On Tue, Jun 9, 2020 at 9:02 AM Luya Tshimbalanga <luya@fedoraproject.org> wrote:
Hello team,

Latest release of ispc failed to build due gcc=c++ related errors as
seen on scratch build:
https://koji.fedoraproject.org/koji/taskinfo?taskID=45567484

Here is the source located on https://src.fedoraproject.org/rpms/ispc/

Patch welcome to fix the issue.

Hi Luya,

The build failed with:
/builddir/build/BUILD/ispc-1.13.0/src/bitcode_lib.cpp: In member function 'void BitcodeLib::print() const':
/builddir/build/BUILD/ispc-1.13.0/src/bitcode_lib.cpp:61:17: error: variable 'type' set but not used [-Werror=unused-but-set-variable]
   61 |     const char *type = nullptr;
      |                 ^~~~ 
cc1plus: all warnings being treated as errors

This means that the compiler found a tiny warning (unused variable) but treated it as an error because -Werror was set during the build.

What I would suggest doing is looking into how to disable -Werror (it could be a configure flag) or perhaps just patch it out for Fedora builds. -Werror makes a lot of sense for upstream where they want to make sure their build is warning free, but not for a distribution such as Fedora where we introduce new changes all the time (each compiler adds new, different warnings) and it's completely impractical to have -Werror turned on for our builds.

Hope this helps,
Kalev