fix(node-visitor): Ensure that missing statements do not crash in visitor

[MattyRad]

Hello,

I'm not too familiar with assertions in PHP, so perhaps the expectation of this library is that you must have assertions configured in a certain way. If so, feel free to close the issue/PR.

complexity/src/Visitor/ComplexityCalculatingVisitor.php

Line 51 in 9fb9f61

assert(is_array($statements));

Nevertheless, I'm encountering an error while computing complexity on interfaces.

SebastianBergmann\Complexity\ComplexityCalculatingVisitor::cyclomaticComplexity(): Argument #1 ($statements) must be of type array, null given, called in .../vendor/sebastian/complexity/src/Visitor/ComplexityCalculatingVisitor.php on line 61

I understand that interfaces have no complexity... so another solution is to filter interfaces and prevent them from ever having their complexity computed. But it would be nice to be able to scan an entire directory without having to perform tedious filtering.

If you'd prefer not to blanket return null, checking the parent node might also work:

        if ((!$node instanceof ClassMethod && !$node instanceof Function_) || $node->getAttribute('parent') instanceof Interface_) { return null; }

[sebastianbergmann]

perhaps the expectation of this library is that you must have assertions configured in a certain way

I use assertions such as assert(is_array($statements)); do document assumptions. Static analysis tools such as Psalm or IDEs such as PhpStorm use this information to reason about the code. Furthermore, I have configured

zend.assertions=1
assert.exception=1

so that assert() statements are evaluated by the PHP runtime and result in an exception when they do not hold.

[sebastianbergmann]

Please rebase your branch against main so that you get af325e1. This should fix the Composer-related build failures. Sorry for the inconvenience.

[sebastianbergmann]

Nevermind, I just merged your test and changed the visitor to ignore interfaces. Thank you!