Add typings

Add typings to the project and check the project using mypy.
`PostgresMessage` and `PoolConnectionProxy` were broken out into their
own files to make it easier to add typing via stub (pyi) files. Since
they are metaclasses which generate dynamic objects, we can't type them
directly in their python module.

Author: bryanforbes

.flake8

@@ -1,3 +1,5 @@
 [flake8]
+select = C90,E,F,W,Y0
 ignore = E402,E731,W503,W504,E252
-exclude = .git,__pycache__,build,dist,.eggs,.github,.local,.venv,.tox
+exclude = .git,__pycache__,build,dist,.eggs,.github,.local,.venv*,.tox
+per-file-ignores = *.pyi: F401, F403, F405, F811, E127, E128, E203, E266, E301, E302, E305, E501, E701, E704, E741, B303, W503, W504

.gitignore

@@ -34,3 +34,6 @@ docs/_build
 /.eggs
 /.vscode
 /.mypy_cache
+/.venv*
+/.tox
+/.vim

.gitmodules

@@ -1,3 +1,3 @@
 [submodule "asyncpg/pgproto"]
 	path = asyncpg/pgproto
-	url = https://github.com/MagicStack/py-pgproto.git
+	url = https://github.com/bryanforbes/py-pgproto.git

MANIFEST.in

@@ -1,5 +1,6 @@
 recursive-include docs *.py *.rst Makefile *.css
 recursive-include examples *.py
 recursive-include tests *.py *.pem
-recursive-include asyncpg *.pyx *.pxd *.pxi *.py *.c *.h
+recursive-include asyncpg *.pyx *.pxd *.pxi *.py *.pyi *.c *.h
 include LICENSE README.rst Makefile performance.png .flake8
+include asyncpg/py.typed

asyncpg/__init__.py

@@ -4,16 +4,17 @@
 # This module is part of asyncpg and is released under
 # the Apache 2.0 License: http://www.apache.org/licenses/LICENSE-2.0
 
+from __future__ import annotations
 
 from .connection import connect, Connection  # NOQA
 from .exceptions import *  # NOQA
 from .pool import create_pool, Pool  # NOQA
 from .protocol import Record  # NOQA
 from .types import *  # NOQA
 
-
+from . import exceptions
 from ._version import __version__  # NOQA
 
 
-__all__ = ('connect', 'create_pool', 'Pool', 'Record', 'Connection')
+__all__ = ['connect', 'create_pool', 'Pool', 'Record', 'Connection']
 __all__ += exceptions.__all__ # NOQA

asyncpg/_asyncio_compat.py

@@ -4,18 +4,28 @@
 #
 # SPDX-License-Identifier: PSF-2.0
 
+from __future__ import annotations
 
 import asyncio
 import functools
 import sys
+import typing
+
+if typing.TYPE_CHECKING:
+    from . import compat
 
 if sys.version_info < (3, 11):
     from async_timeout import timeout as timeout_ctx
 else:
     from asyncio import timeout as timeout_ctx
 
 
-async def wait_for(fut, timeout):
+_T = typing.TypeVar('_T')
+
+
+async def wait_for(
+    fut: compat.Awaitable[_T], timeout: float | None
+) -> _T:
     """Wait for the single Future or coroutine to complete, with timeout.
 
     Coroutine will be wrapped in Task.
@@ -65,7 +75,7 @@ async def wait_for(fut, timeout):
         return await fut
 
 
-async def _cancel_and_wait(fut):
+async def _cancel_and_wait(fut: asyncio.Future[_T]) -> None:
     """Cancel the *fut* future or task and wait until it completes."""
 
     loop = asyncio.get_running_loop()
@@ -82,6 +92,6 @@ async def _cancel_and_wait(fut):
         fut.remove_done_callback(cb)
 
 
-def _release_waiter(waiter, *args):
+def _release_waiter(waiter: asyncio.Future[typing.Any], *args: object) -> None:
     if not waiter.done():
         waiter.set_result(None)

asyncpg/_version.py

@@ -10,4 +10,8 @@
 # supported platforms, publish the packages on PyPI, merge the PR
 # to the target branch, create a Git tag pointing to the commit.
 
-__version__ = '0.30.0.dev0'
+from __future__ import annotations
+
+import typing
+
+__version__: typing.Final = '0.30.0.dev0'