#4383: UnboundLocalError when IDLE cannot connect to its subprocess.

Python 3.0 clears the exception variable upon exit of the "except:" clause,
and the displaying code fails miserably.

Reviewed by Benjamin.

Lib/idlelib/run.py

@@ -119,10 +119,11 @@ def manage_socket(address):
         except socket.error as err:
             print("IDLE Subprocess: socket error: " + err.args[1] +
                   ", retrying....", file=sys.__stderr__)
+            socket_error = err
     else:
-        print("IDLE Subprocess: Connection to "\
-                               "IDLE GUI failed, exiting.", file=sys.__stderr__)
-        show_socket_error(err, address)
+        print("IDLE Subprocess: Connection to "
+              "IDLE GUI failed, exiting.", file=sys.__stderr__)
+        show_socket_error(socket_error, address)
         global exit_now
         exit_now = True
         return

Misc/NEWS

@@ -15,6 +15,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #4383: When IDLE cannot make the connection to its subprocess, it would
+  fail to properly display the error message.
+
 
 What's New in Python 3.0 release candidate 3?
 =============================================