So spawns can read content of directires within action exuection.

Part of #16556.

PiperOrigin-RevId: 486918859
Change-Id: Ida86e4c927093d26f7f96d2f0c2aa0d1d74cc8a4

…#16738)

So spawns can read content of directires within action exuection.

Part of #16556.

PiperOrigin-RevId: 486918859
Change-Id: Ida86e4c927093d26f7f96d2f0c2aa0d1d74cc8a4

Co-authored-by: Googler <chiwang@google.com>

This PR solves the problem in a different way that bazelbuild#16475 tries to solve:

1. bazelbuild#16812 allows skyframe read metadata from ActionFS.
2. Use `ActionFileSystem` to check existence of coverage data.
3. Fire event `CoverageReport` in the action after the coverage report is generated and listen to it in `ToplevelArtifactsDownloader` to download the report.

Closes bazelbuild#16556.

PiperOrigin-RevId: 502854552
Change-Id: I2796baaa962857831ff161423be6dffa6eb73e5c

* Returns null if filesystem of test outputs is not ActionFS when processing test attempt event.

Previously, we assert that the filesystem of test outputs is ActionFS when we are processing test attempt event. However this is not true when the test hits action cache.

This CL looses the check to return null.

PiperOrigin-RevId: 501023752
Change-Id: I17cbb26e0a2b5fd30cb781818e42172ac672919e

* Make `bazel coverage` work with minimal mode

This PR solves the problem in a different way that #16475 tries to solve:

1. #16812 allows skyframe read metadata from ActionFS.
2. Use `ActionFileSystem` to check existence of coverage data.
3. Fire event `CoverageReport` in the action after the coverage report is generated and listen to it in `ToplevelArtifactsDownloader` to download the report.

Closes #16556.

PiperOrigin-RevId: 502854552
Change-Id: I2796baaa962857831ff161423be6dffa6eb73e5c

---------

Co-authored-by: kshyanashree <109167932+kshyanashree@users.noreply.github.com>

This PR solves the problem in a different way that #16475 tries to solve:

1. #16812 allows skyframe read metadata from ActionFS.
2. Use `ActionFileSystem` to check existence of coverage data.
3. Fire event `CoverageReport` in the action after the coverage report is generated and listen to it in `ToplevelArtifactsDownloader` to download the report.

Closes #16556.

PiperOrigin-RevId: 502854552
Change-Id: I2796baaa962857831ff161423be6dffa6eb73e5c

Adds the new `test/shell/test_coverage_helper.sh` file, which defines
(amongst other helpers) `COVERAGE_FLAGS` as containing:

- `--experimental_fetch_all_coverage_outputs`
- `--experimental_split_coverage_postprocessing`

This resolves the following error under Bazel 7.4.1 with Bzlmod enabled:

```txt
/mnt/engflow/worker/work/3/exec/bazel-out/
darwin_arm64-opt-exec-ST-f4dfef26580e/bin/external/
bazel_tools~remote_coverage_tools_extension~remote_coverage_tools/Main:
  Cannot locate runfiles directory.
  (Set $JAVA_RUNFILES to inhibit searching.)
```

This error resembles bazelbuild/bazel#20577,
but wasn't due to the presence of `--nobuild_runfile_links`, but to the
lack of the aforementioned `--experimental_*` flags. I learned about
these flags from:

- bazelbuild/bazel#4685 (comment)
- bazelbuild/bazel#16556