gh-129467: turn off false-positive -Wstringop-overflow in word_to_string()

[skirpichev]

• Issue: New warning on main: writing 1 byte into a region of size 0 [-Wstringop-overflow=] #129467

[skirpichev]

@skrah, could you take look on this variant of solving #108562? Attempt to enable -fstrict=overflow was unsuccessful, unfortunately.

[skirpichev]

@vstinner, maybe you could review this little pr? Note, that 4.0.0 has more diagnostic ignored (at top of the file):

#if defined(__GNUC__) && !defined(__INTEL_COMPILER) &&__GNUC__ >= 7#pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
#pragma GCC diagnostic ignored "-Wmisleading-indentation"
#pragma GCC diagnostic ignored "-Warray-bounds"
#endif

I turn of one diagnostic and more locally (with following pop directive).

Another option (mentioned in the issue) - update bundled copy.

[vstinner]

Modules/_decimal/libmpdec/io.c

libmpdec/ is vendored copy of a 3rd party project. You should fix the issue in the upstream first. Otherwise, it will be lost at the next update.

See upstream: https://www.bytereef.org/mpdecimal/.

[skirpichev]

Ok, then I close pr and issue.

Unfortunately, @skrah blocked in python's repos. But he is aware about issue anyway.

[vstinner]

Merged, thank you.