Fix for Unhandled exception related to self.host with unix socket (#2520)

* Fix for Unhandled exception related to self.host with unix socket

* Added change to the CHANGES file

* fix linter error

* Reformatted connection.py file

Author: winmorre

CHANGES

@@ -31,6 +31,7 @@
     * Enable Lock for asyncio cluster mode
     * Fix Sentinel.execute_command doesn't execute across the entire sentinel cluster bug (#2458)
     * Added a replacement for the default cluster node in the event of failure (#2463)
+    * Fix for Unhandled exception related to self.host with unix socket (#2496)
 
 * 4.1.3 (Feb 8, 2022)
     * Fix flushdb and flushall (#1926)

redis/connection.py

@@ -664,20 +664,31 @@ def _connect(self):
             raise err
         raise OSError("socket.getaddrinfo returned an empty list")
 
+    def _host_error(self):
+        try:
+            host_error = f"{self.host}:{self.port}"
+        except AttributeError:
+            host_error = "connection"
+
+        return host_error
+
     def _error_message(self, exception):
         # args for socket.error can either be (errno, "message")
         # or just "message"
+
+        host_error = self._host_error()
+
         if len(exception.args) == 1:
             try:
-                return f"Error connecting to {self.host}:{self.port}. \
+                return f"Error connecting to {host_error}. \
                         {exception.args[0]}."
             except AttributeError:
                 return f"Connection Error: {exception.args[0]}"
         else:
             try:
                 return (
                     f"Error {exception.args[0]} connecting to "
-                    f"{self.host}:{self.port}. {exception.args[1]}."
+                    f"{host_error}. {exception.args[1]}."
                 )
             except AttributeError:
                 return f"Connection Error: {exception.args[0]}"
@@ -793,29 +804,30 @@ def can_read(self, timeout=0):
         sock = self._sock
         if not sock:
             self.connect()
+
+        host_error = self._host_error()
+
         try:
             return self._parser.can_read(timeout)
         except OSError as e:
             self.disconnect()
-            raise ConnectionError(
-                f"Error while reading from {self.host}:{self.port}: {e.args}"
-            )
+            raise ConnectionError(f"Error while reading from {host_error}: {e.args}")
 
     def read_response(self, disable_decoding=False):
         """Read the response from a previously sent command"""
-        try:
-            hosterr = f"{self.host}:{self.port}"
-        except AttributeError:
-            hosterr = "connection"
+
+        host_error = self._host_error()
 
         try:
             response = self._parser.read_response(disable_decoding=disable_decoding)
         except socket.timeout:
             self.disconnect()
-            raise TimeoutError(f"Timeout reading from {hosterr}")
+            raise TimeoutError(f"Timeout reading from {host_error}")
         except OSError as e:
             self.disconnect()
-            raise ConnectionError(f"Error while reading from {hosterr}" f" : {e.args}")
+            raise ConnectionError(
+                f"Error while reading from {host_error}" f" : {e.args}"
+            )
         except Exception:
             self.disconnect()
             raise