Serialization

Using (un-)serialize() on a collection is not a supported use-case and may break when changes on the collection's internals happen in the future. If a collection needs to be serialized, use toArray() and reconstruct the collection manually.

.. code-block:: php

$collection = new ArrayCollection([1, 2, 3]);
$serialized = serialize($collection->toArray());

A reconstruction is also necessary when the collection contains objects with infinite recursion of dependencies like in this json_serialize() example:

.. code-block:: php

$foo = new Foo();
$bar = new Bar();

$foo->setBar($bar);
$bar->setFoo($foo);

$collection = new ArrayCollection([$foo]);
$json       = json_serialize($collection->toArray()); // recursion detected

Serializer libraries can be used to create the serialization-output to prevent errors.