BackedEnum::from()/tryFrom()/cases() return values having no relation to this enum

[cracksalad]

Description

The following code:

<?php
declare(strict_types=1);

namespace entity\type;

enum Priority: string {
  case LOW = 'low';
  case MEDIUM = 'medium';
  case HIGH = 'high';
}

<?php
declare(strict_types=1);

namespace recommendation;

use entity\type\Priority;
// [...]

class Handler {
  // [...]
  protected function parsePriority(MyClass $target, array $results): void {
    if(isset($results['priority']['value'])){
      $priority = Priority::tryFrom($results['priority']['value']);

      App::getLogger()->debug('got priority value', [  // Monolog logger
        'value' => $priority,
        'original' => $results['priority']['value'],
        'cases' => OptimizedActionPriority::cases()
      ]);

      if($priority !== null){
        $target->setPriority($priority);  // line 206
      }
    }
  }
// [...]

<?php
declare(strict_types=1);

namespace entity;

use entity\type\Priority;

class MyClass {
  // [...]
  public function setPriority(Priority $priority): void {  // line 59
    // [...]
  }
  // [...]
}

Resulted in roughly 80 % of cases in the expected output, but in 20 % of cases in this output:

• Log output (note that opis/json-schema is a dependency of my project`):

got priority value {"value":{"Opis\\JsonSchema\\Parsers\\Keywords\\MinimumKeywordParser":[]},"original":"medium","cases":[{"entity\\type\\OptimizedActionPriority":"low"},{"Opis\\JsonSchema\\Parsers\\Keywords\\MinimumKeywordParser":[]},{"entity\\type\\OptimizedActionPriority":"high"}]}

• Output:

[object] (TypeError(code: 0): entity\\MyClass::setPriority(): Argument #1 ($priority) must be of type entity\\type\\Priority, Opis\\JsonSchema\\Parsers\\Keywords\\MinimumKeywordParser given, called in src/recommendation/Handler.php on line 206 at src/entity/MyClass.php:59)
  [stacktrace]
  #0 src/recommendation/Handler.php(206): entity\\OptimizedAction->setPriority()
  #1 src/recommendation/[...]: recommendation\\OptimizedActionHandler->parsePriority()
  // [...]
  #6 [internal function]: {closure:scripts/worker/gearman-worker.php:131}()
  #7 scripts/worker/gearman-worker.php(221): GearmanWorker->work()
  #8 {main}

But I expected this output instead:

• Log output:

got priority value {"value":{"entity\\type\\OptimizedActionPriority":"low"},"original":"low","cases":[{"entity\\type\\OptimizedActionPriority":"low"},{"entity\\type\\OptimizedActionPriority":"medium"},{"entity\\type\\OptimizedActionPriority":"high"}]}

Notes:

• Sadly, I was not (yet) able to reproduce this in a minimal example and I did not find any reference online describing a similar behavior. I am a little desperate right now
• All the PHP code runs in a CLI context rather than FastCGI and is called via a Gearman worker (although the observed behavior should not happen, regardless of the context, I guess)
• The observed $priority values are either correct or randomly chosen class instances, that were used by the same script during the same execution. So, it might be a memory access issue?!
• The real example above is especially weird, since the "low" value from cases() is actually correct, while the tryFrom("low") value is not. You see the randomness here?
• Same behavior is to observe replacing tryFrom() with from() (and no ValueError is thrown)
• I tried renaming the enum (I assumed a name collision of some sort), although I can not rename the values since they need to match the API responses

PHP Version

Tested with

PHP 8.4.19 (cli) (built: Mar 10 2026 15:51:04) (NTS gcc x86_64)
Copyright (c) The PHP Group
Built by Remi's RPM repository <https://rpms.remirepo.net/> #StandWithUkraine
Zend Engine v4.4.19, Copyright (c) Zend Technologies
    with Zend OPcache v8.4.19, Copyright (c), by Zend Technologies

as well as

PHP 8.3.30 (cli) (built: Jan 13 2026 22:36:55) (NTS gcc x86_64)
Copyright (c) The PHP Group
Zend Engine v4.3.30, Copyright (c) Zend Technologies
    with Zend OPcache v8.3.30, Copyright (c), by Zend Technologies

Operating System

AlmaLinux 9

[iluuu1994]

Hi @cracksalad. Memory corruption is possible. Two questions:

• Are you using the JIT?
• Do you have any 3rd party extensions enabled?

Can you try without both and see if it resolves your issue?

[cracksalad]

Hi @cracksalad. Memory corruption is possible. Two questions:

* Are you using the JIT?

* Do you have any 3rd party extensions enabled?

Can you try without both and see if it resolves your issue?

Thank you for your tips!

• I did not configure JIT until now (which I assume means "tracing" for 8.3 and "disable" for 8.4). It is disabled now.
• I use a few third party extensions. Most of them I would describe as passive like imagick, memcached, igbinary, lz4, msgpack, gnupg and gearman. In this context only memcached and gearman are really used. I will try to disable as many as possible without breaking anything.

Need to wait and observe for a bit, before I can tell if the behavior has changed.

[iluuu1994]

Thanks! It's worth noting that even applications you consider passive can have an effect down the line. Frequently, the effects of memory corruption aren't immediately evident.