This PR ensures that even if a type has multiple annotations, we can
still detect the `BaseChannel` subclasses attached.
```py
class State(TypedDict):
# recognized as EphemeralValue(int)
foo: Annotated[int, EphemeralValue]
# now recognized as EphemeralValue(int)
bar: Annotated[int, EphemeralValue, OtherMetadata]
# now recognized as EphemeralValue(int)
baz: Annotated[int, SomeMetadata, EphemeralValue, OtherMetadata]
```
- Both have been deprecated long ago, have not been present in docs for quite a while
- Removing these lets us delete some code paths that were dedicated to this, easing work on distributed runner
Currently we ignore the input schema in the branch and instead use the
input schema from the previous node (or overall graph schema)
This change makes the input schema to branches respected. This means
that if you try to pass extra keys and they're NOT in the input schema,
you will receive an error. If you don't provide an annotation in the
router, it will fall back to the previous node's input schema / full
graph state schema
Alternative solution is to just ignore the input schema in the router
altogether (including ignoring the schema from previous node / full
graph), but personally I find it more confusing.
---------
Co-authored-by: Nuno Campos <nuno@langchain.dev>
- This more closely remembers the environment they're used in, so it's what we should be testing
- Remove unnecessary pytest-asyncio dependency, use anyio pytest plugin instead
- Convert remaining async tests using only memory checkpointer to use all existing ones
