false positive: Variable $variableDefinedWithinForeach might not be defined.

[stesie]

PHPStan since 0.9 doesn't detect early continue of foreach loop wih continue 2 in foreach/switch loop

Demo: https://phpstan.org/r/62fe427842b4f0c162961a5eaf75a158

<?php declare(strict_types = 1);

foreach (['foo', 'bar'] as $loopValue) {
        switch ($loopValue) {
        case 'foo':
                continue 2;

        case 'bar':
                $variableDefinedWithinForeach = 23;
                break;

        default:
                throw new \LogicException();
        }

        echo $variableDefinedWithinForeach;
}

The echo statement is actually only reachable via "bar"-case and there the variable in question is defined. PHPStan doesn't consider that continue 2 breaks the loop early and considers the variable undefined, hence triggering "might not be defined"

[ondrejmirtes]

Hi, yes, support for break X and continue X is really hard to implement and not yet properly supported.

On Fri, 1 Dec 2017 at 11:43, Stefan Siegl ***@***.***> wrote: PHPStan since 0.9 doesn't detect early continue of foreach loop wih continue 2 in foreach/switch loop Demo: https://phpstan.org/r/62fe427842b4f0c162961a5eaf75a158 <?php declare(strict_types = 1);foreach (['foo', 'bar'] as $loopValue) { switch ($loopValue) { case 'foo': continue 2; case 'bar': $variableDefinedWithinForeach = 23; break; default: throw new \LogicException(); } echo $variableDefinedWithinForeach;} The echo statement is actually only reachable via "bar"-case and there the variable in question is defined. PHPStan doesn't consider that continue 2 breaks the loop early and considers the variable undefined, hence triggering "might not be defined" — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#651>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAGZuIXNoI-OOLWgL2iuuINxa4_jvHVoks5s79g7gaJpZM4QyKmR> .

-- Ondřej Mirtes

[muglug]

Hi, yes, support for break X and continue X is really hard to implement and
not yet properly supported.

If you want pointers, I think this covers pretty much everything? https://github.com/vimeo/psalm/blob/66fa08148805d4935218b9593885dd3e0af1394d/src/Psalm/Checker/Statements/Block/LoopChecker.php

Figuring out whether what a given set of statements do is in https://github.com/vimeo/psalm/blob/66fa08148805d4935218b9593885dd3e0af1394d/src/Psalm/Checker/ScopeChecker.php#L56 and was key for me in cracking the whole break/continue code.

A very brief sketch of the system of contexts it creates is here: vimeo/psalm#365 (comment), would be happy to go into more depth while the thing is still relatively fresh in my mind.

And finally, https://github.com/vimeo/psalm/blob/66fa08148805d4935218b9593885dd3e0af1394d/tests/LoopScopeTest.php contains a whole bunch of tests for this stuff. Allowed me to go pretty crazy with a refactor without worrying about regressions

[ondrejmirtes]

@muglug I'm afraid that your code is not applicable here because PHPStan uses a completely different architecture. The whole logic of existing variables and their types after a series of conditions and loops is handled here:

https://github.com/phpstan/phpstan/blob/master/src/Analyser/NodeScopeResolver.php#L1188 (NodeScopeResolver::lookForAssignsInBranches))) and in this object (https://github.com/phpstan/phpstan/blob/master/src/Analyser/LookForAssignsSettings.php)

So I will have to figure out by myself but after the latest refactoring, I don't think it will be a big problem.

[o5]

I've similar issue with switch and "might not be defined".

<?php declare(strict_types = 1);

$var = 'foo';
switch ($var) {
	case 'foo':
		$bar = 'foo';
		break;
	default:
		throw new \InvalidArgumentException(); // some comment
}

in_array($bar, [], true);

 ------ ------------------------------------- 
  Line   analyzed.php                         
 ------ ------------------------------------- 
  12     Variable $bar might not be defined.  
 ------ ------------------------------------- 

Demo: https://phpstan.org/r/bbcef57b6fecc961a357a9d50122838e

It works when I remove comment // some comment on line 9. It's very strange.

[o5]

Sorry, I just tried it on master and there is probably fixed by 870e449.

[ondrejmirtes]

Fixed: phpstan/phpstan-src@31fcad6

[github-actions]

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