* 📝 Document a duplicate-object-key rejection recipe
RFC 8259 leaves handling of duplicate object keys to the implementation;
this library silently keeps only the last value for a repeated key.
Discussion #5085 asked for an opt-in rejection mode. Decision: don't
change library behavior, but document the existing parser-callback
workaround instead.
Adds a "Recipe: rejecting duplicate object keys" section to
parser_callbacks.md, adapted from a community-contributed workaround.
Fixed an off-by-one bug in the original snippet: object_start reports
the depth of the object's parent, while key events inside that object
report depth+1, so indexing the per-depth key set with the same depth
in both places caused an out-of-bounds access on nested objects.
Verified the published snippet compiles and behaves correctly for flat
duplicates, nested duplicates, sibling objects sharing key names, and
arrays of objects.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Cross-link the duplicate-key recipe with the existing object_t behavior docs
object_t.md and features/types/index.md already document that duplicate
object keys resolve to an unspecified value (RFC 8259 leaves this to the
implementation). The new recipe's intro overstated this as a guaranteed
"last value wins" rule, which isn't true in general -- parsing text keeps
the last value, but constructing from an initializer list keeps the first.
Reworded the recipe to point at object_t's "unspecified" behavior instead
of asserting a specific rule, and added cross-links from both existing
pages to the new recipe.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Turn the duplicate-key recipe into a standalone, compiled example
Replace the inline code fence in the "rejecting duplicate object keys"
recipe with a proper docs/mkdocs/docs/examples/*.cpp + .output pair,
included via --8<-- like every other example on the site. The .output
file was generated by running it through the project's actual example
build (docs/Makefile: single_include, -std=c++11, -DJSON_USE_GLOBAL_UDLS=0)
and cross-checked with `make check_output`, and the source passes the
pinned astyle 3.4.13 formatting unchanged.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
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Signed-off-by: Niels Lohmann <mail@nlohmann.me>
When converting objects or strings between different basic_json specializations,
the target's object_t::key_type or string_t must be directly constructible from
the source's corresponding type. If this requirement is not met, the conversion
silently falls back to the array-conversion path, producing incorrect results.
This documents the limitation and provides references to issue #3425, which tracks
this behavior. The comment in unit-alt-string.cpp is clarified to reference the
known limitation with a link to the issue, and suggests the parse() workaround.
Fixes#3425 (documentation; full fix deferred pending type-trait redesign)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann