Fix for #3062 additional groups should only be added once.

Also consolidated duplicate groups code into one get_groups_set() method.
Removed unused call to user_group_membership.
Removed sorting operations on set functions cause sets are inherently unordered.
Minor style improvements to match the rest of the code.

The new function will make the order of group names passed to the system command less determistic.
Which was already the case for modify_user_usermod() but not for other methods.
It will also strip out duplicate group names automatically which was not always the case previously.

library/system/user

@@ -179,8 +179,8 @@ except:
 class User(object):
     """
     This is a generic User manipulation class that is subclassed
-    based on platform.  
-    
+    based on platform.
+
     A subclass may wish to override the following action methods:-
       - create_user()
       - remove_user()
@@ -229,7 +229,7 @@ class User(object):
         # select whether we dump additional debug info through syslog
         self.syslogging = False
 
-    def execute_command(self,cmd):
+    def execute_command(self, cmd):
         if self.syslogging:
             syslog.openlog('ansible-%s' % os.path.basename(__file__))
             syslog.syslog(syslog.LOG_NOTICE, 'Command %s' % '|'.join(cmd))
@@ -263,12 +263,9 @@ class User(object):
             cmd.append(self.group)
 
         if self.groups is not None:
-            if self.groups != '':
-                for g in self.groups.split(','):
-                    if not self.group_exists(g):
-                        self.module.fail_json(msg="Group %s does not exist" % (g))
+            groups = self.get_groups_set()
             cmd.append('-G')
-            cmd.append(self.groups)
+            cmd.append(','.join(groups))
 
         if self.comment is not None:
             cmd.append('-c')
@@ -326,12 +323,8 @@ class User(object):
                 if current_groups and not self.append:
                     groups_need_mod = True
             else:
-                groups = self.groups.split(',')
-                for g in groups:
-                    if not self.group_exists(g):
-                        self.module.fail_json(msg="Group %s does not exist" % (g))
-
-                group_diff = set(sorted(current_groups)).symmetric_difference(set(sorted(groups)))
+                groups = self.get_groups_set()
+                group_diff = set(current_groups).symmetric_difference(groups)
 
                 if group_diff:
                     if self.append:
@@ -370,6 +363,7 @@ class User(object):
             return (0, '', '')
 
         cmd.append(self.name)
+        open("/tmp/xxx.log", "a").write(str(cmd)+"\n")
         return self.execute_command(cmd)
 
     def group_exists(self,group):
@@ -391,11 +385,23 @@ class User(object):
         else:
             return list(grp.getgrnam(group))
 
+    def get_groups_set(self):
+        if self.groups is None:
+            return None
+        info = self.user_info()
+        groups = set(self.groups.split(','))
+        for g in set(groups):
+            if not self.group_exists(g):
+                self.module.fail_json(msg="Group %s does not exist" % (g))
+            if info and self.group_info(g)[2] == info[3]:
+                groups.remove(g)
+        return groups
+
     def user_group_membership(self):
         groups = []
         info = self.get_pwd_info()
         for group in grp.getgrall():
-            if self.name in group.gr_mem and info[3] == group.gr_gid:
+            if self.name in group.gr_mem and not info[3] == group.gr_gid:
                 groups.append(group[0])
         return groups
 
@@ -574,11 +580,9 @@ class FreeBsdUser(User):
             cmd.append(self.group)
 
         if self.groups is not None:
-            for g in self.groups.split(','):
-                if not self.group_exists(g):
-                    self.module.fail_json(msg="Group %s does not exist" % (g))
+            groups = self.get_groups_set()
             cmd.append('-G')
-            cmd.append(self.groups)
+            cmd.append(','.join(groups))
 
         if self.createhome:
             cmd.append('-m')
@@ -641,15 +645,12 @@ class FreeBsdUser(User):
         if self.shell is not None and info[6] != self.shell:
             cmd.append('-s')
             cmd.append(self.shell)
-        
+
         if self.groups is not None:
             current_groups = self.user_group_membership()
-            groups = self.groups.split(',')
-            for g in groups:
-                if not self.group_exists(g):
-                    self.module.fail_json(msg="Group %s does not exist" % (g))
+            groups = self.get_groups_set()
 
