Merge pull request #42469 from rallytime/bp-42027

Back-port #42027 to 2017.7.1

salt/utils/event.py

@@ -59,6 +59,7 @@ import fnmatch
 import hashlib
 import logging
 import datetime
+import sys
 from collections import MutableMapping
 from multiprocessing.util import Finalize
 from salt.ext.six.moves import range
@@ -1159,6 +1160,16 @@ class EventReturn(salt.utils.process.SignalHandlingMultiprocessingProcess):
     A dedicated process which listens to the master event bus and queues
     and forwards events to the specified returner.
     '''
+    def __new__(cls, *args, **kwargs):
+        if sys.platform.startswith('win'):
+            # This is required for Windows.  On Linux, when a process is
+            # forked, the module namespace is copied and the current process
+            # gets all of sys.modules from where the fork happens.  This is not
+            # the case for Windows.
+            import salt.minion
+        instance = super(EventReturn, cls).__new__(cls, *args, **kwargs)
+        return instance
+
     def __init__(self, opts, log_queue=None):
         '''
         Initialize the EventReturn system