cmake/clang_flags.cmake claimed -Wno-unsafe-buffer-usage was needed only
for Doctest and that -Wno-missing-noreturn had "no way to silence...
otherwise" (PR #4871, which never actually attempted a source fix).
Neither held up under investigation (todo 130):
- -Wno-unsafe-buffer-usage is pervasive (208 distinct sites across 19
files measured with clang trunk in silkeh/clang:dev), spanning the
library's own low-level numeric/buffer code (to_chars, serializer,
lexer, binary reader/writer, input adapters, json_pointer) as well as
vendored Doctest itself (96 of the 208 sites). A source-level fix is
not feasible at this scale; the comment now says so instead of
blaming Doctest alone.
- -Wno-missing-noreturn had exactly two real trigger sites, both
genuinely and unconditionally non-returning: a test-only throwing
allocator (tests/src/unit-allocator.cpp) and, previously undiscovered,
wide_string_input_adapter::get_elements<T>() in
include/nlohmann/detail/input/input_adapters.hpp. Verified this isn't
a wider pattern by checking all 160 JSON_THROW call sites in the
library for functions whose entire body is an unconditional throw.
Annotated both ([[noreturn]] in the test file, since JSON_HEDLEY_NO_RETURN
is #undef'd by the time test code runs; JSON_HEDLEY_NO_RETURN in the
library file, its first real use anywhere in the codebase) and
dropped the suppression entirely.
single_include/nlohmann/json.hpp regenerated via `make amalgamate`;
`make check-amalgamation` passes.
Verified in Docker (silkeh/clang:dev, matching the ci_static_analysis_clang
CI job): baseline builds clean, and the full 194-target test suite builds
with zero warnings under the corrected CLANG_CXXFLAGS (-Wno-missing-noreturn
no longer in the list). Also sanity-compiled and ran unit-allocator.cpp and
unit-wstring.cpp on host Apple Clang to confirm behavior is unchanged.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann