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json/tests
Niels Lohmann dd2dd45abd Fix false GCC -Warray-bounds error with JSON_DIAGNOSTICS at -O3 (#5744)
* Re-amalgamate single_include after #5737

#5737 changed sources under include/ without regenerating single_include,
so the single header on develop is out of date. This commit only runs
make amalgamate.

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

* Suppress GCC's false -Warray-bounds error in set_parents() with JSON_DIAGNOSTICS

With JSON_DIAGNOSTICS, GCC 13 to 15 report a false -Warray-bounds error
at -O3 when set_parents() is inlined right after a non-container value
(e.g., a string) was created: the std::map access in the object branch
is checked against the string allocation although m_type rules that
branch out. GCC 15 fixed the pattern from #4819 but not this one.

Suppress -Warray-bounds around set_parents() only, and add a regression
test that is compiled with -O3 -Werror=array-bounds on GCC.

Fixes #5742

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

* Fix the false -Warray-bounds error by setting the type after the value

The pragma around set_parents() is no longer needed: the base branch
(#5585) creates a value before setting its type. Before, the type of a new
string was stored first, so GCC had to assume that operator new could
change it again, kept the object branch of the inlined set_parents() alive,
and checked it against the string's allocation. Rewriting set_parents()
itself (if/else instead of switch) does not help.

Verified with Docker GCC 12.5, 13, 14, 15.3 and 16.2: the regression test
builds and passes without the pragma, and fails to build on develop.

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

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Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-02 11:24:10 +02:00
..
2026-09-27 16:56:21 +02:00