Commit Graph
4 Commits
Author SHA1 Message Date
satelliteprogrammer 40a62947d3 support JSON Merge Patch (RFC 7396) diff creation (#4965)
* support JSON Merge Patch (RFC 7396) diff creation

The JSON merge patch document format describes the set of modifications
to a resource's content, that more closely mimics the syntax of the
resource being modified.

However, and in contrast to JSON Patch (RFC 6902), a JSON Merge Patch
cannot express certain modifications, e.g., changing an array element
at a specific index, or setting a specific object value to null.
The null value in a JSON Merge Patch is used to remove the key from the
object.

The diff algorithm is not part of the RFC 7396, but it was tested
against all examples provided, plus additional cases on how null values
are handled.

Signed-off-by: Luís Murta <luis@murta.dev>

* improve algorithm efficiency

Signed-off-by: Luís Murta <luis@murta.dev>

* fix inconsistent nulls and empty arrays

Also add CHECKs for the patch, documentation and run `make amalgamate`.

Signed-off-by: Luís Murta <luis@murta.dev>

* documentation cleanups

Signed-off-by: Luís Murta <luis@murta.dev>

* add an iterative fallback to merge_diff

Bound the recursion depth like diff() and merge_patch(), and test values
nested past the bound.

Signed-off-by: Luís Murta <luis@murta.dev>

* address the remaining review comments

Signed-off-by: Luís Murta <luis@murta.dev>

* move multi-line raw strings out of CHECK macros

GCC 4.8/5, ICPC and NVHPC mis-tokenize multi-line raw string literals
inside macro arguments, breaking the build or the parsed JSON.

Signed-off-by: Luís Murta <luis@murta.dev>

---------

Signed-off-by: Luís Murta <luis@murta.dev>
2026-10-12 09:33:43 +02:00
Niels Lohmann 11ef352511 Point users to update(…, true), JSON Pointer defaults, and built-in std::optional (#5804)
A code search of client code found many hand-written versions of
functionality the library already has: recursive object merges
(update(j, true) since 3.10.5), dotted-path getters (value() and
contains() with a JSON Pointer), get_or helpers (value() throws for a
member that is present but null), and adl_serializer specializations
for std::optional (supported since 3.12.0).

- modifying_values.md: describe both modes of update(), add a
  defaults + user settings recipe, and stop recommending Merge Patch
  for recursive merges.
- merge_patch.md: note that null deletes keys, so a merge patch is not
  a general deep merge; link update().
- default_value.md: add "Nested values" (value/contains with a JSON
  Pointer, building a pointer from a dotted path with operator/=) and
  a warning that null and mistyped members are not missing.
- value.md: note that a null member is converted, not replaced by the
  default.
- json_pointer.md: link value/contains/at with JSON Pointers.
- arbitrary_types.md: note that std::optional needs no serializer.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-11 08:22:10 +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
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