Add typings (MagicStack#366)

* Add typings and mypy test case
* Update flake8
* Rename test class

Co-authored-by: Fantix King <[email protected]>

Author: bryanforbes

.flake8

@@ -1,6 +1,8 @@
 [flake8]
-filename = *.py,*.pyx,*.pxd,*.pxi
+filename = *.py,*.pyx,*.pxd,*.pxi,*.pyi
 ignore = E402,E731,D100,D101,D102,D103,D104,D105,W503,W504,E252
 exclude = .git,__pycache__,build,dist,.eggs,postgres,vendor
 
-per-file-ignores = *.pyx,*.pxd,*.pxi: E211, E222, E225, E226, E227, E999
+per-file-ignores =
+    *.pyx,*.pxd,*.pxi: E211, E222, E225, E226, E227, E999
+    *.pyi: F401, F403, F405, F811, E127, E128, E203, E266, E301, E302, E305, E501, E701, E704, E741, B303, W503, W504

.gitignore

@@ -32,3 +32,4 @@ uvloop/loop.*.pyd
 /.mypy_cache/
 /.vscode
 /.eggs
+/.venv*

MANIFEST.in

@@ -1,9 +1,9 @@
 recursive-include docs *.py *.rst
 recursive-include examples *.py
 recursive-include tests *.py *.pem
-recursive-include uvloop *.pyx *.pxd *.pxi *.py *.c *.h
+recursive-include uvloop *.pyx *.pxd *.pxi *.py *.c *.h *.pyi py.typed
 recursive-include vendor/libuv *
 recursive-exclude vendor/libuv/.git *
 recursive-exclude vendor/libuv/docs *
 recursive-exclude vendor/libuv/img *
-include LICENSE-MIT LICENSE-APACHE README.rst Makefile performance.png .flake8
+include LICENSE-MIT LICENSE-APACHE README.rst Makefile performance.png .flake8 mypy.ini

mypy.ini

@@ -0,0 +1,6 @@
+[mypy]
+incremental = True
+strict = True
+
+[mypy-uvloop._testbase]
+ignore_errors = True

setup.py

@@ -29,10 +29,11 @@
     # their combination breaks too often
     # (example breakage: https://gitlab.com/pycqa/flake8/issues/427)
     'aiohttp',
-    'flake8~=3.7.9',
+    'flake8~=3.8.4',
     'psutil',
-    'pycodestyle~=2.5.0',
-    'pyOpenSSL~=19.0.0'
+    'pycodestyle~=2.6.0',
+    'pyOpenSSL~=19.0.0',
+    'mypy>=0.800',
 ]
 
 # Dependencies required to build documentation.

tests/test_sourcecode.py

@@ -8,7 +8,7 @@ def find_uvloop_root():
     return os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 
 
-class TestFlake8(unittest.TestCase):
+class TestSourceCode(unittest.TestCase):
 
     def test_flake8(self):
         edgepath = find_uvloop_root()
@@ -33,3 +33,34 @@ def test_flake8(self):
                 output = ex.output.decode()
                 raise AssertionError(
                     'flake8 validation failed:\n{}'.format(output)) from None
+
+    def test_mypy(self):
+        edgepath = find_uvloop_root()
+        config_path = os.path.join(edgepath, 'mypy.ini')
+        if not os.path.exists(config_path):
+            raise RuntimeError('could not locate mypy.ini file')
+
+        try:
+            import mypy  # NoQA
+        except ImportError:
+            raise unittest.SkipTest('mypy moudule is missing')
+
+        try:
+            subprocess.run(
+                [
+                    sys.executable,
+                    '-m',
+                    'mypy',
+                    '--config-file',
+                    config_path,
+                    'uvloop'
+                ],
+                check=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+                cwd=edgepath
+            )
+        except subprocess.CalledProcessError as ex:
+            output = ex.output.decode()
+            raise AssertionError(
+                'mypy validation failed:\n{}'.format(output)) from None

uvloop/__init__.py

@@ -1,4 +1,5 @@
 import asyncio as __asyncio
+import typing as _typing
 
 from asyncio.events import BaseDefaultEventLoopPolicy as __BasePolicy
 
@@ -10,16 +11,16 @@
 __all__ = ('new_event_loop', 'install', 'EventLoopPolicy')
 
 
-class Loop(__BaseLoop, __asyncio.AbstractEventLoop):
+class Loop(__BaseLoop, __asyncio.AbstractEventLoop):  # type: ignore[misc]
     pass
 
 
-def new_event_loop():
+def new_event_loop() -> Loop:
     """Return a new event loop."""
     return Loop()
 
 
-def install():
+def install() -> None:
     """A helper function to install uvloop policy."""
     __asyncio.set_event_loop_policy(EventLoopPolicy())
 
@@ -36,5 +37,18 @@ class EventLoopPolicy(__BasePolicy):
     <uvloop.Loop running=False closed=False debug=False>
     """
 
-    def _loop_factory(self):
+    def _loop_factory(self) -> Loop:
         return new_event_loop()
+
+    if _typing.TYPE_CHECKING:
+        # EventLoopPolicy doesn't implement these, but since they are marked
+        # as abstract in typeshed, we have to put them in so mypy thinks
+        # the base methods are overridden. This is the same approach taken
+        # for the Windows event loop policy classes in typeshed.
+        def get_child_watcher(self) -> _typing.NoReturn:
+            ...
+
+        def set_child_watcher(
+            self, watcher: _typing.Any
+        ) -> _typing.NoReturn:
+            ...

uvloop/_noop.py

@@ -1,3 +1,3 @@
-def noop():
+def noop() -> None:
     """Empty function to invoke CPython ceval loop."""
     return