Support retrieving lower bound from TypeVariable in Collection attribute

[amoscatelli]

#579

The issue is related to TypeVariable having a GenericDeclaration different from the expected inherited one.
In the example described in the issue, the GenericDeclaration is FindRequestDTO, and that doesn't match with FindCriteriaDTO.

This is an issue for https://github.com/eclipse-ee4j/yasson/blob/master/src/main/java/org/eclipse/yasson/internal/VariableTypeInheritanceSearch.java#L98

Tell me if you need a more structured approach.

Thank you

[amoscatelli]

@Verdent what do you think ?

[Verdent]

Hi @amoscatelli ,
I am sorry, I am just completely preoccupied on other project. I will definitely check that out once I have time :-)

Thank you for your contribution!
I am sorry it took me so long to answer and so you have decided to close the PR.

[amoscatelli]

@Verdent I closed the issue because I understood the issue is not about typevariable alone, but is about a combination of typevariable and something else.

I need to research more, then I'll update the issue I opened before and if you want I'll repone the pull request.

[amoscatelli]

@Verdent hi again
I wrote a test to show you the real issue

The issue is with TypeVariable (and NOT WildcardVariable) used to define a Collection of a wrapper generic class attribute.
(I reproduced the issue with both Collection and Map to tell the truth).

To get the TypeVariable (and not the WildcardVariable) I use reflection (see the getDeclaredField in the test).

The same actually works if you use the generic to define a non collection attribute, in other words if you remove Collection from the attribute.

The same works if you don't use a wrapper class too.

In other words, these combinations work :

private Collection<T> value;
private AnotherGenericTestClass<Integer, T> value;
private T value;

This combination doesn't work :

private Collection<AnotherGenericTestClass<Integer, T>> value;

By patching Yasson internal TypeUtils I made this work, but I can't exclude there is something else wrong behind.

Please let me know.

[redmitry]

This patch made my day (after loosing another one).

I have a generic API where actual entries are not specified;

public List<Resultset<T>> getResultSets() {
    return result_sets;
}

The server may put any jsonb annotated entries, but serialization on server side fails without the patch.

D.

P.S. I have attached the unit test for my case in a hope the patch is accepted.
yasson-test-580.zip

[redmitry]

The patch definitely fixes the issue.