move default list serializer into an over-loadable parameter

[claytondaley]

Description

Fixes #5391.

[xordoquy]

I'm not sure I get the PR here.
Can't this be achieved with:

class SomeSerializer():
    class Meta:
        list_serializer_class = SomeOtherSerializer

[claytondaley]

For an end-user class yes. But drf-hal-json introduces a HalModelSerializer that will be used by end-user classes. If HalModelSerializer used a Meta class, users would constantly blow it away if they didn't know to inherit the Meta class as well:

class MySerializer(HalModelSerializer):
   class Meta:
        # local configurations (missing ListSerializer configuration)

FWIW I didn't realize that ListSerializer is defined below this class. I would normally reorganize the order of my classes, but I'm not sure if there's anything better to reduce rebase/history hassles.

[claytondaley]

The current workaround avoids this complexity by injecting the value. If DRF makes this change, it can be replaced by a one-line configuration of the Serializer.

[carltongibson]

So, this breaks all the tests.

Given that ListSerializer is a BaseSerializer subclass it’s going to need something more sophisticated.

At that point I’m thinking injecting into the Meta class isn’t actually that bad. It’s a good workaround and avoids adding complexity for a specialist case.

I’m going to close this as is. Happy to reopen if there’s a simple enough solution.