[Feature] go.mod FilePath ReplaceDirective Support

[stefanpenner]

PR Description

What type of PR is this?

Feature

What package or component does this PR mostly affect?
language/go

What does this PR do? Why is it needed?

This builds on the go.work support PR and the new rctx.watch_files support to add support for FilePath ReplaceDirective, in go.mod and go.work files when using bzlmod go_deps extension.

For example, now the following native go capability works in the bazel world:

module github.com/bazelbuild/bazel-gazelle/tests/bcr/go_mod

go 1.21

require (
	example.org/hello v1.0.0
        // ... snip ...
)

// ... snip ...

replace example.org/hello => ../../../fixtures/hello

Which issues(s) does this PR fix?

Fixes #1775

Status

• make it "work"
• ensure relative and absolute pathing works
  • /Users/user/path/to/mod
  • ../../path/to/mod
• test with nightly bazel + rctx.watch_files and verify it fixes "rebuilds"
• expand bcr tests
  • go.mod
  • go.work
• even less hack and even more quality
• fix tests that fail on the bazelbuild/bazel-gazelle CI

[fmeum]

@stefanpenner Could you extract the parts of the Go code changes that are essentially a pure refactoring (e.g. extracting out functions)? We could merge those right away and simplify the overall diff.

[fmeum]

The overall approach looks good to me. Kudos to @Wyverald for giving us the required API.

[stefanpenner]

@stefanpenner Could you extract the parts of the Go code changes that are essentially a pure refactoring (e.g. extracting out functions)? We could merge those right away and simplify the overall diff.

@fmeum sure, let me get that started

[stefanpenner]

@fmeum Extracted PR -> #1780. I'm a little stretched for time, so once that lands I'll rebase this one so it incorporates those changes.

[stefanpenner]

@fmeum Extracted PR -> #1780. I'm a little stretched for time, so once that lands I'll rebase this one so it incorporates those changes.

Now that #1780 has landed, I've propagated the change through #1731 and this PR. Once #1731 lands, I'll do the same again here which should cleanup the diff considerably.

[stefanpenner]

@fmeum thanks for the review, I've updated & rebased the PR. I left one discussion point for us, but from my vantage point we are looking pretty good. Let me know if there is anything else I can dig into to help move this forward.

[stefanpenner]

@fmeum thanks for the review, I've made the updates. Feel free to take another look, and let me know if anything else needs attention.

[fmeum]

Thanks for the contribution!

@tyler-french @linzhp Do you have any concerns or comments? I guess that this feature won't really be used at Uber, so testing it there may not be that helpful.

[linzhp]

yeah, we don't use go.work, although we do use replace in go.mod. So no concerns