Allow data to drain from PythonParser after connection close.

Author: kristjanvalur

redis/asyncio/connection.py

@@ -141,7 +141,7 @@ def decode(self, value: EncodableT, force=False) -> EncodableT:
 class BaseParser:
     """Plain Python parsing class"""
 
-    __slots__ = "_stream", "_read_size"
+    __slots__ = "_stream", "_read_size", "_connected"
 
     EXCEPTION_CLASSES: ExceptionMappingT = {
         "ERR": {
@@ -172,6 +172,7 @@ class BaseParser:
     def __init__(self, socket_read_size: int):
         self._stream: Optional[asyncio.StreamReader] = None
         self._read_size = socket_read_size
+        self._connected = False
 
     def __del__(self):
         try:
@@ -208,7 +209,7 @@ async def read_response(
 class PythonParser(BaseParser):
     """Plain Python parsing class"""
 
-    __slots__ = BaseParser.__slots__ + ("encoder", "_buffer", "_pos", "_chunks")
+    __slots__ = ("encoder", "_buffer", "_pos", "_chunks")
 
     def __init__(self, socket_read_size: int):
         super().__init__(socket_read_size)
@@ -226,28 +227,28 @@ def on_connect(self, connection: "Connection"):
         self._stream = connection._reader
         if self._stream is None:
             raise RedisError("Buffer is closed.")
-
         self.encoder = connection.encoder
+        self._clear()
+        self._connected = True
 
     def on_disconnect(self):
         """Called when the stream disconnects"""
-        if self._stream is not None:
-            self._stream = None
-        self.encoder = None
-        self._clear()
+        self._connected = False
 
     async def can_read_destructive(self) -> bool:
+        if not self._connected:
+            raise RedisError("Buffer is closed.")
         if self._buffer:
             return True
-        if self._stream is None:
-            raise RedisError("Buffer is closed.")
         try:
             async with async_timeout.timeout(0):
                 return await self._stream.read(1)
         except asyncio.TimeoutError:
             return False
 
     async def read_response(self, disable_decoding: bool = False):
+        if not self._connected:
+            raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
         if self._chunks:
             # augment parsing buffer with previously read data
             self._buffer += b"".join(self._chunks)
@@ -261,8 +262,6 @@ async def read_response(self, disable_decoding: bool = False):
     async def _read_response(
         self, disable_decoding: bool = False
     ) -> Union[EncodableT, ResponseError, None]:
-        if not self._stream or not self.encoder:
-            raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
         raw = await self._readline()
         response: Any
         byte, response = raw[:1], raw[1:]
@@ -350,14 +349,13 @@ async def _readline(self) -> bytes:
 class HiredisParser(BaseParser):
     """Parser class for connections using Hiredis"""
 
-    __slots__ = BaseParser.__slots__ + ("_reader", "_connected")
+    __slots__ = ("_reader",)
 
     def __init__(self, socket_read_size: int):
         if not HIREDIS_AVAILABLE:
             raise RedisError("Hiredis is not available.")
         super().__init__(socket_read_size=socket_read_size)
         self._reader: Optional[hiredis.Reader] = None
-        self._connected: bool = False
 
     def on_connect(self, connection: "Connection"):
         self._stream = connection._reader

tests/test_asyncio/test_connection.py

@@ -211,8 +211,6 @@ async def test_connection_disconect_race(parser_class):
     This test verifies that a read in progress can finish even
     if the `disconnect()` method is called.
     """
-    if parser_class == PythonParser:
-        pytest.xfail("doesn't work yet with PythonParser")
     if parser_class == HiredisParser and not HIREDIS_AVAILABLE:
         pytest.skip("Hiredis not available")