Fix ConnectionPool state after async cancellation

grynko · grynko · commit 49a585510613 · 2024-12-18T17:46:44.000+02:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [Unreleased]
+
+- Fix `ConnectionPool` state after async cancellation.
+
+
 ## Version 1.0.7 (November 15th, 2024)
 
 - Support `proxy=…` configuration on `ConnectionPool()`. (#974)
diff --git a/httpcore/_async/connection.py b/httpcore/_async/connection.py
@@ -172,6 +172,9 @@ async def aclose(self) -> None:
             async with Trace("close", logger, None, {}):
                 await self._connection.aclose()
 
+    def is_connected(self) -> bool:
+        return not (self._connection is None or self._connection.is_closed())
+
     def is_available(self) -> bool:
         if self._connection is None:
             # If HTTP/2 support is enabled, and the resulting connection could
diff --git a/httpcore/_async/connection_pool.py b/httpcore/_async/connection_pool.py
@@ -278,13 +278,17 @@ def _assign_requests_to_connections(self) -> list[AsyncConnectionInterface]:
         those connections to be handled seperately.
         """
         closing_connections = []
+        request_connections = {request.connection for request in self._requests}
 
         # First we handle cleaning up any connections that are closed,
         # have expired their keep-alive, or surplus idle connections.
         for connection in list(self._connections):
             if connection.is_closed():
                 # log: "removing closed connection"
                 self._connections.remove(connection)
+            elif not (connection.is_connected() or connection in request_connections):
+                # log: "removing garbage connection"
+                self._connections.remove(connection)
             elif connection.has_expired():
                 # log: "closing expired connection"
                 self._connections.remove(connection)
diff --git a/httpcore/_async/http11.py b/httpcore/_async/http11.py
@@ -264,6 +264,9 @@ async def aclose(self) -> None:
     def can_handle_request(self, origin: Origin) -> bool:
         return origin == self._origin
 
+    def is_connected(self) -> bool:
+        return not self.is_closed()
+
     def is_available(self) -> bool:
         # Note that HTTP/1.1 connections in the "NEW" state are not treated as
         # being "available". The control flow which created the connection will
diff --git a/httpcore/_async/http2.py b/httpcore/_async/http2.py
@@ -499,6 +499,9 @@ async def _wait_for_outgoing_flow(self, request: Request, stream_id: int) -> int
     def can_handle_request(self, origin: Origin) -> bool:
         return origin == self._origin
 
+    def is_connected(self) -> bool:
+        return not self.is_closed()
+
     def is_available(self) -> bool:
         return (
             self._state != HTTPConnectionState.CLOSED
diff --git a/httpcore/_async/http_proxy.py b/httpcore/_async/http_proxy.py
@@ -214,6 +214,9 @@ async def aclose(self) -> None:
     def info(self) -> str:
         return self._connection.info()
 
+    def is_connected(self) -> bool:
+        return self._connection.is_connected()
+
     def is_available(self) -> bool:
         return self._connection.is_available()
 
@@ -351,6 +354,9 @@ async def aclose(self) -> None:
     def info(self) -> str:
         return self._connection.info()
 
+    def is_connected(self) -> bool:
+        return self._connection.is_connected()
+
     def is_available(self) -> bool:
         return self._connection.is_available()
 
diff --git a/httpcore/_async/interfaces.py b/httpcore/_async/interfaces.py
@@ -94,6 +94,14 @@ def info(self) -> str:
     def can_handle_request(self, origin: Origin) -> bool:
         raise NotImplementedError()  # pragma: nocover
 
+    def is_connected(self) -> bool:
+        """
+        Return `True` if the connection is open.
+
+        Beware that for some implementations `is_connected() != not is_closed()`.
+        """
+        raise NotImplementedError()  # pragma: nocover
+
     def is_available(self) -> bool:
         """
         Return `True` if the connection is currently able to accept an
diff --git a/httpcore/_async/socks_proxy.py b/httpcore/_async/socks_proxy.py
@@ -305,6 +305,9 @@ async def aclose(self) -> None:
         if self._connection is not None:
             await self._connection.aclose()
 
