Remote: Support the case where output files are under an output direc…

[coeuvre]

…tory and are omitted from ActionResult.

• Handle another case when outputs are under output directory.
• Fix unit test and one more.
• Add integration test
• Update RemoteWorker to handle this case.

Supplement for #15329.

[jmillikin]

I might be misunderstanding, but according to the Remote Execution API protobuf at https://github.com/bazelbuild/remote-apis/blob/main/build/bazel/remote/execution/v2/remote_execution.proto, the ActionResult you describe is an error. If a command has an output file under an output directory, the executor should return an ActionResult containing entries for both.

  // The output files of the action. For each output file requested in the
  // `output_files` or `output_paths` field of the Action, if the corresponding
  // file existed after the action completed, a single entry will be present
  // either in this field, or the `output_file_symlinks` field if the file was
  // a symbolic link to another file (`output_symlinks` field after v2.1).
  // [...]
  repeated OutputFile output_files = 2;

[coeuvre]

Technically, yes, executor should include declared output files inside the ActionResult. But there are implementations omit them when I was testing your PR. I am not sure whether they omit them on purpose or is just a bug. I think it wouldn't hurt if Bazel can detect this and continue the build.

[coeuvre]

Closing as this PR is out of date and I don't have the workload to move it forward.