x/tools/gopls: code action for “add field names to struct literal”

[bcmills]

gopls version
golang.org/x/tools/gopls v0.6.0
    golang.org/x/tools/[email protected] h1:i+eJsCS+4N+3YSxLbuq0SrfWim3V8eG4WgdK8xQdzwI=

What did you do?

1. In an emacs buffer, open $GOROOT/src/html/template/template.go:229:
   

   go/src/html/template/template.go

   Lines 228 to 233 in f1980ef

   	ret := &Template{
   	nil,
   	text,
   	text.Tree,
   	t.nameSpace,
   	}

2. M-x eglot-code-actions

What did you expect to see?

An LSP code action that can add field names to the Go struct literal at the current location.

(@stamblerre informs me that VSCode currently provides this functionality using gomodifytags; cc @fatih.)

What did you see instead?

[eglot] No code actions here

[fatih]

What is the expected output for the assignment on line template.go/229 ? I'm not sure how we can add tags here (but maybe I'm missing something). For the record, here are some examples that we support recently: https://github.com/fatih/gomodifytags/releases/tag/v1.13.0

[hyangah]

Based on the title, it sounds like the feature is about transformation to use named fields instead of positional args for struct literals. gomodifytags is to add structure tags, so unrelated.

[bcmills]

Yes, @hyangah has the right intent.

I want the code action to transform the code from

	 ret := &Template{ 
	 	nil, 
	 	text, 
	 	text.Tree, 
	 	t.nameSpace, 
	 } 

to

	 ret := &Template{ 
	 	escapeErr: nil, 
	 	text:      text, 
	 	Tree:      text.Tree, 
	 	nameSpace: t.nameSpace, 
	 } 

[fatih]

Aha I see, thanks for the clarification. I think keyify does this for you (it also has an emacs plugin). In vim-go you can use :GoKeyify

https://github.com/dominikh/go-tools/tree/master/cmd/keyify

[dominikh]

Integrating keyify with gopls is on my todo list. At the same time, gopls already has fillstruct, and I wouldn't be surprised if most of the code required for keyify and fillstruct is identical.

[Frederick888]

It seems that it's not easy to get keyify to work with Go modules these days: dominikh/go-tools#834

And although golang/vscode-go#1631 has been resolved, which seems to have made omitting field names a better option, I think having field names still has its advantages:

• Easier when adding/removing fields. Especially helpful in tests where test structs often have consecutive fields of the same type
• Still in tests, sometimes we write a bunch of new tests that have field names and now we'd like to add field names to the existing ones
• As a neovim user I'm still waiting for anticonceal (virtual text occupying horizontal space) neovim/neovim#9496

So it'd be great if gopls can offer this functionality.

[dnwe]

This capability has been available since [email protected] and works in neovim lsp too

[dnwe]

This issue can probably be closed as a dupe of #53062 which has the attached PR that was merged in v0.9.0 to support this capability

[mvdan]

Thank you for spotting that, @dnwe!

[Frederick888]

@dnwe Looks like this only works if the struct is in a different package?

No code actions on Bar (or govet warning)

Foo on the other hand:

Our test matrices usually involve some (anonymous) structs in the same package. Any way to make this case work? Ty