[SR-2188] Xcode closure auto-indentation is hard to read with some styles

[swift-ci]

Previous ID	SR-2188
Radar	None
Original Reporter	bnut (JIRA User)
Type	Bug

Additional Detail from JIRA

| | | |------------------|-----------------| |Votes | 3 | |Component/s | Source Tooling | |Labels | Bug | |Assignee | @nkcsgexi | |Priority | Medium | md5: 51aa435be00baf4ac468c07bab9de164

blocks:

• SR-146 Move the swift indentation mechanism from SourceKit to libIDE and utilize it for a 'swift-format' tool

Issue Description:

Currently Xcode handles this indentation well:

UIView.animate(
    withDuration: 12.0,
    animations: {
        print("statements have good indentation")
    },
    completion: { done in
        print("statements have good indentation")
    })

However, if the arguments are not broken over multiple lines it looks like this:

UIView.animate(withDuration: 12.0, animations: {
    print("statements have good indentation")
    }, completion: { done in // this shouldn't be indented
        print("statements have weird indentation")
})

Having the print statement at the same level as the closure's closing bracket makes it less clear that the closure has closed. At a glance a programmer may think that completion is an expression inside the first closure.

I expect it to look like this:

UIView.animate(withDuration: 12.0, animations: {
    print("statements have good indentation")
}, completion: { done in // this shouldn't be indented
    print("statements have weird indentation")
})

I'm also happy if it looks like this, although it's a little weird, it's at least consistent:

UIView.animate(withDuration: 12.0, animations: {
        print("statements have good indentation")
    }, completion: { done in // this shouldn't be indented
        print("statements have weird indentation")
    })

I expect indentation to approximately reflect the syntax tree, all arguments at the same level should get the same indentation. So sibling closures should get the same indentation on their closing bracket.

This is discussed in more detail here: https://github.com/apple/swift/pull/3754

[swift-ci]

Comment by shingo (JIRA)

Please fix this.

Promise hard to read.

https://github.com/mxcl/PromiseKit

README.md say

firstly {
    when(fulfilled: fetchImage, fetchLocation)
}.done { image, location in
    self.imageView.image = image
    self.label.text = "\(location)"
}.ensure {
    UIApplication.shared.isNetworkActivityIndicatorVisible = false
}.catch { error in
    self.show(UIAlertController(for: error), sender: self)
}

But, Xcode

firstly {
    when(fulfilled: fetchImage, fetchLocation)
    }.done { image, location in
        self.imageView.image = image
        self.label.text = "\(location)"
    }.ensure {
        UIApplication.shared.isNetworkActivityIndicatorVisible = false
    }.catch { error in
        self.show(UIAlertController(for: error), sender: self)
}