Bazel coverage not working on java_tests

[ThomasCJY]

Description of the problem / feature request:

bazel coverage will generate empty report of coverage_report.dat file and the test coverage feature is not working correctly.

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

I created a test repository and it can be easily reproduced by running bazel coverage command

What operating system are you running Bazel on?

Linux Ubuntu 20.04

What's the output of bazel info release?

release 4.0.0

Have you found anything relevant by searching the web?

no

[nkoroste]

could be related to: #5426

[ulfjack]

The problem is that Bazel uses an automatically computed default for --instrumentation_filter, which is

INFO: Using default value for --instrumentation_filter: "^//src/main/java/com/example/unit[/:]".

However, the JavaUtil.java file is in src/main/java/com/example/JavaUtil.java and therefore doesn't match the filter.

[comius]

@c-mita can you triage this?

[github-actions]

Thank you for contributing to the Bazel repository! This issue has been marked as stale since it has not had any activity in the last 1+ years. It will be closed in the next 90 days unless any other activity occurs. If you think this issue is still relevant and should stay open, please post any comment here and the issue will no longer be marked as stale.

[c-mita]

As pointed out, the issue appeared to be the inappropriate instrumentation filter.