Make "ComplexMethod" rule also ignore "return when" if configured

[dimsuz]

If configured with "ignoreSingleWhenExpression", ComplexMethod should
not only skip "when", but also "return when"

Fixes #1054

[schalkms]

Looks good to me!

[schalkms]

Can you please also test this with single-expression functions. I don't think that the rule reports this atm.

fun f(): Int {
 	return when { ... }
}

[dimsuz]

Do you mean that this rule should treat if-else-if-else-if-else as a single when? Or the opposite, always report them, irrespective to ignoreSingleWhenExpression flag?

[schalkms]

@dimsuz Sry I have updated my comment. I meant that the rule should also report a comment if the single expression syntax is used.

[dimsuz]

Ah, ok! I will test this tomorrow and write back:

• will set ignoreSingleWhenExpression to false, to force the check
• run the rule on the file with return when { } containing threshold + 1 number of when-branches
• the rule should report it as a code smell

[schalkms]

Okay. I think we were talking at cross purposes. Adding the following snippet as another test case should report a violation. Note that I took your test code and just used the single expression syntax. Atm this case is not handled by the ComplexMethod rule.

fun complexMethodWithSingleWhen4(i: Int) = when (i) {
	1 -> "one"
	2 -> "two"
	3 -> "three"
	else -> ""
}

[dimsuz]

Oh, right! I got mixed up between "single expression inside the body" and "single expression function syntax" .

Ok, so I should test that your snippet above

• is causing a violation when ignoreSingleWhenExpression is false (the default)
• is not causing a violation when ignoreSingleWhenExpression is true

In other words fun test() = when {} should behave exactly as fun test() { return when {} }

I hope I got it right this time 🙂.

I will also add test(s) for these cases.

[dimsuz]

I have updated the code and the tests to handle a "function single expression" syntax.

In ComplexMethodSpec there is a spec "reports all complex methods" and ignoring is turned off it indeed reports all "single when" cases as a failures.
And when ignoring is turned on only one case without single whens is reported

[dimsuz]

It turned out that your snippet above is already handled and is reported as ComplexMethod [5/4] when ignoring single when is turned off (though I tested it at home, on current release version of detekt, but it shouldn't have changes I guess). I didn't add a specific test for this case though.