Unable to convert self-referring instances to resources

[weierophinney]

• [x] Are you fixing a bug?
  • [x] Detail how the bug is invoked currently.
  • [x] Detail the original, incorrect behavior.
  • [x] Detail the new, expected behavior.
  • [x] Base your feature on the master branch, and submit against that branch.
  • [x] Add a regression test that demonstrates the bug, and proves the fix.
  • [ ] Add a CHANGELOG.md entry for the fix.

Imagine the following example:

class Parent {
    /** @var Child[] */
    public $childs;
    public function addChild(Child $child) {
        $this->childs[] = $child;
        $child->parent = $this;
    }
}
class Child {
    /** @var Parent */
    public $parent;
}

$parent = new Parent();
$parent->addChild(new Child());
$parent->addChild(new Child());

$generator->fromObject($parent, $request);
// the call above will result in an error:
// Error : Maximum function nesting level of '256' reached, aborting!

Other examples: One-To-One, Bidirectional One-To-One, Self-referencing One-To-Many, Bidirectional One-To-Many, Self-referencing Many-To-Many, Bidirectional Many-To-Many, Self-referencing

The zfcampus/zf-hal component solved this issue by using a $maxDepth property in metadata which is then passed through here and here.

Using this approach would result in a change of the \Zend\Expressive\Hal\ResourceGenerator\StrategyInterface interface which would be a BC break.

I would love if someone comes up with an alternate solution which will not break BC.

---

Originally posted by @tobias-trozowski at https://github.com/zendframework/zend-expressive-hal/pull/57

[weierophinney]

still smells. but should fit now.

---

Originally posted by @tobias-trozowski at https://github.com/zendframework/zend-expressive-hal/pull/57#issuecomment-486763165

[weierophinney]

@tobias-trozowski I've rebased your branch to squash several commits and remove both the revert commits and the commits they were reverting; the diff ends up the same as you had committed previously.

In the future, feel free to use git rebase -i + git push -f liberally when working on a patch; these help ensure the history is easier to follow, particularly when removing patches.

I'll review again now to see where we are in terms of ability to merge.

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Originally posted by @weierophinney at https://github.com/zendframework/zend-expressive-hal/pull/57#issuecomment-491986956

[guliano]

Any news on this issue?

[weierophinney]

@guliano Not yet. We're still finishing out tasks related to the Laminas migration, so it may be a few weeks.