(SwiftLint) How to write the rule (maybe custom) where it is always "\n"(new line) after the "{" if there is a body?

Question

I am using SwiftLint and I need to have a new line after the "{" if there is a body, for example, this is correct

    func foo() {
        if true { }
    }

but this doesn't seem right

    func foo() {
        if true { print("This print should be on the new line") }
    }

like this

    func foo() {
        if true { 
          print("This print should be on the new line") 
        }
    }

How to do this?

UPD

Thanks, @Bram, there is such a regex

custom_rules:
 newline_block:
    name: "Newline Block"
    regex: 'if \(?\w+\)? \{[ ]*(.+)+[ ]*\}'
    message: "Statement must be on its own line"

The problem is this regex catch all the conditions with one word after the if, like this

if myCondition { } 

and it doesn't matter if braces are on the next line or not, however, this regex doesn't catch conditions like this

if 0 < 1 { print() }

Answer 1

It appears SwiftLint is a bit flaky with the any single character (.), so the closest I got was this

custom_rules:
  newline_block:
    name: "Newline Block"
    regex: "\\{[ ]*(\\S|( +))+[ ]*\\}"
    message: "Statement must be on its own line"

The better regex would be {[ ]*(.+)+[ ]*} (unescaped), but for some reason that doens't work when I run it at Xcode.

This will work for your request with the prints, but the solution does have some drawbacks:

func foo() {
    // No warning
    if true {}
    // Newline Block Violation: Statement must be on its own line (newline_block)
    if true { }
}

And, but I'm not sure if that applies to you as well:

var connection: OpaquePointer? {
    // Newline Block Violation: Statement must be on its own line 
    get { queue.sync { underlyingConnection } }
    // Newline Block Violation: Statement must be on its own line 
    set { queue.sync { underlyingConnection = newValue } }
}