Add typings

[bryanforbes]

This PR adds typings for use with type checkers like mypy. Overall, this was fairly easy but two errors have to be suppressed with a # type: ignore comment:

• remove_signal_handler() returns a bool and typeshed has this method returning None in AbstractEventLoop. This seems to be an error in typeshed since the docs state it should return a bool.
• create_connection() in Python 3.8+ accepts two new arguments (happy_eyeballs_delay and interleave) and since uvloop.Loop.create_connection() doesn't allow those arguments, the two methods are incompatible. This may be unavoidable.

References #358

[1st1]

I'm curious why we need this as opposed to simply using asyncio.AbstractServer?

[bryanforbes]

asyncio.AbstractServer is defined as follows in typeshed:

class AbstractServer:
    sockets: Optional[List[socket]]
    def close(self) -> None: ...
    if sys.version_info >= (3, 7):
        async def __aenter__(self: _T) -> _T: ...
        async def __aexit__(self, *exc: Any) -> None: ...
        def get_loop(self) -> AbstractEventLoop: ...
        def is_serving(self) -> bool: ...
        async def start_serving(self) -> None: ...
        async def serve_forever(self) -> None: ...
    async def wait_closed(self) -> None: ...

Since uvloop works on Python 3.5+ and Server defines those methods for all versions, asyncio.AbstractServer will be wrong for uvloop on Python 3.5 and 3.6.

[1st1]

I'll be dropping support for 3.5 and 3.6. 3.5 is no longer supported by Python core devs; 3.6 is in security fixes only mode. And with 3.9 now out, uvloop will be 3.7+ only in its next release, supporting three Python versions: 3.7, 3.8, and 3.9.

[bryanforbes]

That's good to know! I'll go back over this PR with that in mind.

[bryanforbes]

One thing to note: I think we'll still need _Server because AbstractServer.sockets is Optional[List[Socket]] and Server.sockets is List[Socket].

[1st1]

I think we should stick to AbstractServer typing here too. That makes it easy for us to fix our Server.sockets property to follow the spec.

[bryanforbes]

Some of these others I added while I was navigating the source. I'll make sure I validate all of these are needed when I go over this again.

[1st1]

Yes, thanks. And we can always fix uvloop code that doesn't conform to asyncio APIs.

[bryanforbes]

Sorry that it's taken so long to get back to this. I've updated the PR based on your feedback and rebased on master. Unfortunately, the PR checks are failing prematurely.

[1st1]

@fantix We can probably merge this one too, please review.

[bryanforbes]

I can rebase this on master if it would make it easier to review. Just let me know.

[fantix]

@bryanforbes Yes, please! Thank you! Never mind, it's done 😃

[bryanforbes]

I have a couple of small edits to make before you merge

[fantix]

LGTM! I'll be waiting for your edits.

[bryanforbes]

@fantix I committed and pushed the edits. Let me know if you have questions about them. One thing to note: the two things I pointed out in the description of this PR are still issues. Once those methods are changed, the # type: ignore[misc] can be removed from __init__.py.

[fantix]

Once those methods are changed, the # type: ignore[misc] can be removed from __init__.py.

Sounds good 👍

[1st1]

Thanks @bryanforbes!

[bryanforbes]

Not a problem! If you ever have any typing questions, feel free to reach out to me.

[1st1]

@bryanforbes thanks! If you have time please take a look at MagicStack/immutables#54 -- another our package.