Go comments not being cleaned up correctly

[conormurray95]

Issue
When running the tool with cleanup_comments = true against a go codebase I'm seeing some inconsistent behaviour around comment cleanup.

Steps to reproduce
I've added test cases demonstrating this issue in this pr #375

Observations:

• Multiline comments are cleaned up
• Single line comments are not cleaned up
• Single line comments are cleaned up provided the next node above is also a comment

The test cases provided in the pr are for cleaning up if blocks however I've noticed the same behaviour when cleaning up constants in my own codebase e.g.

Before

const (
    // comment
    myFlag = "flag"

   // stale comment
   myStaleFlag = "stale flag"
)

After

const (
    // comment
    myFlag = "flag"

   // stale comment
)

Expected

const (
    // comment
    myFlag = "flag"
)

The constants example above exhibits the same behaviour around only cleaning up comments if they're (a) multiline or (b) have another comment node directly above them.

Any context on if this is a known issue in other languages or seems go specific etc would be great. It's the one piece left stopping autogenerated pr's we have being able to be directly merged.

[ketkarameya]

Hey! Thanks a lot for reporting this.
the go cleanup mechanism we have is pretty much experimental :| We have not battle tested it yet (by running it on our internal codebase) But thanks for doing this :) I will look into it. Like our java/kotlin cleanup is kinda robust.
cc @dvmarcilio

[dvmarcilio]

thanks for pinging me, @ketkarameya.

Thanks for the detailed report, @conormurray95!
It nicely outlines the comments-cleanup inconsistencies I saw when experimenting with the Go rules.

I'll try to look closer into this in the upcoming days. Hopefully, I can pinpoint a cause.

[ketkarameya]

@conormurray95 can you check this branch go_comment_bug #392 on your go codebase, and let me know if it works as expected?

[conormurray95]

Hey @ketkarameya apologies I just got a chance to look back at this, that pr looks good and solves the cases I'd spotted. Thanks!