Pull from head and a couple more tweaks.

4 files changed, 13 insertions, 9 deletions

diff --git a/cloudinit/mergers/__init__.py b/cloudinit/mergers/__init__.py
index e1ff57ba..f504e15f 100644
--- a/cloudinit/mergers/__init__.py
+++ b/cloudinit/mergers/__init__.py
@@ -26,6 +26,8 @@ NAME_MTCH = re.compile(r"(^[a-zA-Z_][A-Za-z0-9_]*)\((.*?)\)$")
 
 LOG = logging.getLogger(__name__)
 DEF_MERGE_TYPE = "list()+dict()+str()"
+MERGER_PREFIX = 'm_'
+MERGER_ATTR = 'Merger'
 
 
 class UnknownMerger(object):
@@ -136,15 +138,18 @@ def default_mergers():
 def construct(parsed_mergers):
     mergers_to_be = []
     for (m_name, m_ops) in parsed_mergers:
+        if not m_name.startswith(MERGER_PREFIX):
+            m_name = MERGER_PREFIX + str(m_name)
         merger_locs = importer.find_module(m_name,
                                            [__name__],
-                                           ['Merger'])
+                                           [MERGER_ATTR])
         if not merger_locs:
-            msg = "Could not find merger named '%s'" % (m_name)
+            msg = ("Could not find merger module named '%s' "
+                   "with attribute '%s'") % (m_name, MERGER_ATTR)
             raise ImportError(msg)
         else:
             mod = importer.import_module(merger_locs[0])
-            mod_attr = getattr(mod, 'Merger')
+            mod_attr = getattr(mod, MERGER_ATTR)
             mergers_to_be.append((mod_attr, m_ops))
     # Now form them...
     mergers = []
diff --git a/cloudinit/mergers/dict.py b/cloudinit/mergers/m_dict.py
index 929d3865..929d3865 100644
--- a/cloudinit/mergers/dict.py
+++ b/cloudinit/mergers/m_dict.py
diff --git a/cloudinit/mergers/list.py b/cloudinit/mergers/m_list.py
index 7c8b2e2a..208c5f52 100644
--- a/cloudinit/mergers/list.py
+++ b/cloudinit/mergers/m_list.py
@@ -28,11 +28,10 @@ class Merger(object):
     # On encountering a list or tuple type this action will be applied
     # a new list will be returned, if the value to merge with is itself
     # a list and we have been told to 'extend', then the value here will
-    # be extended with the other list. If in 'extend' mode then we will
-    # attempt to merge instead, which means that values from the list
-    # to merge with will replace values in te original list (they will
-    # also be merged recursively).
+    # be extended with the other list.
     def _on_list(self, value, merge_with):
         if not self._extend or not isinstance(merge_with, (tuple, list)):
             return merge_with
-        return list(value).extend(merge_with)
+        # Leave the original list alone...
+        value = list(value)
+        return value.extend(merge_with)
diff --git a/cloudinit/mergers/str.py b/cloudinit/mergers/m_str.py
index 291c91c2..a0c57b53 100644
--- a/cloudinit/mergers/str.py
+++ b/cloudinit/mergers/m_str.py
@@ -31,7 +31,7 @@ class Merger(object):
     # merge them together, otherwise we will just return value.
     def _on_str(self, value, merge_with):
         if not self._append:
-            return value
+            return merge_with
         else:
             if isinstance(value, (unicode)):
                 return value + unicode(merge_with)