Serialization of union type will return bool(true) instead of int(1)

[fabianerni]

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

Steps required to reproduce the problem

1. Create an entity with a (virtual) property with a union (return) type definition (ex: function getValue(): int|string|bool|float)
2. Serialize the entity/property to JSON and return int(1) from getValue(). Expect int(1) in the serialized data
3. Serializer will detect a boolean value instead of an int and serialize bool(true)

Expected Result

• For serialization, the returned types should be handled strict. So if an int(1) is returned, it should be int(1) and not bool(true)

Actual Result

• int(1) is detected as primitive type bool and will get serialized as bool

Related Code

• UnionHandler::testPrimitive()
• TypePropertiesDriver::reorderTypes()

Problem

• Despite the doc block on TypePropertiesDriver::reorderTypes(), which says int should come before bool, bool is sorted before int and will be tested first in UnionHandler::testPrimitive().
• UnionHandler::testPrimitive() uses dynamic type conversions ((string) and (bool)) to check for the types. Therefore, int(1) will first get checked for bool and the dynamic conversion will result in a positive test.

Bug

Will result in a positive match for bool type for int(1) and int(0)
(string) (bool) $data === (string) $data
https://github.com/schmittjoh/serializer/blob/master/src/Handler/UnionHandler.php#L134

Suggested Solution

(Sorry for not providing a pull request. But I'm not that experienced with the internals of the serializer compontent and such a change might have unexpected results I'm not aware of).

• Change the type order in TypePropertiesDriver::reorderTypes(), so int is checked before bool
• Make the checks in UnionHandler::testPrimitive() more strict, at least for serialization, since here we can expect exact types coming from the entities

[scyzoryck]

@fabianerni thanks for report! The proposal for changes makes sense - could you please make pull request with the changes please? I can help in case of issues.

Best, Marcin.