cmd/cue: fmt -s does not preserve the scope of comments which is important for tool files

[gotwarlost]

What version of CUE are you using (cue version)?

$ cue version
cue version v0.6.0

go version go1.20.7
      -buildmode exe
       -compiler gc
       -trimpath true
     CGO_ENABLED 1
          GOARCH arm64
            GOOS darwin

Does this issue reproduce with the latest stable release?

Yes.

What did you do?

Wrote a tool file and ran cue fmt -s on it. While the output of the formatting is correct, it changes the behavior of the tool file by changing the scope of the comment attached to the command.

$ cat make_tool.cue
package make_tool

import (
	"tool/exec"
)

// displays help for available commands
command: help: {
	show: exec.Run & {cmd: [ "sh", "-c", "cue help cmd | grep -A2 'Available Commands:'"]}
}

$ cue cmd help
Available Commands:
  help        displays help for available commands

$ cue fmt -s make_tool.cue

# note that the help text is gone
$ cue cmd help
Available Commands:
  help

# that's because the comment is now scoped to command: help: show instead of command: help
$ cat make_tool.cue
package make_tool

import (
	"tool/exec"
)

// displays help for available commands
command: help: show: exec.Run & {cmd: [ "sh", "-c", "cue help cmd | grep -A2 'Available Commands:'"]}

What did you expect to see?

No change to the behavior of the cue cmd help output after simplification

What did you see instead?

The help text disappears because of the scope change of the comment

[mvdan]

Thanks for the report - agreed that cue fmt, even with the -s flag, should not lead to changes in the output of cue cmd help.