Inherit interfaces from all superclasses

[Remy Blank]

When a component class is created, its interfaces are looked up in the class itself and in its direct superclasses. This means that a component class does not inherit the interfaces from its parent's parent, for example.

An example of this pathology can be found in the ticket admin panels​. PriorityAdminPanel inherits from AbstractEnumAdminPanel which in turn inherits from TicketAdminPanel. The interfaces declared in TicketAdminPanel must be re-declared in AbstractEnumAdminPanel, otherwise they are not inherited by PriorityAdminPanel.

I believe this is an oversight, and interfaces should be inherited by all superclasses.

[Remy Blank]

Small correction: the issue occurs if GrandParent implements an interface, Parent implements another one, and Child implements a third one. In that case, Child doesn't implement the interface of GrandParent.

[Remy Blank]

Inherit interfaces from all superclasses.

[Remy Blank]

The patch above fixes the issue, and adds a test case for this situation.

Thoughts?

[Christian Boos]

I tried to see if the current behavior could be useful somehow, but didn't see any real benefit, so I think it's OK to do that change.

[Remy Blank]

Patch applied in [8685].

[Remy Blank]

[8694] ensures that a component isn't registered more than once as implementing an interface. This could happen in code relying on the old behavior.

It also removes an obsolete test that wasn't working anyway.