chore: make contributor's checklist pass on CPython 3.12 (#2199)

* chore(py312): fix docs build errors/warnings on CPython 3.12

* test(ws): add missing coverage on py312

* chore(mintest): add py312 to CI

* chore: add missing setuptools dep

* chore: leave mintest.yaml only for master merge CI after demonstration

.github/workflows/mintest.yaml

@@ -18,6 +18,7 @@ jobs:
           - "3.8"
           - "3.10"
           - "3.11"
+          - "3.12"
 
     steps:
       - name: Checkout repo
@@ -31,7 +32,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install -U tox
+          pip install -U setuptools tox wheel
           python --version
           pip --version
           tox --version

docs/conf.py

@@ -88,7 +88,7 @@
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 
-cfg = configparser.SafeConfigParser()
+cfg = configparser.ConfigParser()
 cfg.read('../setup.cfg')
 tag = cfg.get('egg_info', 'tag_build')
 

docs/ext/rfc.py

@@ -23,7 +23,7 @@
 import re
 
 
-RFC_PATTERN = re.compile('RFC (\d{4}), Section ([\d\.]+)')
+RFC_PATTERN = re.compile(r'RFC (\d{4}), Section ([\d\.]+)')
 
 
 def _render_section(section_number, rfc_number):

falcon/asgi/ws.py

@@ -530,12 +530,14 @@ class WebSocketOptions:
 
     __slots__ = ['error_close_code', 'max_receive_queue', 'media_handlers']
 
-    def __init__(self):
+    def __init__(self) -> None:
         try:
             import msgpack
         except ImportError:
             msgpack = None
 
+        bin_handler: media.BinaryBaseHandlerWS
+
         if msgpack:
             bin_handler = media.MessagePackHandlerWS()
         else:

falcon/media/handlers.py

@@ -6,6 +6,7 @@
 from falcon.constants import MEDIA_MULTIPART
 from falcon.constants import MEDIA_URLENCODED
 from falcon.constants import PYPY
+from falcon.media.base import BinaryBaseHandlerWS
 from falcon.media.json import JSONHandler
 from falcon.media.multipart import MultipartFormHandler
 from falcon.media.multipart import MultipartParseOptions
@@ -15,7 +16,7 @@
 from falcon.vendor import mimeparse
 
 
-class MissingDependencyHandler:
+class MissingDependencyHandler(BinaryBaseHandlerWS):
     """Placeholder handler that always raises an error.
 
     This handler is used by the framework for media types that require an

falcon/testing/helpers.py

@@ -402,6 +402,8 @@ class ASGIWebSocketSimulator:
             ``None`` if the connection has not been accepted.
     """
 
+    _DEFAULT_WAIT_READY_TIMEOUT = 5
+
     def __init__(self):
         self.__msgpack = None
 
@@ -435,7 +437,7 @@ def subprotocol(self) -> str:
     def headers(self) -> Iterable[Iterable[bytes]]:
         return self._accepted_headers
 
-    async def wait_ready(self, timeout: Optional[int] = 5):
+    async def wait_ready(self, timeout: Optional[int] = None):
         """Wait until the connection has been accepted or denied.
 
         This coroutine can be awaited in order to pause execution until the
@@ -447,16 +449,17 @@ async def wait_ready(self, timeout: Optional[int] = 5):
                 raising an error (default: ``5``).
         """
 
+        timeout = timeout or self._DEFAULT_WAIT_READY_TIMEOUT
+
         try:
             await asyncio.wait_for(self._event_handshake_complete.wait(), timeout)
         except asyncio.TimeoutError:
             msg = (
-                'Timed out after waiting {} seconds for '
-                'the WebSocket handshake to complete. Check the '
-                'on_websocket responder and '
-                'any middleware for any conditions that may be stalling the '
-                'request flow.'
-            ).format(timeout)
+                f'Timed out after waiting {timeout} seconds for the WebSocket '
+                f'handshake to complete. Check the on_websocket responder and '
+                f'any middleware for any conditions that may be stalling the '
+                f'request flow.'
+            )
             raise asyncio.TimeoutError(msg)
 
         self._require_accepted()

tests/asgi/test_ws.py

@@ -10,6 +10,7 @@
 from falcon import media, testing
 from falcon.asgi import App
 from falcon.asgi.ws import _WebSocketState as ServerWebSocketState
+from falcon.asgi.ws import WebSocket
 from falcon.asgi.ws import WebSocketOptions
 from falcon.testing.helpers import _WebSocketState as ClientWebSocketState
 
@@ -1088,6 +1089,34 @@ class Resource:
             event = await ws._emit()
 
 
+@pytest.mark.asyncio
+async def test_ws_responder_never_ready(conductor, monkeypatch):
+    async def noop_close(obj, code=None):
+        pass
+
+    class SleepyResource:
+        async def on_websocket(self, req, ws):
+            for i in range(10):
+                await asyncio.sleep(0.001)
+
+    conductor.app.add_route('/', SleepyResource())
+
+    # NOTE(vytas): It seems that it is hard to impossible to hit the second
+    #   `await ready_waiter` of the _WSContextManager on CPython 3.12 due to
+    #   different async code optimizations, so we mock away WebSocket.close.
+    monkeypatch.setattr(WebSocket, 'close', noop_close)
+
+    # NOTE(vytas): Shorten the timeout so that we do not wait for 5 seconds.
+    monkeypatch.setattr(
+        testing.ASGIWebSocketSimulator, '_DEFAULT_WAIT_READY_TIMEOUT', 0.5
+    )
+
+    async with conductor as c:
+        with pytest.raises(asyncio.TimeoutError):
+            async with c.simulate_ws():
+                pass
+
+
 @pytest.mark.skipif(msgpack, reason='test requires msgpack lib to be missing')
 def test_msgpack_missing():