Make add_host clear the inventory pattern cache, add some more aliases.

Fixes ansible#4442.

lib/ansible/inventory/__init__.py

@@ -266,6 +266,10 @@ def _hosts_in_unenumerated_pattern(self, pattern):
             self._pattern_hosts[pattern] = results
         return self._pattern_hosts[pattern]
 
+    def clear_pattern_cache(self):
+        ''' called exclusively by the add_host plugin to allow patterns to be recalculated '''
+        self._pattern_hosts = {}
+
     def groups_for_host(self, host):
         results = []
         groups = self.get_groups()

lib/ansible/runner/action_plugins/add_host.py

@@ -68,14 +68,14 @@ def run(self, conn, tmp, module_name, module_args, inject, complex_args=None, **
             # only groups can be added directly to inventory
             inventory._hosts_cache[new_name] = new_host
             allgroup.add_host(new_host)
- 
+
         # Add any variables to the new_host
         for k in args.keys():
             if not k in [ 'name', 'hostname', 'groupname', 'groups' ]:
                 new_host.set_variable(k, args[k]) 
 
 
-        groupnames = args.get('groupname', args.get('groups', '')) 
+        groupnames = args.get('groupname', args.get('groups', args.get('group', ''))) 
         # add it to the group if that was specified
         if groupnames != '':
             for group_name in groupnames.split(","):
@@ -88,6 +88,10 @@ def run(self, conn, tmp, module_name, module_args, inject, complex_args=None, **
             result['new_groups'] = groupnames.split(",")
 
         result['new_host'] = new_name
+
+        # clear pattern caching completely since it's unpredictable what
+        # patterns may have referenced the group
+        inventory.clear_pattern_cache()
 
         return ReturnData(conn=conn, comm_ok=True, result=result)
 

library/inventory/add_host

@@ -10,12 +10,12 @@ description:
 version_added: "0.9"
 options:
   name:
-    aliases: [ 'hostname' ]
+    aliases: [ 'hostname', 'host' ]
     description:
     - The hostname/ip of the host to add to the inventory, can include a colon and a port number.
     required: true     
   groups:
-    aliases: [ 'groupname' ]
+    aliases: [ 'groupname', 'group' ]
     description:
     - The groups to add the hostname to, comma separated.
     required: false