Unreliable on PHP 8.2 and newer #182

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1. Ocramius

   added

   bugSomething isn't workingSomething isn't working

   on Dec 17, 2024
2. Ocramius

   added this to the 1.6.0 milestone on Dec 17, 2024
3. Ocramius

   added a commit that references this issue on Dec 17, 2024

   Removed unused `roave/no-leaks` component

   ...

   07dca12
4. Ocramius commented on Dec 10, 2025

   

   Ocramius

   on Dec 10, 2025

   MemberAuthor

   More actions

   We may need https://www.php.net/manual/en/function.gc-status.php for this - it may give us information on anything not GC'd?

   I couldn't get a really useful example out of it, but only tried for a couple minutes:

   <?php
   
   $iterations = 11111;
   
   class Leaky {
       public array $vals = [];
   }
   
   class BackReference {
       public function __construct(
           public readonly Leaky $backReference,
           public readonly int $counter
       ) {}
   }
   
   $leaky = new Leaky();
   
   var_dump(gc_status()['collected']);
   
   for ($i = 0; $i < $iterations; $i += 1) {
       $leaky->vals[] = new BackReference($leaky, $i);
   }
   
   var_dump(gc_status()['collected']);
   
   (function () use ($iterations) {
       $notLeaky = new Leaky();
       
       for ($i = 0; $i < $iterations; $i += 1) {
           $notLeaky->vals[] = new BackReference($notLeaky, $i);
       }
   })();
   
   var_dump(gc_status());
   
   gc_collect_cycles();
   
   var_dump(gc_status());

   Produces:

   int(0)
   int(0)
   array(4) {
     ["runs"]=>
     int(1)
     ["collected"]=>
     int(0)
     ["threshold"]=>
     int(20001)
     ["roots"]=>
     int(12225)
   }
   array(4) {
     ["runs"]=>
     int(2)
     ["collected"]=>
     int(11113)
     ["threshold"]=>
     int(20001)
     ["roots"]=>
     int(0)
   }
   

   I wonder if we can reliably count the collected counter after multiple test executions, and base ourselves on it?

   ❤️React with ❤️1Reacted by Syndesi
5. Ocramius commented on Dec 10, 2025

   

   Ocramius

   on Dec 10, 2025

   MemberAuthor

   More actions

   Thinking out loud:

   gc_collect_cycles();
   $before = measure_allocated(gc_status());
   
   run("first run", $test);
   
   gc_collect_cycles();
   $run1 = measure_allocated(gc_status());
   
   run("second run", $test);
   
   gc_collect_cycles();
   $run2 = measure_allocated(gc_status());
   
   assert(($run2 - $run1) === ($run1 - $before)); 

   Also being discussed in https://discord.com/channels/1090672946370052166/1091081297759309926/1448347506755895446 ( https://discord.gg/wp6sAjJR )