Handle union types for typed properties and docblocks

[dgafka]

This handle union types for typed properties and DocBlock type resolver.

The solution allows for defining union types for above, which was previously failing during cache building phase.
As union type is non implicit in what we are actually serializing / deserializing, we are not trying to recognize which type user want to use in specific context.

How does serialization works?
Serializing knows which type to use, as it actually holds the value that is going to be serialized. It use that value to infer the type and do the serialization.

How does deserialization works?
The deserialization will throw an exception as we can't guess, which type user would like to pick.
If developer will define Type Attribute, it will be chosen as default one.
This is a place for improvement. Possible we could introduce custom union deserializing handler, that would decide on his own what class he would like to deserialize too.

Q	A
Bug fix?	yes
New feature?	yes
Doc updated	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets	#1282 #1302
License	MIT

[dgafka]

ping @yyaremenko @gam6itko :)

[goetas]

i'm sorry for the delay, @dgafka could you please rebase this?

[dgafka]

@goetas branch is up to date with master now :)
I am not sure, how to fix phpstan or phpcs for lower PHP versions, can you do it?

[gnat42]

Hello, trying to upgrade a project to 8.1 and running into failed tests because of this. How can I help to get this merged/tested etc?

[davidwindell]

Just tested this on our app and can confirm it seems to work well for us.

[dgafka]

Hey @goetas,
Can this be merged? :)

[scyzoryck]

@dgafka - Could you take a look at the code style issues that has been reported by the coding standard, please? I believe they can be fixed automatically by the tool. Also you need to exclude your fixture from PHPStan analysis - as in CI it is running with PHP7.4 that do not support union types.

[dgafka]

@scyzoryck how to fix that:

  Line   tests/Metadata/Driver/TypedPropertiesDriverTest.php                                                                                                                            
 ------ ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 
  15     ParseError (syntax error, unexpected '|', expecting variable (T_VARIABLE)) thrown while looking for class JMS\Serializer\Tests\Fixtures\TypedProperties\UnionTypedProperties.  
         💡 Learn more at https://phpstan.org/user-guide/discovering-symbols                                                                                                             
  53     ParseError (syntax error, unexpected '|', expecting variable (T_VARIABLE)) thrown while looking for class JMS\Serializer\Tests\Fixtures\TypedProperties\UnionTypedProperties.  
         💡 Learn more at https://phpstan.org/user-guide/discovering-symbols 

as excluding it from phpstan analyse does not change a thing:

    excludePaths:
        - %currentWorkingDirectory%/src/Annotation/ReadOnly.php
        - %currentWorkingDirectory%/tests/Fixtures/TypedProperties/UnionTypedProperties.php

[dgafka]

I've put the test under phpstan ignore too. Tests are passing now.

[dgafka]

Extracted separate phpstan analysis for PHP 7.4.
The rest of the versions are running against those files :)

[scyzoryck]

Thanks! Looks good for me! @goetas - Could you take a look, please?