x/tools/gopls: handle replace directives

[stamblerre]

We watch all of the files in the module root for changes on-disk, and we also use changes to the current module as a heuristic for when it's necessary to rescan for imports. We should also track replace directives and watch file changes in replace targets.

[stamblerre]

Fixed as of CL 239198, though VS Code does not support watching directories outside of the workspace root.

[kevlar700]

Fixed as of CL 239198, though VS Code does not support watching directories outside of the workspace root.

Is this fixable, otherwise it seems to me that this means extending modules via the filesystem and package main is a better solution than replace and named modules? Not reliable on Windows unfortunately but workable on Unix systems.

I guess the other option is unworkable (putting all projects in one module) as in my experience, a library change might make build errors unhelpful and will be a pain with so many files in scope.

Edit: Actually replaced libs outside vscodes root, seems to work today, if you disable gopls.

Arrgh still has some issues with build tags then.

[stamblerre]

The title of this issue is a bit misleading--specifically, the issue is that on-disk changes to replaced modules will not be reflected to the editor because of limitations to VS Code's file watching API. gopls should still generally work with replaced modules. @kevlar700: If you are having an issue with the VS Code Go extension, please take a look at the Troubleshooting guide and file a new issue.