No test added to cover this ? This is not a good sign. bug fixes must have a test to prevent regressions

@stof If you think this is indeed a bug, please give me a starting point and I'd gladly write a test.

Tests are failing… if \Traversable is discarded on purpose how does one specify that an instance is traversable? I'm already specifying traverse: true… There's nothing more I can do according to the docs: http://symfony.com/doc/current/reference/constraints/Valid.html#traverse

Or is it that traverse is not recognized properly? Looks like ClassMetadata and GenericMetadata have different opinions:

• https://github.com/symfony/symfony/blob/2.7/src/Symfony/Component/Validator/Mapping/ClassMetadata.php#L239
• https://github.com/symfony/symfony/blob/2.7/src/Symfony/Component/Validator/Mapping/GenericMetadata.php#L142

One is TRAVERSE, the other one IMPLICIT. And the code is not running through ClassMetadata… Could it be it?

I fixed it by adding the following rule:

Doctrine\Common\Collections\ArrayCollection:
  getter:
    values:
      - Valid:
          traverse: true

Not super intuitive… also the error path looks weird:

Object(HelloFresh\RecipeService\Domain\Recipe\Recipe).steps.values[0].images.values[0].link:

This does not look like a bug to me. But we could indeed improve the documentation. @olvlvl Would you like to open a PR on https://github.com/symfony/symfony-docs?

However, we could add this as a new feature in 4.1 IMO. But we would need a test and existing tests must not fail then.

@xabbuh is there a way to discard the .values[0] part of the path?

@olvlvl What would you expect instead?

I expected ArrayCollection to be traversed without explicitly saying so. But because this is not happening and I use getValues() to validate the items, I have values[*] in the path. Instead of steps.values[0].images.values[0].link I would like to have steps[0].images[0].link. Right now I'm doing a super ugly preg_replace() as I workaround.

The issue with using Traversable is that they are not all rewindable. This means validation would consume the iterator and prevent any further use of it.

@nicolas-grekas You have a very good point here. How about Iterator? They are rewindable.

Not all Iterators a rewindable (even if they have a rewind method, they sometimes throws exceptions in it). An example of this is Generators that implements the Iterator interface but throws if you call rewind after iterating on it (https://3v4l.org/fmCDO).

EDIT: we could do it for instances of IteratorAgregate since they return a new iterator each time you call getIterator but I don't think it's good DX to support IteratorAgregate without supporting Iterator

@olvlvl ok to change to IteratorAggregate and add a test case?

Status: needs work

@nicolas-grekas So, how about I do the same in #25506?

@ostrolucky doable indeed!

@olvlvl OK to finish this one and add a test case ?

@nicolas-grekas Sorry I've been quite busy. I'll try to work on it today.

ping @olvlvl :)

Hi @nicolas-grekas, I wrote a test to validate an instance of a class implementing IteratorAggregate… and it's working out of the box, without any change, and I don't know why: https://github.com/symfony/symfony/pull/24577/files#diff-d46c902789b437519780ee8110ecb5e9R752.

I had no fun writing these few lines of code. The only documentation I found regarding object validation that do not involve annotation shenanigans was in this issue: #11895 (comment).