Unable to create Fedora releases due to compilation error

[SeanTAllen]

Fedora COPR builds changed the warnings they have on or otherwise changed the gcc version and ponyc no longer compiles. We need to fix this to get COPR builds working again.

See: https://copr-be.cloud.fedoraproject.org/results/ponylang/ponylang/fedora-29-x86_64/01042125-ponyc/build.log.

What we need to do:

• investigate gcc version and flag used
• setup/modify existing ci to match (not sure which is most applicable)
• fix the issue

the 2nd 2 steps should be part of the same PR.

[SeanTAllen]

I think gcc 8.1 along with the -Werror=stringop-truncation flag should be enough to trigger this.

[SeanTAllen]

It's unclear to me whether this is a real bug or not (the compiler thinks it is). I assume from a quick glance that it is, but we'd need to verify that.

[SeanTAllen]

@jemc i'm not familiar with what is going on with the AST. Is this an actual error?

[jemc]

I get a 404 error when I click the link to see the build log. Do you have a copy of the error location and message?

[SeanTAllen]

Ugh. Apparently the build log gets deleted after a week. It's gone.

Building with gcc 8.1 should do the trick. There's a warning about strncpy at 3 locations in verify.c.

The warning to use to see it is: "-Werror=stringop-truncation"

[stronny]

I have this error on gcc (Debian 8.3.0-6) 8.3.0 i686:

src/libponyc/pass/refer.c: In function ‘generate_multi_dot_name’:
src/libponyc/pass/refer.c:154:3: error: ‘strncpy’ output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation]
   strncpy(buf + offset, name, slen);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/libponyc/pass/refer.c:153:17: note: length computed here
   size_t slen = strlen(name);
                 ^~~~~~~~~~~~
src/libponyc/pass/refer.c:165:5: error: ‘strncpy’ output truncated before terminating nul copying as many bytes from a string as its length [-Werror=stringop-truncation]
     strncpy(buf + offset, name, slen);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/libponyc/pass/refer.c:164:12: note: length computed here
     slen = strlen(name);
            ^~~~~~~~~~~~
cc1: all warnings being treated as errors
make: *** [Makefile:925: build/release/obj-native/libponyc/pass/refer.o] Error 1

[SeanTAllen]

An option to fix for now would be:

-Wno-stringop-truncation on Makefile line 134.

It doesn't verify if the warning is real or not (this need to look at that, but it should in theory, put gcc 8+ compilation on the same footing as all the others in that it will build.

[SeanTAllen]

N.B. its quite possible that some of these are false positives.

[SeanTAllen]

Yeah, these look like false positives.

[SeanTAllen]

Using Ubuntu Xenial and Gcc 8.3, I am unable to reproduce this. Very odd.