Typechecked annotations (and droped support for python 3.5)

Also adds mypy to enforce typing

.github/workflows/tests.yml

@@ -14,7 +14,6 @@ jobs:
       fail-fast: false
       matrix:
         python-version:
-        - 3.5
         - 3.6
         - 3.7
         - 3.8

README.rst

@@ -96,7 +96,7 @@ file handles for incoming POST bodies).
 Dependencies
 ------------
 
-``asgiref`` requires Python 3.5 or higher.
+``asgiref`` requires Python 3.6 or higher.
 
 
 Contributing

asgiref/local.py

@@ -32,10 +32,10 @@ class Local:
 
     CLEANUP_INTERVAL = 60  # seconds
 
-    def __init__(self, thread_critical=False):
+    def __init__(self, thread_critical: bool = False) -> None:
         self._thread_critical = thread_critical
         self._thread_lock = threading.RLock()
-        self._context_refs = weakref.WeakSet()
+        self._context_refs: "weakref.WeakSet[object]" = weakref.WeakSet()
         # Random suffixes stop accidental reuse between different Locals,
         # though we try to force deletion as well.
         self._attr_name = "_asgiref_local_impl_%s_%s" % (

asgiref/sync.py

@@ -1,18 +1,18 @@
-import asyncio
 import asyncio.coroutines
 import functools
 import os
 import sys
 import threading
 import weakref
 from concurrent.futures import Future, ThreadPoolExecutor
+from typing import Dict
 
 from .current_thread_executor import CurrentThreadExecutor
 from .local import Local
 
-try:
-    import contextvars  # Python 3.7+ only.
-except ImportError:
+if sys.version_info >= (3, 7):
+    import contextvars
+else:
     contextvars = None
 
 
@@ -94,7 +94,7 @@ class AsyncToSync:
     """
 
     # Maps launched Tasks to the threads that launched them (for locals impl)
-    launch_map = {}
+    launch_map: "Dict[asyncio.Task[object], threading.Thread]" = {}
 
     # Keeps track of which CurrentThreadExecutor to use. This uses an asgiref
     # Local, not a threadlocal, so that tasks can work out what their parent used.
@@ -301,7 +301,7 @@ class SyncToAsync:
         )
 
     # Maps launched threads to the coroutines that spawned them
-    launch_map = {}
+    launch_map: "Dict[threading.Thread, asyncio.Task[object]]" = {}
 
     # Storage for main event loop references
     threadlocal = threading.local()
@@ -317,7 +317,9 @@ class SyncToAsync:
 
     # Maintaining a weak reference to the context ensures that thread pools are
     # erased once the context goes out of scope. This terminates the thread pool.
-    context_to_thread_executor = weakref.WeakKeyDictionary()
+    context_to_thread_executor: "weakref.WeakKeyDictionary[object, ThreadPoolExecutor]" = (
+        weakref.WeakKeyDictionary()
+    )
 
     def __init__(self, func, thread_sensitive=True):
         self.func = func

asgiref/timeout.py

@@ -9,9 +9,7 @@
 import asyncio
 import sys
 from types import TracebackType
-from typing import Any, Optional, Type  # noqa
-
-PY_37 = sys.version_info >= (3, 7)
+from typing import Any, Optional, Type
 
 
 class timeout:
@@ -115,14 +113,15 @@ def _cancel_task(self) -> None:
             self._cancelled = True
 
 
-def current_task(loop: asyncio.AbstractEventLoop) -> "asyncio.Task[Any]":
-    if PY_37:
-        task = asyncio.current_task(loop=loop)  # type: ignore
+def current_task(loop: asyncio.AbstractEventLoop) -> "Optional[asyncio.Task[Any]]":
+    if sys.version_info >= (3, 7):
+        task = asyncio.current_task(loop=loop)
     else:
         task = asyncio.Task.current_task(loop=loop)
     if task is None:
         # this should be removed, tokio must use register_task and family API
-        if hasattr(loop, "current_task"):
-            task = loop.current_task()  # type: ignore
+        fn = getattr(loop, "current_task", None)
+        if fn is not None:
+            task = fn()
 
     return task

docs/conf.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
+from typing import List, Dict
 #
 # ASGI documentation build configuration file, created by
 # sphinx-quickstart on Thu May 17 21:22:10 2018.
@@ -31,10 +32,10 @@
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = []
+extensions: List[str] = []
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = []
+templates_path: List[str] = []
 
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
@@ -120,7 +121,7 @@
 
 # -- Options for LaTeX output ---------------------------------------------
 
-latex_elements = {
+latex_elements: Dict[str, str] = {
     # The paper size ('letterpaper' or 'a4paper').
     #
     # 'papersize': 'letterpaper',

setup.cfg

@@ -16,7 +16,6 @@ classifiers =
     Programming Language :: Python
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: 3.5
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
@@ -28,7 +27,7 @@ project_urls =
     Changelog = https://github.com/django/asgiref/blob/master/CHANGELOG.txt
 
 [options]
-python_requires = >=3.5
+python_requires = >=3.6
 packages = find:
 include_package_data = true
 install_requires =
@@ -39,6 +38,7 @@ zip_safe = false
 tests =
     pytest
     pytest-asyncio
+    mypy>=0.800
 
 [tool:pytest]
 testpaths = tests
@@ -50,3 +50,63 @@ max-line-length = 119
 
 [isort]
 line_length = 119
+
+[mypy]
+warn_unused_ignores = True
+strict = True
+
+[mypy-asgiref.current_thread_executor]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-asgiref.local]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-asgiref.sync]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-asgiref.compatibility]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-asgiref.wsgi]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-asgiref.testing]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-asgiref.server]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-test_server]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-test_wsgi]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-test_testing]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-test_sync_contextvars]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-test_sync]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-test_local]
+disallow_untyped_defs = False
+check_untyped_defs = False
+
+[mypy-test_compatibility]
+disallow_untyped_defs = False
+check_untyped_defs = False

setup.py

@@ -1,3 +1,3 @@
-from setuptools import setup
+from setuptools import setup  # type: ignore[import]
 
 setup(name='asgiref')

tox.ini

@@ -1,13 +1,14 @@
 [tox]
 envlist =
-    py{35,36,37,38,39}
+    py{36,37,38,39}-{test,mypy}
     qa
 
 [testenv]
 usedevelop = true
 extras = tests
 commands =
-    pytest -v {posargs}
+    test: pytest -v {posargs}
+    mypy: mypy . {posargs}
 
 [testenv:qa]
 skip_install=true