Comment-only code blocks are removed when OrderedImports is enabled

[a7medev]

Problem

swift-format (with OrderedImports enabled) turns the following code

import A

// Comment

import B

into this

import A
import B

Removing the comment in between.

Expected Behavior

I expect it to output the following code preserving the comment.

import A
import B

// Comment

Potential Solution

After looking into this issue, it happens in convertToCodeBlockItems(lines:) where the comment is added pendingLeadingTrivia but never added to the final output.

One way to fix this is to append the remaining pendingLeadingTrivia to the last item's trailingTrivia (probably trimming lines surrounding comments as well).

[kkebo]

If that comment is for import B, shouldn't it come before import B?

import A
// Comment
import B

[a7medev]

@kkebo In the provided code, // Comment is separated from import B by an extra newline so it's not associated with the import.

But maybe moving the comment after import statements isn't a good solution. I can see cases where such behavior can be frustrating.

[kkebo]

@a7medev I don't think those two are always separated. Please see the following real example.

https://github.com/swiftlang/swift-platform-executors/blob/412b211c820431fbc8a8c78e2bb8e14e3fcb96c0/Package.swift#L4-L5

[a7medev]

@kkebo This is a different case.

In the following scenario, // Comment is separated from import B by a single newline, the comment is indeed associated with the import and should move with it.

// Comment
import B

I'm describing a different scenario where there are two newlines between the comment and the import.

// Comment

import B

In this case, swift-format treats // Comment as a separate code block that's not associated with the import.