[clang-tidy] Warnings from headers should be on by default

[carlosgalvezp]

Currently, users must opt-in to getting warnings from headers, via the unintuitive syntax --header-filter=<something>. This is most likely not what people want, and is inconsistent with e.g. the clang compiler.

Instead, clang-tidy should warn on all non-system headers by default, and --header-filter should then be used to narrow down which subset of headers to warn on, if wanted.

The solution to this problem would be to simply make header-filter default to .* instead of an empty string.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Carlos Galvez (carlosgalvezp)

Currently, users must opt-in to getting warnings from headers, via the unintuitive syntax `--header-filter=<something>`. This is most likely not what people want, and is inconsistent with e.g. the clang compiler.

Instead, clang-tidy should warn on all non-system headers by default, and --header-filter should then be used to narrow down which subset of headers to warn on, if wanted.

The solution to this problem would be to simply make header-filter default to .* instead of an empty string.

[vbvictor]

+1 on this. I actually didn't fix on clang-tidy's header files because of this... need to do it in the foreseeable future