Serialize Generator

[simPod]

Q	A
Bug report?	no
Feature request?	yes
BC Break report?	no
RFC?	no

Steps required to reproduce the problem

function getData() {
   yield 1;
   yield 2;
}
...
$classToSerialize = new ClassToSerialize($this->getData()); // Save getData()'s result to inner iterable-typed property
// annotated with * @Serializer\Type("array<int>")

2. $data = $serializer->serialize($classToSerialize, ...);

Expected Result

• $data contains array [1, 2], Generator was converted to array

Actual Result

• $data contains empty array, Generator was not converted to array

What do you think of auto converting generators to arrays when serializing?

[scyzoryck]

I can see two ways to add this feature.

1. In SerializationGraphNavigator we can add

if ($data instanceof \Iterator) {
    return $this->visitor->visitArray(iterator_to_array($data), $type);
}
return $this->visitor->visitArray((array) $data, $type);

2. Breaking change in SerializationVisitorInterface

public function visitArray(iterable $data, array $type);

@goetas
What do you think about it? 🤔

[goetas]

Why not adding a custom handler for Generator and to exactly the same thing as for ArrayCollection ?

See https://github.com/schmittjoh/serializer/blob/master/src/Handler/ArrayCollectionHandler.php

[goetas]

Solved in #1034