[#2845] Apply allow_partial_update to all group fields

Make 'allow_partial_update': True in the context apply to multiple group
fields: packages, users, groups, tags and extras, when updating a group,
so you can pass a group dict with e.g. no 'packages' key and this will
update the group but will not change the group's packages.  Previously
allow_partial_update only affected packages and extras.

ckan/lib/dictization/model_save.py

@@ -320,6 +320,10 @@ def group_member_save(context, group_dict, member_table_name):
     session = context["session"]
     group = context['group']
     entity_list = group_dict.get(member_table_name, [])
+
+    if entity_list == [] and context.get('allow_partial_update', False):
+        return {'added': [], 'removed': []}
+
     entities = {}
     Member = model.Member
 
@@ -382,22 +386,21 @@ def group_dict_save(group_dict, context):
 
     context['group'] = group
 
-    if group_dict.get('packages', None) or not allow_partial_update:
-        pkgs_edited = group_member_save(context, group_dict, 'packages')
-        group_users_changed = group_member_save(context, group_dict, 'users')
-        group_groups_changed = group_member_save(context, group_dict, 'groups')
-        group_tags_changed = group_member_save(context, group_dict, 'tags')
-        log.debug('Group save membership changes - Packages: %r  Users: %r  '
-                'Groups: %r  Tags: %r', pkgs_edited, group_users_changed,
-                group_groups_changed, group_tags_changed)
-
-        # We will get a list of packages that we have either added or
-        # removed from the group, and trigger a re-index.
-        package_ids = pkgs_edited['removed']
-        package_ids.extend( pkgs_edited['added'] )
-        if package_ids:
-            session.commit()
-            map( rebuild, package_ids )
+    pkgs_edited = group_member_save(context, group_dict, 'packages')
+    group_users_changed = group_member_save(context, group_dict, 'users')
+    group_groups_changed = group_member_save(context, group_dict, 'groups')
+    group_tags_changed = group_member_save(context, group_dict, 'tags')
+    log.debug('Group save membership changes - Packages: %r  Users: %r  '
+            'Groups: %r  Tags: %r', pkgs_edited, group_users_changed,
+            group_groups_changed, group_tags_changed)
+
+    # We will get a list of packages that we have either added or
+    # removed from the group, and trigger a re-index.
+    package_ids = pkgs_edited['removed']
+    package_ids.extend( pkgs_edited['added'] )
+    if package_ids:
+        session.commit()
+        map( rebuild, package_ids )
 
     extras = group_extras_save(group_dict.get("extras", {}), context)
     if extras or not allow_partial_update: