x/tools/gopls: support renaming a package

[chiawendt]

What did you do?

1. Open a go file in vscode
2. Put keyboard cursor on the line package somepackage.
3. Press F2 (rename symbol)

What did you expect to see?

Let me rename package.

What did you see instead?

This element cannot be renamed.

Build info

golang.org/x/tools/gopls v0.5.0
go version go1.15 linux/amd64

[mattheusv]

There is some tips to implement this? I think that this could be super useful and I would like to implements. I think that the implementation should be in qualifiedObjsAtProtocolPos function, I'm in the right way?

[stamblerre]

@msAlcantara: Thanks for your interest! I think this is slightly more complicated than that because the package name declaration does not have a types.Object, so I don't think it would work in the framework of qualifiedObjsAtProtocolPos. Still, renaming a package should be a lot simpler than a standard rename, because you can access the position of the package name by looking at the AST of each file in the package (https://pkg.go.dev/go/ast#File.Package). There will be some complexity with test packages, but hopefully it's as simple as updating their names too. Does that help at all?

[mattheusv]

Thanks very much for your awnser, but I have some question about it.

1. There something that tell me that the rename is of package name?
2. Do you think that is better change qualifiedObjsAtProtocolPos to support rename a package or is better do something like this: if isPackageRename(...) { ... }?

Sorry is this questions is too dump, I'm a just getting started with gopls source code and I'm trying to understand

[stamblerre]

Please don't apologize--this is a tricky issue! I think the easiest thing would be to do something like if isPackageRename(...) in the rename logic itself (not in qualifiedObjsAtProtocolPos).

[jan-xyz]

Should an implementation for this also rename the directory and the package comment? And if "yes", is this still possible by looking at the position in the AST? What would happen if the package declaration and directory are already different? Should they become harmonised or only rename the package declaration in that case? We probably also need to account for blackbox test packages, right (e.g. package foo_test)?

[findleyr]

Hi I think this is something that @dle8 might look into.

Should an implementation for this also rename the directory and the package comment?

IMO yes it should do both (note that LSP supports renaming files via TextDocumentEdits, so I think this should be possible).

To start we can implement textDocument/references on package names (package foo).