[vyhuholl]

Description

Part of #3202.

Every specific overload of RedisRegistrator.subscriber() / .publisher() and of the FastAPI RedisRouter gave its destination a ... default. A call that names no destination matched the first overload:

broker = RedisBroker()

broker.subscriber()  # typed as ChannelSubscriber
broker.publisher()   # typed as StreamPublisher
# both raise at runtime:
# faststream.exceptions.SetupError: You have to specify `channel`, `list` or `stream`

pyrefly reports this as inconsistent-overload-default at redis/broker/registrator.py:49, 371 and redis/fastapi/fastapi.py:391, 724: the implementation defaults the destination to None, and the overload types don't admit it. The overloads lied about what may be omitted. The None default itself is live, since list= and stream= are passed without a channel.

Fix

• The destination an overload dispatches on is required there: channel in the channel overloads, list and stream in theirs.
• RedisRegistrator's catch-all overload for destinations known only at runtime (str | None) is split in three, one per destination. subscriber() and publisher() with no destination now match no overload, while broker.subscriber(stream=maybe_name) still resolves to LogicSubscriber. The FastAPI router never had a catch-all and doesn't get one.
• In the concurrent overloads max_workers: int = ... becomes max_workers: int. Once the destination was required, mypy reported the concurrent list and stream overloads as overlapping the plain ones (overload-overlap), because they too claimed max_workers could be left out.
• The FastAPI router's publisher() takes list and stream positionally, and a required parameter can't follow a defaulted positional one. Its list and stream overloads make them keyword-only, as RedisRegistrator.publisher() already does. Its first overload now carries # type: ignore[override], like the Kafka router's: the abstract StreamRouter.publisher(self) takes no arguments, and no overload accepts that call any more. pyrefly counts this as one new bad-override, the same finding the Kafka and Confluent routers already have.

No runtime change. The type checker now rejects calls with no destination, which always raised, and positional list / stream on the FastAPI router's publisher (router.publisher(None, "name")), which still works at runtime.

The other brokers keep their batch: Literal[True] = ..., max_workers: int = ... and no_confirm: Literal[True] = ... defaults. An earlier overload catches the call that omits them, so there the default never selects the overload.

Tests

In tests/mypy/redis.py:

• check_destination_is_required calls subscriber() and publisher() with no destination on RedisBroker, RedisRouter and the FastAPI RedisRouter, under # type: ignore[call-overload]. With faststream/ reverted, mypy fails it with two unused-ignore errors.
• check_runtime_destination_type pins that a str | None channel, list or stream still resolves to LogicSubscriber / LogicPublisher, so splitting the catch-all dropped nothing.

Checked

• just mypy (1883 files), just pyright and just pyrefly are clean, just linter passes.
• pyrefly check faststream: the four inconsistent-overload-default findings are gone; the bad-override above is the only new one.
• tests/brokers/redis/test_misconfigure.py, test_fastapi.py, test_router.py and test_option_surface.py pass in memory (65 tests).

Type of change

• Bug fix (a non-breaking change that resolves an issue)

Checklist

• My code adheres to the style guidelines of this project (just lint shows no errors)
• I have conducted a self-review of my own code
• My changes do not generate any new warnings
• I have added tests to validate the effectiveness of my fix or the functionality of my new feature
• just mypy, just pyright and just pyrefly pass