New Cop Style/MultilineMethodCallBraceLayout

[panthomakos]

Identical to Style/MultilineArrayBraceLayout,
Style/MultilineMethodDefinitionBraceLayout, and
Style/MultilineHashBraceLayout, except for method calls.

Includes a change to the MultilineLiteralBraceLayout mixin that allows
for specifying a different method for retrieving a node's children.

[bbatsov]

What are the benefits of having this method?

[panthomakos]

On a method call (on_send) the value of node.children is actually the receiver, method name and then arguments. For instance, parsing

something.foo(1,2,3)

returns (pseudo-code)

[something, :foo, 1, 2, 3]

This is not the case for all other types (hash, array, method definitions) which only return hash elements, array elements or method parameters. This method allows the same code to be re-used for method calls.

[bbatsov]

What about:

method(a, b,
       c, d)

The braces are not symmetrical, but this is super common...

[panthomakos]

@bbatsov That case is accounted for because the first argument is on the same line as the opening brace and the last argument is on the same line as the closing brace. That is valid under the cop's checks. It would be invalid to have either of the following:

method(a, b,
       c, d
)

method(
  a, b,
  c, d)

[panthomakos]

Admittedly these rules make the most sense for hashes and arrays, but I think providing these cops for method definitions and calls makes sense because it provides a consistent way to deal with multi-line "things" surrounded by any kind of brace ([ for array, ( for methods, { for hash).

[bbatsov]

I agree. Just make it clear in the cop's description and in the examples that this is something considered good.

[panthomakos]

I've used the same language for the array, hash and method definition ones. Do you have any suggestions on how to update the language?

original: "Checks that the closing brace in a method call is symmetrical with respect to the opening brace and the method arguments."

suggestion: "Checks that the closing brace in a method call is positioned in the same way as the opening brace with respect to the method arguments and line breaks."

[bbatsov]

I'm on the fence about the two texts. But I was a bit uncertain about the meaning of the wording prior to discussing it with you, so I'm guessing we can do better in terms of clarity. :-)