Swiftlint Regex - Custom rule regex not working

Question

I'm trying to add a swiftlint rule about function indentation declaration. (Rule 1.9 of https://github.com/linkedin/swift-style-guide#1-code-formatting). Which function declaration of multiple parameters should like this:

func myFunctionWithManyParameters(parameterOne: String,
                                  parameterTwo: String,
                                  parameterThree: String)

---

The regex I wrote is

((func|init)[\s\?]?.*(?<!(,|\)|\{|\}))\n)

and another approach since negative lookbehind may not support

((func|init)((?!.*(,|\)|\{|\})).+))

But lint does not report any warning. Is regex incorrectly written or swiftLint incorrectly configured?

---

I've been test the following cases in online regex editor, passed. But no warning in swiftlint.

// Should Pass: Method with parameters
func foo(_ param1: String) {
}

// Should Pass: Method with parameters
func foo2(_ param1: String) {}

// Should Pass: Method with parameters in same line
func foo3(param1: String, param2: Int) {
}

// Should Pass: Method with parameters in multiple lines
func foo4(param1: String,
          param2: Int) {
}

// Should Pass: Method with no parameter
func foo5() {
}

// Should Pass: Protocol
protocol Foo {
    func foo6()
}

// Should Fail
func foo7(
    _ param1: String) {
    }

// Should Fail
func foo(
    param1: String,
    param2: Int) {
    }

Swiftlint configuration:

custom_rules:
  func_multiline_parameters:
    name: "Follow Xcode's recommended function declaration indentation style that spans multiple lines"
    regex: ((func|init)[\s\?]?.*(?<!(,|\)|\{|\}))\n)
    message: "1.9 We follow Xcode's recommended indentation style (i.e. your code should not change if CTRL-I is pressed). When declaring a function that spans multiple lines, prefer using that syntax to which Xcode, as of version 7.3, defaults."
    severity: warning

Answer 1

For starters SwiftLint regexes need to be double escaped Eg. ((func|init)((?!.*(,|\\)|\\{|\\})).+))

But check first that swiftlint's vertical_parameter_alignment rule doesn't already achieve what you're after