Fix pruning all collections in table for inherited elements.

[DnwK98]

When we have two collections with inherited types in one entity, in this example it's PetStore containing Cat and Dog

Cat extends Pet
Dog extends Pet
// Cat and dog are stored in same table using entity_discriminator

PetStore
   Cat[] cats
   Dog[] dogs

And we clear one of them using clear(), second gets cleared too, due to DELETE statement without proper filter.

I think it's bug.

There is fix and test for it.

Bypass before this is merged:
Instead of using

collection.clear()
// or
collection = new ArrayCollection(newElements)

load collection, and clear elements manually in your code

foreach(collection as element){
    collection.removeElement(element)
}
foreach(newElements as newElement){
    collection.add(newElement)
}

[DnwK98]

Can I do something to help in review?

[beberlei]

I am not sure if this will work for joined table inheritance as well, can you use joined inheritance instead of single table in the test please? Single table is a special case of joined table

[DnwK98]

This change doesn't affect joined inheritance, because its collections are removed using deleteJoinedEntityCollection() instead of deleteEntityCollection()

For joined inheritance this bug doesn't appear, because separate collections are filtered using JOIN to exact tables.

...
        $sql = $query->getSQL();
        //   SELECT c0_.id AS id_0 FROM Dog d1_
        //        INNER JOIN collection_with_inheritance_pet c0_ ON d1_.id = c0_.id WHERE d1_.petStore_id = ?

        assert(is_string($sql));
        $statement = 'INSERT INTO ' . $tempTable . ' (' . $idColumnList . ') ' . $sql;
        //   INSERT INTO collection_with_inheritance_pet_id_tmp (id)
        //        SELECT c0_.id AS id_0 FROM Dog d1_
        //            INNER JOIN collection_with_inheritance_pet c0_ ON d1_.id = c0_.id
        //        WHERE d1_.petStore_id = ?

        $parameters = array_values($sourceClass->getIdentifierValues($collection->getOwner()));
        $numDeleted = $this->conn->executeStatement($statement, $parameters);

        // 3) Delete records on each table in the hierarchy
        $classNames = array_merge($targetClass->parentClasses, [$targetClass->name], $targetClass->subClasses);

        foreach (array_reverse($classNames) as $className) {
            $tableName = $this->quoteStrategy->getTableName($this->em->getClassMetadata($className), $this->platform);
            $statement = 'DELETE FROM ' . $tableName . ' WHERE (' . $idColumnList . ')'
                . ' IN (SELECT ' . $idColumnList . ' FROM ' . $tempTable . ')';
            //   DELETE FROM collection_with_inheritance_pet
            //   WHERE (id) IN (SELECT id FROM collection_with_inheritance_pet_id_tmp)

            $this->conn->executeStatement($statement);
        }
...

[DnwK98]

As it fixes bug maybe it should target 2.19.x

[DnwK98]

Fixed in the meantime in #11501