Rule Request: multiline_arguments: Allow enforcing only after first closure

[ldiqual]

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Rule Request

My proposal is to add a new configuration for multiline_arguments that would allow enforcing the rule only after the first closure.

For instance, I would like to handle this case:

UIView.animate(withDuration: duration, animations: {
    // animations
}, completion: { _ in
    // completion
})

However with the current defaults, I have to write it this way:

UIView.animate(
    withDuration: duration,
    animations: {
        // animations
    }, completion: { _ in
        // completion
    }
)

You would also be able to pass more inline arguments before animations.

1. Why should this rule be added? Share links to existing discussion about what
   the community thinks about this.

I believe that the animate + completion case above is common across iOS codebases and that the first style above is a common way to express it.

Ray Wenderlich's swift style guide passes animations on the same line: https://github.com/raywenderlich/swift-style-guide#closure-expressions

2. Provide several examples of what would and wouldn't trigger violations.

Doesn't trigger

call(a: a, b: {

}, c: {

})

call(a: a, b:b, c: {

}, d: {

})

Triggers

call(a: a, b:b,
  c: c, d: {

  }, d: {

  }
)

call(a: a, b: {

}, c: {

}, d: d, e: e)

3. Should the rule be configurable, if so what parameters should be configurable?

A name for such option could be:

• allow_first_closure_on_same_line
• only_enforce_after_first_closure

Hard to describe the intent in a generic way and I'd love input from you guys.

4. Should the rule be opt-in or enabled by default? Why?
   See README.md for guidelines on when to mark a
   rule as opt-in.

The option would be enabled by default for the multiline_arguments rule, since this is a common case as described above.

[tinder-garricnahapetian]

I think this is a great idea. Would it be hard to implement? I could give it a try. Where would I start?

[jpsim]

Shouldn't be too hard. Start in MultilineArgumentsRule.swift and MultilineArgumentsConfiguration.swift.

[hani-ibrahim]

any updates on this?

[maciesielka]

Took a stab at adding this in #2281

[marcelofabri]

Implemented by @maciesielka in #2281 🎉