Setting `--output_base` in the home `.bazelrc` causes rules_bazel_integration_test tests to deadlock

[sitaktif]

Currently, setup-bazel set the bazel output base (/home/runner/.bazel by default) in the home .bazelrc (/home/runner/.bazelrc).

This is causing deadlocks when using rules_bazel_integration_tests:

• the initial invocation uses /home/runner/.bazel as its output base, taking the lock on this location.
• a bazel integration test runs another bazel invocation as part of its test case. It processes the home .bazelrc and also settles on /home/runner/.bazel as its output base. This inner invocation tries to kill the existing bazel server using that location but deadlocks doing so.

Example of logs when the inner bazel invocation is run with --client_debug:

$TEST_TMPDIR defined: output root default is '/home/runner/.bazel/execroot/_main/_tmp/2dbce8196efc9d097018b00a08eb66fa' and max_idle_secs default is '15'.
[INFO src/main/cpp/option_processor.cc:407]] Looking for the following rc files: /etc/bazel.bazelrc,/home/runner/.bazel/execroot/_main/bazel-out/k8-fastbuild/bin/tests/integration_tests/my_integration_test.runfiles/_main/tests/integration_tests/example_workspaces/my_integ_test_workspace/.bazelrc,/home/runner/.bazelrc
[INFO src/main/cpp/rc_file.cc:56]] Parsing the RcFile /home/runner/.bazel/execroot/_main/bazel-out/k8-fastbuild/bin/tests/integration_tests/my_integration_test.runfiles/_main/tests/integration_tests/example_workspaces/my_integ_test_workspace/.bazelrc
[INFO src/main/cpp/rc_file.cc:56]] Parsing the RcFile /home/runner/.bazelrc
[INFO src/main/cpp/blaze.cc:1509]] Debug logging requested, sending all client log statements to stderr
[INFO src/main/cpp/blaze.cc:1385]] Acquired the client lock, waited 0 milliseconds
[USER src/main/cpp/archive_utils.cc:227]] Extracting Bazel installation...
[7 / 8] Testing //tests/integration_tests:my_integration_test; 0s local
[INFO src/main/cpp/blaze.cc:1585]] Trying to connect to server (timeout: 30 secs)...
[INFO src/main/cpp/blaze.cc:996]] Killing running server because it is using another version of Bazel
[INFO src/main/cpp/blaze.cc:1756]] Shutting running server with RPC request
<deadlocks here>

Workarounds are always trivial because the home bazelrc has a relatively high precedence (it has higher precedence than the workspace .bazelrc, cf. https://bazel.build/run/bazelrc). Moreover, the --output_base option cannot be unset once it's been set.

Overall, I wonder if using the home bazelrc for this is an anti-pattern? Each bazel workspace is expected to use a different output base, and although many repositories only build a single Bazel workspace, some build multiple ones. I do appreciate there is a practical element to doing it this way, though.