Add preserve_empty_objects support

[Foxprodev]

Q	A
Branch?	2.6
Tickets	#38192 ?
License	MIT
Doc PR

CollectionNormalizer currently replacing ArrayObject with an empty array

More about main idea discussed here symfony/symfony#28363

Feel free to help me with test case and test location. Thank you 😄

[Foxprodev]

Or maybe CollectionNormalizers should stop supporting empty Countables

[snoob]

+1 for this :)

WDTY about calling the normalizer on normalizeRawCollection and fully delegate the "PRESERVE_EMPTY_OBJECTS" management to Symfony ?
Once fixed, we will be able to use this symfony/symfony#42240 on symfony 5.4

return $this->normalizer->normalize($this->normalizeRawCollection($object, $format, $context));

I have found a temporary workaround. Add "PRESERVE_EMPTY_OBJECTS" in your entity normalizationContext and declare your property as stdClass instead of array. It will be serialized as empty object instead of empty array.

[Foxprodev]

Once fixed, we will be able to use this symfony/symfony#42240 on symfony 5.4

Wow this PR seems terribly bad for me. It breaks list array at all. I am currently using PRESERVE_EMPTY_OBJECTS in global context and this behaviour feels expected for me

[snoob]

Wow this PR seems terribly bad for me. It breaks list array at all. I am currently using PRESERVE_EMPTY_OBJECTS in global context and this behaviour feels expected for me

About this PR, you shouldn't worry about it :) think it won't break your current behavior. You will just be able to override this for a specific property.

[Foxprodev]

About this PR, you shouldn't worry about it :) think it won't break your current behavior. You will just be able to override this for a specific property.

According to PR ObjectNormalizer will convert all empty arrays to objects, when PRESERVE_EMPTY_OBJECTS enabled. It sounds weird for me and breaks BC.
But yes it's not about my current PR 😄

[Foxprodev]

symfony/symfony#42240 irrelevant. Maybe I should rework this PR to support symfony/symfony#42297 in advance
All should work fine

[Foxprodev]

Added tests

[soyuka]

Could you target main?

[Foxprodev]

@soyuka done

[snoob]

You must rebase your branch there are conflicts

[snoob]

Thank :)

[alanpoulain]

Superseded by #4999, thank you!