Bazel does not read /etc/bazelrc

[guibou]

Describe the bug

By default and according to bazel documentation (https://docs.bazel.build/versions/master/guide.html#where-are-the-bazelrc-files), bazel is looking for a system-wide configuration is /etc/bazel.bazelrc.

In ba327a5 I decided to override this path and make it point in $out/etc/bazelrc. It was the easiest solution to pass arguments to bazel in order to fix a few runtime issues.

However it breaks the assumption that user can configure bazel using /etc/bazel.bazelrc.

To Reproduce

• Use bazel from nixpkgs with nix run nixpkgs.bazel.
• Set some bazel settings in your /etc/bazel.bazelrc file
• Observe that bazel ignores this file

Expected behavior

I'm opening this bug report to discuss what should be the expected behavior here? Should we respect the /etc/bazel.bazelrc? If yes, I'll open a pull request to restore the previous behavior.

[flokli]

I'll be in favour of keeping support for all paths specified in the documentation - having a system-wide /etc/bazel.bazelrc is something people might want to make use of, so we shouldn't take away that possibility.

We currently set the following options in bazelrc:

      build --distdir=${distDir}
      fetch --distdir=${distDir}
      build --copt="$(echo $NIX_CFLAGS_COMPILE | sed -e 's/ /" --copt="/g')"
      build --host_copt="$(echo $NIX_CFLAGS_COMPILE | sed -e 's/ /" --host_copt="/g')"
      build --linkopt="-Wl,$(echo $NIX_LDFLAGS | sed -e 's/ /" --linkopt="-Wl,/g')"
      build --host_linkopt="-Wl,$(echo $NIX_LDFLAGS | sed -e 's/ /" --host_linkopt="-Wl,/g')"
      build --host_javabase='@local_jdk//:jdk'
      build --host_java_toolchain='${javaToolchain}'

We should either patch these as defaults into nixos, or introduce reading from a distro-provided location (should be coordinated with bazel upstream).

I think adding a wrapper is a bit too much for all these options.

[guibou]

@flokli I do agree with your point of view. I'll try to propose a PR which restore the old behavior. In the meantime, I'm open to other comments on this issue.

Regarding the options you quote, they are used in a local .bazelrc during build only. The global bazelrc that I provide is way simpler:

build --override_repository=remote_java_tools_linux=/nix/store/syddjzd8w2vxh5ip2d01p5sf0gscr0gp-remote_java_tools_linux
build --distdir=/nix/store/xxz8rjkxs7ravd8zg8fm4qdrwdvxyxql-bazel-deps

Both were ad hoc solution for different problems, respectively issue #63096 and commit 67904dc.