_collect_cc_coverage script can silently fail to produce coverage #18650
Description
Description of the bug:
I noticed an issue where rules_rust rules were failing to produce coverage reports when running with --experimental_split_coverage_postprocessing and found it to be caused by runfiles not being available to the llvm-cov call which expects test binaries to be available:
https://github.com/bazelbuild/bazel/blob/6.2.1/tools/test/collect_cc_coverage.sh#L95-L97
The script would fail with a File not found error and no coverage would be reported.
This to me seems like a miss. I can see a test not having any coverage to report if maybe there's no dependencies and --instrument_test_target is not set, but otherwise I fully expected bazel coverage invocations to fail if a genuine error occurs.
What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.
Run bazel coverage //... --experimental_split_coverage_postprocessing in rules_rust v0.22.0 on Bazel v6.2.1.
Which operating system are you running Bazel on?
Linux, MacOS
What is the output of bazel info release?
release 6.2.1
If bazel info release returns development version or (@non-git), tell us how you built Bazel.
No response
What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?
No response
Is this a regression? If yes, please try to identify the Bazel commit where the bug was introduced.
No response
Have you found anything relevant by searching the web?
https://bazelbuild.slack.com/archives/CA31HN1T3/p1686230133034699 is the thread where this issue was triaged.
Any other information, logs, or outputs that you want to share?
No response