opt-in)

Maps with enum keys, such as std::map<E, T>, are stored as arrays of
[key, value] pairs, because enums are not convertible to the string type
of object keys - even if NLOHMANN_JSON_SERIALIZE_ENUM maps them to
strings (#4378).

The new JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS macro stores them as objects
instead, converting each key with the enum's to_json. It applies to any
map-like type with enum keys (std::map with any comparator,
std::unordered_map, ...). A key that does not convert to a string throws
type_error.302, and two keys converting to the same string throw the new
type_error.318, rather than losing an entry. The macro changes the output
of inline functions, so it is part of the ABI tag (_ekmo).

Reading needs no macro: std::map and std::unordered_map with enum keys
are now also read from objects, converting each key with the enum's
from_json. That input was rejected before, and arrays of pairs are still
read, so data written either way can be read.

This supersedes #4531, which first proposed storing these maps as
objects.

Co-authored-by: Muhammad Amir bin Mohamad Ghazaly <amirghaz@umich.edu>
Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Keep multimaps with enum keys as arrays of pairs

With JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS, is_enum_keyed_map also matched
std::multimap and std::unordered_multimap. Storing them as objects throws
type_error.318 as soon as a key occurs twice, which is the normal case for
a multimap, so such values could no longer be serialized at all once the
macro was enabled, although they are stored losslessly as arrays of
[key, value] pairs without it.

Exclude maps with non-unique keys from is_enum_keyed_map. They are
detected by insert(value_type) returning an iterator rather than a
pair<iterator, bool>. Map-like types without such an insert() are still
treated as before.

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

* Move the default enum-keyed map tests out of unit-conversions.cpp

The Windows clang 20.1.8 job (MinGW, Debug) failed to link
test-conversions_cpp17 with "relocation truncated to fit:
IMAGE_REL_AMD64_REL32 against .rdata": the object file of
unit-conversions.cpp was already close to the limit, and the new
"maps with enum keys" test case pushed it over. windows.yml asks to keep
these objects small by splitting test files.

Move the test case unchanged into unit-enum_keyed_maps_default.cpp,
with the three enums it needs. It still honors a -D flag for
JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS, as before. unit-conversions.cpp
is back to its state on develop.

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

* Build the enum-keyed map test object instead of parsing it

ci_test_diagnostic_positions failed in unit-enum_keyed_maps_default.cpp:
with JSON_DIAGNOSTIC_POSITIONS, a parsed value adds its byte range to
the exception message ("(bytes 0-7) type must be array, but is
object"), so the exact-message checks did not match. Build the object
in memory, like unit-custom-array-type.cpp does.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Co-authored-by: Muhammad Amir bin Mohamad Ghazaly <amirghaz@umich.edu>
2026-10-04 17:54:05 +02:00
Niels Lohmann 63c10a51fc Review and extend the documentation, and check it in CI (#5638)
* Review and extend the documentation, and check it in CI

A review of all documentation pages found factual errors, dead links,
missing cross-references, and gaps in examples. This fixes them and adds
checks so the same problems are caught automatically.

Fixes:
- wrong signatures and version histories (operator!= C++20 member,
  binary() subtype type, get<PointerType>(), JSON_NO_THREAD_LOCAL, ...)
- stale descriptions (number parsing since #5283, UBJSON table, SAX
  example that no longer compiled, tsl::ordered_map advice)
- dead internal and external links; repology.org badges (the domain is
  suspended) replaced by badges that query the registries directly
- deprecation notes link the migration guide; the guide itself fixed

Additions:
- "See also" sections, cross-references, 25 runnable examples, 12
  Mermaid diagrams, new API pages for json_pointer::operator<=> and
  byte_container_with_subtype::operator==/!=
- landing page, guides for untrusted input and performance
- "unreleased" badge after versions newer than the latest release

Checks:
- strict documentation build (broken links/anchors fail it); CI and
  the publish workflow fetch the full history the build needs
- weekly external link check, Mermaid syntax check in CI
- check_structure.py: example titles, heading levels, alt texts,
  header links, docset index coverage; its unused-example check works
  again
- all examples produce the same output on every platform

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

* Keep the customer links that could not be fixed

A dead link on the customers page is still the evidence of where the
use of the library was documented. Keep the original URLs of the entries
without a working replacement (Marne, Cisco Webex Desk Camera, Philips
Hue, CyberArk) and exclude exactly these URLs from the link check.

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

* Correct the duplicate-key recipe's claim about SAX positions

The SAX interface's key() receives no position either; only parse_error()
does. Also note that the recipe does not report the path to the repeated
key (see discussion #5085).

