Fix a bug doubling module name prefix

Author: ericzbeard

awscli/customizations/cloudformation/module_maps.py

@@ -161,7 +161,12 @@ def vf(v):
 
 
 def getatt_map_list(getatt):
-    "Converts a getatt array like ['Content[]', 'Arn'] to a string"
+    """
+    Converts a getatt array like ['Content[]', 'Arn'] to a string,
+    joining with a dot. 'Content[].Arn'
+    Returns None if the getatt is not a list at least 2 elements long,
+    and if the first element does not contain '[]'
+    """
     if isinstance(getatt, list) and len(getatt) > 1:
         if "[]" in getatt[0]:
             return ".".join(getatt)  # Content[].Arn

awscli/customizations/cloudformation/modules.py

@@ -26,6 +26,7 @@
 
 # pylint: disable=fixme,too-many-instance-attributes,too-many-lines
 
+import copy
 import logging
 import os
 
@@ -587,8 +588,8 @@ def resolve_output_getatt(self, v, d, n):
             if s is not None and s in self.mapped:
                 # Special handling for Overrides that GetAtt a module
                 # property, when that module has a Map attribute
-                d[n] = self.mapped[s]
-                if isinstance(d[n], list):
+                if isinstance(self.mapped[s], list):
+                    d[n] = copy.deepcopy(self.mapped[s])
                     for item in d[n]:
                         if GETATT in item and len(item[GETATT]) > 0:
                             item[GETATT][0] = self.name + item[GETATT][0]