Distinct from any clear_submsg(), this clears the message contents and doesn't affect presence on parent (and also allows for clearing owned messages which don't exist as a field to be cleared).
PiperOrigin-RevId: 656453234
We modify set_<repeated_field> to accept the IntoProxied type as the value and move the value (avoid copying) whenever possible.
For UPB:
- We fuse the arena of Repeated<T> with the parent message arena.
- We use upb_Message_SetBaseField to set the upb_Array contained in the Repeated<T>.
For C++:
- We generate an additional setter thunk that moves the value.
- The move assignment operator of RepeatedField/RepeatedPtrField is specialized. In order to adhere to the layering check we need to add '#include' statements for all .proto imports to the generated thunks.pb.cc.
PiperOrigin-RevId: 631010333