Contradictory read_only and required arguments on a m2m through field with uniqueness constraint.

[mitchellrj]

If a field is made read_only by DRF automatically by virtue of being a relation with a through-class and the field is also made required automatically by virtue of being used in a uniqueness constraint, the read_only and required arguments clash due to ModelSerializer.include_extra_kwargs only checking for read_only in extra_kwargs.

[tomchristie]

Okay. Presumably the end result of that is that you'll always have a validation error for that field stating that: "this field is required", right?

[xordoquy]

You should be able to get rid of the constraint by override the contraint. I wrote a mail about this yesterday on the mailing list.

[tomchristie]

If anyone's able to search through the list and then link through to past discussion on this that'd help progress this issue.

[tomchristie]

Note to self that #2882 is not the same as this issue.
Retitled to make the narrow scope of this issue more prominent.

[philippeluickx]

Linked to #2848 ?

[xordoquy]

@philippeluickx looks like, thanks for pointing it.

[tomchristie]

Should now be resolved via #4192.