-            group_diff = set(sorted(current_groups)).symmetric_difference(set(sorted(groups)))
+            group_diff = set(current_groups).symmetric_difference(groups)
             groups_need_mod = False
 
             if group_diff:
@@ -665,7 +666,7 @@ class FreeBsdUser(User):
                 cmd.append('-G')
                 new_groups = groups
                 if self.append:
-                    new_groups.extend(current_groups)           
+                    new_groups.extend(current_groups)
                 cmd.append(','.join(new_groups))
 
         # modify the user if cmd will do anything
@@ -696,7 +697,7 @@ class SunOS(User):
     this class and the generic user class is that Solaris-type distros
     don't support the concept of a "system" account and we need to 
     edit the /etc/shadow file manually to set a password. (Ugh)
-    
+
     This overrides the following methods from the generic class:-
       - create_user()
       - remove_user()
@@ -732,11 +733,9 @@ class SunOS(User):
             cmd.append(self.group)
 
         if self.groups is not None:
-            for g in self.groups.split(','):
-                if not self.group_exists(g):
-                    self.module.fail_json(msg="Group %s does not exist" % (g))
+            groups = self.get_groups_set()
             cmd.append('-G')
-            cmd.append(self.groups)
+            cmd.append(','.join(groups))
 
         if self.comment is not None:
             cmd.append('-c')
@@ -771,7 +770,7 @@ class SunOS(User):
                     fields[1] = self.password
                     line = ':'.join(fields)
                     lines.append('%s\n' % line)
-                open(self.SHADOWFILE, 'w+').writelines(lines)        
+                open(self.SHADOWFILE, 'w+').writelines(lines)
             except Exception, err:
                 self.module.fail_json(msg="failed to update users password: %s" % str(err))
 
@@ -799,12 +798,8 @@ class SunOS(User):
 
         if self.groups is not None:
             current_groups = self.user_group_membership()
-            groups = self.groups.split(',')
-            for g in groups:
-                if not self.group_exists(g):
-                    self.module.fail_json(msg="Group %s does not exist" % (g))
-
-            group_diff = set(sorted(current_groups)).symmetric_difference(set(sorted(groups)))
+            groups = self.get_groups_set()
+            group_diff = set(current_groups).symmetric_difference(groups)
             groups_need_mod = False
 
             if group_diff:
@@ -820,7 +815,7 @@ class SunOS(User):
                 cmd.append('-G')
                 new_groups = groups
                 if self.append:
-                    new_groups.extend(current_groups)           
+                    new_groups.extend(current_groups)
                 cmd.append(','.join(new_groups))
 
         if self.comment is not None and info[4] != self.comment:
@@ -856,7 +851,7 @@ class SunOS(User):
                     fields[1] = self.password
                     line = ':'.join(fields)
                     lines.append('%s\n' % line)
-                open(self.SHADOWFILE, 'w+').writelines(lines)        
+                open(self.SHADOWFILE, 'w+').writelines(lines)
                 rc = 0
             except Exception, err:
                 self.module.fail_json(msg="failed to update users password: %s" % str(err))
@@ -901,11 +896,9 @@ class AIX(User):
             cmd.append(self.group)
 
         if self.groups is not None:
-            for g in self.groups.split(','):
-                if not self.group_exists(g):
-                    self.module.fail_json(msg="Group %s does not exist" % (g))
+            groups = self.get_groups_set()
             cmd.append('-G')
-            cmd.append(self.groups)
+            cmd.append(','.join(groups))
 
         if self.comment is not None:
             cmd.append('-c')
@@ -954,12 +947,8 @@ class AIX(User):
 
         if self.groups is not None:
             current_groups = self.user_group_membership()
-            groups = self.groups.split(',')
-            for g in groups:
-                if not self.group_exists(g):
-                    self.module.fail_json(msg="Group %s does not exist" % (g))
-
-            group_diff = set(sorted(current_groups)).symmetric_difference(set(sorted(groups)))
+            groups = self.get_groups_set()
+            group_diff = set(current_groups).symmetric_difference(groups)
             groups_need_mod = False
 
             if group_diff:
@@ -1113,7 +1102,6 @@ def main():
         result['comment'] = info[4]
         result['home'] = info[5]
         result['shell'] = info[6]
-        groups = user.user_group_membership()
         result['uid'] = info[2]
         if user.groups is not None:
             result['groups'] = user.groups