+    def is_connected(self) -> bool:
+        return not (self._connection is None or self._connection.is_closed())
+
     def is_available(self) -> bool:
         if self._connection is None:  # pragma: nocover
             # If HTTP/2 support is enabled, and the resulting connection could
diff --git a/httpcore/_sync/connection.py b/httpcore/_sync/connection.py
@@ -172,6 +172,9 @@ def close(self) -> None:
             with Trace("close", logger, None, {}):
                 self._connection.close()
 
+    def is_connected(self) -> bool:
+        return not (self._connection is None or self._connection.is_closed())
+
     def is_available(self) -> bool:
         if self._connection is None:
             # If HTTP/2 support is enabled, and the resulting connection could
diff --git a/httpcore/_sync/connection_pool.py b/httpcore/_sync/connection_pool.py
@@ -278,13 +278,17 @@ def _assign_requests_to_connections(self) -> list[ConnectionInterface]:
         those connections to be handled seperately.
         """
         closing_connections = []
+        request_connections = {request.connection for request in self._requests}
 
         # First we handle cleaning up any connections that are closed,
         # have expired their keep-alive, or surplus idle connections.
         for connection in list(self._connections):
             if connection.is_closed():
                 # log: "removing closed connection"
                 self._connections.remove(connection)
+            elif not (connection.is_connected() or connection in request_connections):
+                # log: "removing garbage connection"
+                self._connections.remove(connection)
             elif connection.has_expired():
                 # log: "closing expired connection"
                 self._connections.remove(connection)
diff --git a/httpcore/_sync/http11.py b/httpcore/_sync/http11.py
@@ -264,6 +264,9 @@ def close(self) -> None:
     def can_handle_request(self, origin: Origin) -> bool:
         return origin == self._origin
 
+    def is_connected(self) -> bool:
+        return not self.is_closed()
+
     def is_available(self) -> bool:
         # Note that HTTP/1.1 connections in the "NEW" state are not treated as
         # being "available". The control flow which created the connection will
diff --git a/httpcore/_sync/http2.py b/httpcore/_sync/http2.py
@@ -499,6 +499,9 @@ def _wait_for_outgoing_flow(self, request: Request, stream_id: int) -> int:
     def can_handle_request(self, origin: Origin) -> bool:
         return origin == self._origin
 
+    def is_connected(self) -> bool:
+        return not self.is_closed()
+
     def is_available(self) -> bool:
         return (
             self._state != HTTPConnectionState.CLOSED
diff --git a/httpcore/_sync/http_proxy.py b/httpcore/_sync/http_proxy.py
@@ -214,6 +214,9 @@ def close(self) -> None:
     def info(self) -> str:
         return self._connection.info()
 
+    def is_connected(self) -> bool:
+        return not self._connection.is_closed()
+
     def is_available(self) -> bool:
         return self._connection.is_available()
 
@@ -351,6 +354,9 @@ def close(self) -> None:
     def info(self) -> str:
         return self._connection.info()
 
+    def is_connected(self) -> bool:
+        return not self._connection.is_closed()
+
     def is_available(self) -> bool:
         return self._connection.is_available()
 
diff --git a/httpcore/_sync/interfaces.py b/httpcore/_sync/interfaces.py
@@ -94,6 +94,14 @@ def info(self) -> str:
     def can_handle_request(self, origin: Origin) -> bool:
         raise NotImplementedError()  # pragma: nocover
 
+    def is_connected(self) -> bool:
+        """
+        Return `True` if the connection is established.
+
+        Beware that for some implementations `is_connected() != not is_closed()`.
+        """
+        raise NotImplementedError()  # pragma: nocover
+
     def is_available(self) -> bool:
         """
         Return `True` if the connection is currently able to accept an
diff --git a/httpcore/_sync/socks_proxy.py b/httpcore/_sync/socks_proxy.py
@@ -305,6 +305,9 @@ def close(self) -> None:
         if self._connection is not None:
             self._connection.close()
 
