Detected instability when built `flatbuffers-2.0.0` on `gcc-12`:
[ 75%] Building CXX object CMakeFiles/flattests.dir/tests/test_builder.cpp.o
.../c++/12.0.0/bits/shared_ptr_base.h:397:45: error: 'size' may be used uninitialized [-Werror=maybe-uninitialized]
397 | explicit _Sp_ebo_helper(_Tp&& __tp) : _M_tp(std::move(__tp)) { }
| ^~~~~~~~~~~~~~~~~~~~~~
In file included from flatbuffers/tests/test_builder.cpp:1:
flatbuffers/tests/test_builder.h: In function 'void builder_move_assign_after_releaseraw_test(Builder) [with Builder = flatbuffers::FlatBufferBuilder]':
flatbuffers/tests/test_builder.h:63:10: note: 'size' was declared here
63 | size_t size, offset;
| ^~~~
...
In file included from flatbuffers/tests/test_builder.cpp:1:
flatbuffers/tests/test_builder.h: In function 'void builder_move_assign_after_releaseraw_test(Builder) [with Builder = GrpcLikeMessageBuilder]':
flatbuffers/tests/test_builder.h:63:10: note: 'size' was declared here
63 | size_t size, offset;
| ^~~~
cc1plus: all warnings being treated as errors
Here is the relevant bit of test:
template<class Builder>
void builder_move_assign_after_releaseraw_test(Builder b1) {
auto root_offset1 = populate1(b1);
b1.Finish(root_offset1);
size_t size, offset;
std::shared_ptr<uint8_t> raw(
b1.ReleaseRaw(size, offset), [size](uint8_t *ptr) {
flatbuffers::DefaultAllocator::dealloc(ptr, size);
});
Note how `b1.ReleaseRaw(size, offset)` is expected to populate `size`
and `[size](uint8_t *ptr) {` captures the result. But both are parameters
to the same function call and thus evaluation order is unspecified.
85b4effac6