rules_go broken by Bazel@HEAD because docker env

[hlopko]

Hello go team :)

CC @philwo

It seems that this PR bazelbuild/bazel#5721 will break //tests/core/go_path:go_path_test once released. I can cleanly reproduce, buildkite can as well (https://buildkite.com/bazel/bazel-with-downstream-projects-bazel/builds/386#61d56139-a891-4868-b136-e34a6f3f68f3).

Would you mind taking a look, and in case this actually is a bug in Bazel file an issue?

Thank you!

[jayconrod]

I'll take a look at this today. Any special steps to reproduce?

Just from a quick look at the logs, it seems that we're getting a symlink but we expect a regular file. This would be inside a directory output; my understanding is that the action that produces the directory has control over the file content and metadata within it. Is that changing?

What's the story with the docker env?

[jayconrod]

@mhlopko I've reproduced this. There's an observable change in Bazel behavior. Not sure if it's a bug or an intentional difference.

Here's a minimal gist that reproduces the problem. In this gist, a Skylark rule declares a directory output and executes a script that populates it with two files: an empty regular file, and a symlink to that file. A separate test checks that the file is a regular file, but it's actually a symlink now.

The go_path rule is a fancier version of this. It creates a directory of source files, and it allows users to specify a mode which may be "copy", "link", or "archive". With this change in behavior, I don't think it will be possible to implement the "copy" mode. That said, I don't expect this will break tools that use go_path, but it's hard to be sure.

[jayconrod]

Closing the issue here because I think this is a regression in Bazel. Opened bazelbuild/bazel#5971 to track this.