Clang compatibility issue

[Dirkson]

Experienced behavior

When being built as a standalone project using clang, somehow both -Wall and -Wunused fail to convert a clang warning into an error.

The warning in question is: ../src/graphene-matrix.c:1594:1: warning: unused function 'graphene_matrix_transpose_transform_vec4' [-Wunused-function]

This warning DOES occur when travisCI is run: https://travis-ci.org/ebassi/graphene/jobs/548740495

Also, that particular travisCI job says the clang version is both 3.8 and 5.0, which seems weird.

When graphene is instead built as a subproject using clang, this warning IS converted to an error, and as a result graphene cannot be used as a a subproject in another project.

I'm not at all sure this isn't a meson or clang issue, but your knowledge of meson build files is better than mine, so I figure opening an issue with you is a good next step.

Expected behavior

The warning should always convert into an error, failing the travisCI build and forcing the removal of the warning through clever source code wizardry.

Steps to reproduce

Your travisCI build is already reproducing this issue consistently.

Operating system in use

Void linux for mine. Unsure what travis uses. Magic probably.

Cheers,
-Dirk

[Emmanuele Bassi]

Thanks for the detailed issue! Much appreciated.

Also, that particular travisCI job says the clang version is both 3.8 and 5.0, which seems weird.

Clang 5.0 is the backported version shipped by the base Ubuntu CI runner; 3.8 is the version of Clang in the Docker image I use to run the job, and it's coming from Debian Stretch.