Fix behaviour of async PythonParser to match RedisParser as for issue #2349 (#2582)

* Allow data to drain from PythonParser after connection close.

* Add Changes

3 files changed, 12 insertions, 15 deletions

diff --git a/CHANGES b/CHANGES
index 3e4eba4..b0744c6 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,4 @@
+    * Allow data to drain from async PythonParser when reading during a disconnect()
     * Use asyncio.timeout() instead of async_timeout.timeout() for python >= 3.11 (#2602)
     * Add test and fix async HiredisParser when reading during a disconnect() (#2349)
     * Use hiredis-py pack_command if available.
diff --git a/redis/asyncio/connection.py b/redis/asyncio/connection.py
index 93db37e..057067a 100644
--- a/redis/asyncio/connection.py
+++ b/redis/asyncio/connection.py
@@ -146,7 +146,7 @@ ExceptionMappingT = Mapping[str, Union[Type[Exception], Mapping[str, Type[Except
 class BaseParser:
     """Plain Python parsing class"""
 
-    __slots__ = "_stream", "_read_size"
+    __slots__ = "_stream", "_read_size", "_connected"
 
     EXCEPTION_CLASSES: ExceptionMappingT = {
         "ERR": {
@@ -177,6 +177,7 @@ 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:
@@ -213,7 +214,7 @@ class BaseParser:
 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)
@@ -231,21 +232,19 @@ class PythonParser(BaseParser):
         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(0):
                 return await self._stream.read(1)
@@ -253,6 +252,8 @@ class PythonParser(BaseParser):
             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)
@@ -266,8 +267,6 @@ class PythonParser(BaseParser):
     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:]
@@ -354,14 +353,13 @@ class PythonParser(BaseParser):
 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
diff --git a/tests/test_asyncio/test_connection.py b/tests/test_asyncio/test_connection.py
index 1851ca9..e2d77fc 100644
--- a/tests/test_asyncio/test_connection.py
+++ b/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")