+    def is_connected(self) -> bool:
+        return not (self._connection is None or self._connection.is_closed())
+
     def is_available(self) -> bool:
         if self._connection is None:  # pragma: nocover
             # If HTTP/2 support is enabled, and the resulting connection could
diff --git a/tests/_async/test_connection.py b/tests/_async/test_connection.py
@@ -36,6 +36,7 @@ async def test_http_connection():
         origin=origin, network_backend=network_backend, keepalive_expiry=5.0
     ) as conn:
         assert not conn.is_idle()
+        assert not conn.is_connected()
         assert not conn.is_closed()
         assert not conn.is_available()
         assert not conn.has_expired()
@@ -52,6 +53,7 @@ async def test_http_connection():
         assert response.content == b"Hello, world!"
 
         assert conn.is_idle()
+        assert conn.is_connected()
         assert not conn.is_closed()
         assert conn.is_available()
         assert not conn.has_expired()
diff --git a/tests/_async/test_http11.py b/tests/_async/test_http11.py
@@ -23,6 +23,7 @@ async def test_http11_connection():
         assert response.content == b"Hello, world!"
 
         assert conn.is_idle()
+        assert conn.is_connected()
         assert not conn.is_closed()
         assert conn.is_available()
         assert not conn.has_expired()
diff --git a/tests/_async/test_http2.py b/tests/_async/test_http2.py
@@ -35,6 +35,7 @@ async def test_http2_connection():
 
         assert conn.is_idle()
         assert conn.is_available()
+        assert conn.is_connected()
         assert not conn.is_closed()
         assert not conn.has_expired()
         assert (
diff --git a/tests/_sync/test_connection.py b/tests/_sync/test_connection.py
@@ -36,6 +36,7 @@ def test_http_connection():
         origin=origin, network_backend=network_backend, keepalive_expiry=5.0
     ) as conn:
         assert not conn.is_idle()
+        assert not conn.is_connected()
         assert not conn.is_closed()
         assert not conn.is_available()
         assert not conn.has_expired()
@@ -52,6 +53,7 @@ def test_http_connection():
         assert response.content == b"Hello, world!"
 
         assert conn.is_idle()
+        assert conn.is_connected()
         assert not conn.is_closed()
         assert conn.is_available()
         assert not conn.has_expired()
diff --git a/tests/_sync/test_http11.py b/tests/_sync/test_http11.py
@@ -23,6 +23,7 @@ def test_http11_connection():
         assert response.content == b"Hello, world!"
 
         assert conn.is_idle()
+        assert conn.is_connected()
         assert not conn.is_closed()
         assert conn.is_available()
         assert not conn.has_expired()
diff --git a/tests/_sync/test_http2.py b/tests/_sync/test_http2.py
@@ -35,6 +35,7 @@ def test_http2_connection():
 
         assert conn.is_idle()
         assert conn.is_available()
+        assert conn.is_connected()
         assert not conn.is_closed()
         assert not conn.has_expired()
         assert (
diff --git a/tests/test_cancellations.py b/tests/test_cancellations.py
@@ -1,4 +1,5 @@
 import typing
+from unittest.mock import patch
 
 import anyio
 import hpack
@@ -135,6 +136,25 @@ async def test_connection_pool_timeout_during_response():
         assert not pool.connections
 
 
+@pytest.mark.anyio
+async def test_connection_pool_cancellation_during_waiting_for_connection():
+    """
+    A cancellation of ongoing request waiting for a connection should leave
+    the pool in a consistent state.
+
+    In this case, that means the connection will become closed, and no
+    longer remain in the pool.
+    """
+    async def wait_for_connection(self, *args, **kwargs):
+        await anyio.sleep(999)
+
+    with patch("httpcore._async.connection_pool.AsyncPoolRequest.wait_for_connection", new=wait_for_connection):
+        async with httpcore.AsyncConnectionPool() as pool:
+            with anyio.move_on_after(0.01):
+                await pool.request("GET", "http://example.com")
+            assert not pool.connections
+
+
 @pytest.mark.anyio
 async def test_h11_timeout_during_request():
     """
