Description

After updating from Symfony 5.3 to Symfony 5.4, our code started to crash. This is because new PhpStanExtractor was introduced that was prioritized above older extractors. This extractor started to return null type and hence serializer failed to denormalize our objects.

It returns null, because this is a UnionTypeNode containing ConstTypeNode and IdentifierTypeNode (null). However PhpStanTypeHelper doesn't handle ConstTypeNode and hence symfony/property-info will return null only.

Example

class Foo
{
   /**
     * @return PageType::*|null
     */
    public function getDynamicPageType(): ?string
    {
        return rand(0, 1) ? PageType::FOO : null;
    }
}

class PageType {
    const FOO = 'foo';
}

On Symfony 5.3, this returns string|null. On Symfony 5.4, because PhpStanExtractor was added which doesn't correctly handle unions, it returns null.