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

* Say the library is available as a single header and mention json_fwd.hpp

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

* Correct documentation errors found while hunting for bugs

- patch/patch_inplace: list the JSON pointer errors parse_error.106-109
  and out_of_range.402/404, and quote the actual parse_error.105 message.
- unflatten: list parse_error.106/107/108 and out_of_range.404.
- to_bson: list out_of_range.415 (binary subtype above 255) and note
  that 412 and 415 are new in 3.13.0.
- to_string: state that string_t must be convertible to std::string, also
  in the StringType requirements table.
- JSON Lines: a `while (input >> j)` loop also throws after the last value
  for concatenated JSON values; show a loop that works for both.
- BON8: a string gets 0xFF only if nothing follows it in the message; a
  string at the end of an array or object is ended by 0xFE.
- custom_string_type.hpp: add operator+=(char), which the "Always
  required" list asks for (json_pointer::to_string, flatten, unflatten,
  and diff did not compile), and an ADL int_to_string for diff and items.

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

* Cache the release headers with functools.lru_cache

Codacy (Pylint) flagged the mutable default argument that header() used
as its cache. functools.lru_cache keeps the same memoization without it.
The script's output is unchanged.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-02 11:32:15 +02:00
Caillin NugentandNiels Lohmann 58cfecf7f7 Serialize enum (#5151)
* Added NLOHNMANN_JSON_SERIALIZE_ENUM_STRICT
- duplicate of NLOHMANN_JSON_SERIALIZE_ENUM

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* Added failing tests for NLOHMANN_JSON_SERIALIZE_ENUM_STRICT

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* modified NLOHMANN_JSON_SERIALIZE_STRICT to throw

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* added documentation and changed readme to include NLOHMANN_JSON_SERIALIZE_ENUM_STRICT

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* ran amalgamate

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* docs(macros): add page for JSON_SERIALIZE_ENUM_STRICT
- added page to nav
- added links to new page where appropriate

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* refactor(macros): make JSON_SERIALIZE_ENUM_STRICT use JSON_THROW
- added templated wrapper function to fix scope error in calling JSON_THROW

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* refactor(macros): make NLOHMANN_SERIALIZE_ENUM_STRICT use error code 410
- added error code 410 to docs

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* tests(macros): add test for to_json with enum value not mentioned
	       in mapping for NLOHMANN_JSON_SERIALIZE_ENUM_STRICT

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* Apply suggestions from code review

Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com>
Signed-off-by: Caillin Nugent <nugentcaillin@gmail.com>

* fix(macro): prevent compilation error with -Werror and -Wunused-parameter
            with NLOHMANN_JSON_SERIALIZE_ENUM_STRICT
- casted exception to void to avoid warning

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* fix(docs): add link to NLOHMANN_SERIALIZE_ENUM_STRICT docs to exception page

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* docs(macros): add example of exception throwing for NLOHMANN_JSON_SERIALIZE_ENUM_STRICT

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

* refactor(macros): add more in-depth error message to NLOHMANN_JSON_SERIALIZE_ENUM_STRICT
- changed error message to follow style of nlohmann/json#4989
- made description of throw wrapper more general
- updated tests and example of exceptions

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>

---------

Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au>
Signed-off-by: Caillin Nugent <nugentcaillin@gmail.com>
Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com>
2026-05-18 20:37:07 +02:00
Andy Choi cda9c1e3bd Use get instead of template get in REAMD.md and docs in non-template context (#4846)
Signed-off-by: Andy Choi <ccpong516@gmail.com>
2025-10-30 10:23:04 +01:00
Niels Lohmann 9110918cf8 Fix typos (#4748)
* ✏️ fix typos

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

* ✏️ address review comments

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

* ✏️ address review comments

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2025-05-04 10:28:24 +02:00
Niels Lohmann 4424a0fcc1 📝 update documentation (#4723)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2025-04-05 18:54:35 +02:00
Noandtusooa c71ecde505 Use template get instead of get in examples (#4039)
Co-authored-by: tusooa <tusooa@kazv.moe>
2023-06-11 10:06:24 +02:00
Richard Hozák f6acdbec2c Allow disabling default enum conversions (#3536) 2022-06-16 19:34:32 +02:00
Niels Lohmann b21c345179 Reorganize directories (#3462)
* 🚚 move files
* 🚚 rename doc folder to docs
* 🚚 rename test folder to tests
2022-05-01 09:41:50 +02:00