Null value exception when removing an entity with 1:1 relationship

[jiripudil]

Hi, copying a bug report from Slack so that it can be tracked.

Relevant pieces of entities:

/**
 * @property Mutation $mutation {m:1 Mutation, oneSided=true}
 * @property OrderDelivery|null $delivery {1:1 OrderDelivery::$order, isMain=true, cascade=[persist, remove]}
 */
class Order
{
}

/**
 * @property Order $order {1:1 Order::$delivery}
 */
class OrderDelivery
{
}

When I try to $orm->remove($order) where $order->delivery !== null, orm throws NullValueException because it tries to set null to $order->mutation. A debugging session led me into RemovalHelper::getCascadeQueueAndSetNulls and I am quite certain the culprit is there.

The getRelationships($order) method call here returns:

• $pre contains the order's 1:N relationships which then get removed in cascade. That's good.
• $nulls contains the order's N:1 relationships, including $mutation. This is not an issue by itself but is's a prerequisite to the problem.
• $post contains 1:1 relationships, including $delivery. The helper calls getCascadeQueueAndSetNulls() upon them recursively, and the setNulls call somehow enqueues the relationship's reverse side (i.e. the order) into $queuePersist, even though it's in $queueRemove from the very beginning. Combined with the previous bullet point, it raises the NullValueException because prior to removing things, orm tries to persist the null values in $order.

Since #235, Orm seems to handle this situation for the owning side but not for the reverse side (which is our case). I'm not sure why or what the consequences of introducing it would be.

(Yep, it would likely help to switch the sides of the relationship, but I feel that it should not matter. I want to remove the whole thing anyway.)

orm 4.0.7, dbal 4.0.5

[hrach]

Thank you for this report! Aren't there any other relationships? This seems quite similar to removing a book in our test suite (it has also a 1:1 to Ean and m:1 to other things) and it works. So I'd start with a reproduction.

[jiripudil]

Sure, I've pushed a minimal code to reproduce this to https://github.com/jiripudil/nextras-orm-bug-654

[hrach]

@jiripudil I've cherrypicked the fix to v4 branch, please test if it works for you. Thank you.

[jiripudil]

@hrach Works like a charm, thank you!