Variable undefined when defined in prior if block

[dantleech]

Summary of a problem or a feature request

In the below example the two conditionals both evaluate to true based on the same variable. If the variable is true the code within each block should be evaluated and $foo should therefore be defined in the second block, but Phpstan reports that it might be undefined

 ------ ------------------------------------- 
  Line   analyzed.php                         
 ------ ------------------------------------- 
  4      ... 
  10     ...
  11     Variable $foo might not be defined.  
 ------ ------------------------------------- 

Code snippet that reproduces the problem

            <?php

            $baz = true; // ignore: could be false|true at runtime
            if ($baz) {
                $foo = 'asd';
            }

            if ($baz) {
                $bar = $foo; 
            }

https://phpstan.org/r/112e67a0d4bd81232da6a687b6605d42

[dantleech]

There is a potentially related issue here: https://phpstan.org/r/07a9e0d5cc770c25203bcc3bc3b9c9b1

<?php

function bar($foo = null) {
  if ($foo !== null) {
	$someBoolean = false;
  }

  if ($foo !== null && $someBoolean === false) {
  }
}

 ------ --------------------------------------------- 
  Line   analyzed.php                                 
 ------ --------------------------------------------- 
  8      Variable $someBoolean might not be defined.  
 ------ ---------------------------------------------

In the above case $someBoolean will not be evaluated if $foo is null, so it should be OK.

[ondrejmirtes]

Hi, this is hard to solve. There are other issues like this: https://github.com/phpstan/phpstan/milestone/12 I might tackle this one day, but it's not a priority.

Meanwhile, you should always use isset in the second condition.

[dantleech]

ok thanks, no worries.

Meanwhile, you should always use isset in the second condition.

I think the above is valid (even if horrible - not my code 🙄 ) $someBoolean will not be evaluated if the left side of the && is false.

[ondrejmirtes]

Yeah but I’m suggesting analyser-friendly code that will stop reporting that error. ne 29. 7. 2018 v 11:32 odesílatel dantleech <notifications@github.com> napsal:

ok thanks, no worries. Meanwhile, you should always use isset in the second condition. I think the above is valid (even if horrible - not my code 🙄 ) $someBoolean will not be evaluated if the left side of the && is false. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#1306 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAGZuEqLxlry2Ew8DxKBSKDCjDdIw0dDks5uLYE2gaJpZM4Vk7FK> .

-- Ondřej Mirtes

[dhaarbrink]

+1 from me, I have also just run into this problem. Following thread.

[morrisonlevi]

This is common for things that are only executed in debug mode; see https://phpstan.org/r/1df6d7d1-6a34-499d-93d1-eab18dcef390. Normally there would be other things between the two ifs, of course.

[ondrejmirtes]

Fixed: phpstan/phpstan-src@54284c8

[github-actions]

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