Add ShortenElseIfRector

[keulinho]

Fixes #1945

[TomasVotruba]

Very nice job!

I've added few comments

[TomasVotruba]

This is pretty difficult to understand recursion.
Could you think of more readable syntax?

[keulinho]

Removed the coalesc and made it more verbose,
hopefully that makes it clearer

Do you have any better ideas in mind how to clarify this?

[TomasVotruba]

I'm not sure why have you chosen this approach, so I don't even understand the idea to describe it

I always try to avoid calling the self or another Rector in a Rector, but rather decopule a method with meaning captured in it's name

[keulinho]

Ok the reason behind the recursion is that we get rid of the original nested If_ node, but this rector runs only on If_ nodes.
This means after refactoring the top-level If_ we won't detect any more else/if condition that we could refactor inside that if statement, because now it is an Elseif_ Node.
Consider the example from the recursive fixture:

    public function run()
    {
        if ($this->cond1) {
            $this->doSomething();
        } else {
            if ($this->cond2) {
                $this->doSomething();
            } else {
                if ($this->cond3) {
                    $this->doSomething();
                }
            }
        }
    }

In that case we would move the if ($this->cond2) statement up and combine it to the elseif ($this->cond2). By this refactoring our rector doesn't run for the nested if ($this->cond3), it would get refactored if we run the rector a second time.
Therefore we have to run the refactoring on the inner if ($this->cond3) before applying the refactoring on the outer if ($this->cond3).

I hope this clarifies the need for recursion, i'll try to express this inside the code

[TomasVotruba]

I see

I hope this clarifies the need for recursion, i'll try to express this inside the code

That would be perfect, so this comment is not needed to understand the mechanism

[TomasVotruba]

👍 Thank you