add PubSubError to better report disallowed command when using pub/sub

4 files changed, 13 insertions, 6 deletions

diff --git a/redis/__init__.py b/redis/__init__.py
index 499f658..c7d2460 100644
--- a/redis/__init__.py
+++ b/redis/__init__.py
@@ -5,6 +5,7 @@ from redis.exceptions import (
     ConnectionError,
     DataError,
     InvalidResponse,
+    PubSubError,
     RedisError,
     ResponseError,
     )
@@ -15,5 +16,5 @@ __version__ = '2.2.3'
 __all__ = [
     'Redis', 'ConnectionPool',
     'RedisError', 'ConnectionError', 'ResponseError', 'AuthenticationError',
-    'InvalidResponse', 'DataError',
+    'InvalidResponse', 'DataError', 'PubSubError',
     ]
diff --git a/redis/client.py b/redis/client.py
index 7b1c1ae..57ea0f0 100644
--- a/redis/client.py
+++ b/redis/client.py
@@ -8,6 +8,7 @@ from redis.exceptions import (
     AuthenticationError,
     ConnectionError,
     DataError,
+    PubSubError,
     RedisError,
     ResponseError,
     WatchError,
@@ -229,8 +230,8 @@ class Redis(threading.local):
     def _execute_command(self, command_name, command, **options):
         subscription_command = command_name in self.SUBSCRIPTION_COMMANDS
         if self.subscribed and not subscription_command:
-            raise RedisError("Cannot issue commands other than SUBSCRIBE and "
-                "UNSUBSCRIBE while channels are open")
+            raise PubSubError("Cannot issue commands other than SUBSCRIBE and "
+                              "UNSUBSCRIBE while channels are open")
         try:
             self.connection.send(command, self)
             if subscription_command:
@@ -319,7 +320,7 @@ class Redis(threading.local):
     def shutdown(self):
         "Shutdown the server"
         if self.subscribed:
-            raise RedisError("Can't call 'shutdown' from a pipeline'")
+            raise PubSubError("Can't call 'shutdown' when 'subscribed'")
         try:
             self.execute_command('SHUTDOWN')
         except ConnectionError:
@@ -610,7 +611,7 @@ class Redis(threading.local):
         Watches the values at keys ``names``, or None if the key doesn't exist
         """
         if self.subscribed:
-            raise RedisError("Can't call 'watch' from a pipeline'")
+            raise PubSubError("Can't call 'watch' when 'subscribed'")
 
         return self.execute_command('WATCH', *names)
 
@@ -619,7 +620,7 @@ class Redis(threading.local):
         Unwatches the value at key ``name``, or None of the key doesn't exist
         """
         if self.subscribed:
-            raise RedisError("Can't call 'unwatch' from a pipeline'")
+            raise PubSubError("Can't call 'unwatch' when 'subscribed'")
 
         return self.execute_command('UNWATCH')
 
diff --git a/redis/exceptions.py b/redis/exceptions.py
index 193016e..ffa574b 100644
--- a/redis/exceptions.py
+++ b/redis/exceptions.py
@@ -18,5 +18,9 @@ class InvalidResponse(RedisError):
 class DataError(RedisError):
     pass
 
+class PubSubError(RedisError):
+    pass
+
 class WatchError(RedisError):
     pass
+
diff --git a/tests/server_commands.py b/tests/server_commands.py
index fb5f3f5..742f356 100644
--- a/tests/server_commands.py
+++ b/tests/server_commands.py
@@ -1216,6 +1216,7 @@ class ServerCommandsTestCase(unittest.TestCase):
                 time.sleep(0.01)
 
         messages = []
+        self.assertRaises(redis.PubSubError, r.set, 'foo', 'bar')
         # should receive a message for each subscribe/unsubscribe command
         # plus a message for each iteration of the loop * num channels
         # we hide the data messages that tell the client to unsubscribe