Allow to include also descendant group labelsjprovazn-ancestor-labels

Because epic index page includes also epics from subgroups
it's necessary to also get descendant group labels for filtering.
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4773#note_61236542

3 files changed, 32 insertions, 4 deletions

diff --git a/app/controllers/groups/labels_controller.rb b/app/controllers/groups/labels_controller.rb
index 2e4cec830bb..ac1d97dc54a 100644
--- a/app/controllers/groups/labels_controller.rb
+++ b/app/controllers/groups/labels_controller.rb
@@ -18,7 +18,8 @@ class Groups::LabelsController < Groups::ApplicationController
           current_user,
           group_id: @group.id,
           only_group_labels: params[:only_group_labels],
-          include_ancestor_groups: params[:include_ancestor_groups]
+          include_ancestor_groups: params[:include_ancestor_groups],
+          include_descendant_groups: params[:include_descendant_groups]
         ).execute
 
         render json: LabelSerializer.new.represent_appearance(available_labels)
diff --git a/app/finders/labels_finder.rb b/app/finders/labels_finder.rb
index 5c9fce211ec..780c0fdb03e 100644
--- a/app/finders/labels_finder.rb
+++ b/app/finders/labels_finder.rb
@@ -61,12 +61,20 @@ class LabelsFinder < UnionFinder
 
   def group_ids
     strong_memoize(:group_ids) do
-      group = Group.find(params[:group_id])
-      groups = params[:include_ancestor_groups].present? ? group.self_and_ancestors : [group]
-      groups_user_can_read_labels(groups).map(&:id)
+      groups_user_can_read_labels(groups_to_include).map(&:id)
     end
   end
 
+  def groups_to_include
+    group = Group.find(params[:group_id])
+    groups = [group]
+
+    groups += group.ancestors if params[:include_ancestor_groups].present?
+    groups += group.descendants if params[:include_descendant_groups].present?
+
+    groups
+  end
+
   def group?
     params[:group_id].present?
   end
diff --git a/spec/finders/labels_finder_spec.rb b/spec/finders/labels_finder_spec.rb
index dc76efea35b..d434c501110 100644
--- a/spec/finders/labels_finder_spec.rb
+++ b/spec/finders/labels_finder_spec.rb
@@ -89,6 +89,25 @@ describe LabelsFinder do
           expect(finder.execute).to eq [private_subgroup_label_1]
         end
       end
+
+      context 'when including labels from group descendants', :nested_groups do
+        it 'returns labels from group and its descendants' do
+          private_group_1.add_developer(user)
+          private_subgroup_1.add_developer(user)
+
+          finder = described_class.new(user, group_id: private_group_1.id, only_group_labels: true, include_descendant_groups: true)
+
+          expect(finder.execute).to eq [private_group_label_1, private_subgroup_label_1]
+        end
+
+        it 'ignores labels from groups which user can not read' do
+          private_subgroup_1.add_developer(user)
+
+          finder = described_class.new(user, group_id: private_group_1.id, only_group_labels: true, include_descendant_groups: true)
+
+          expect(finder.execute).to eq [private_subgroup_label_1]
+        end
+      end
     end
 
     context 'filtering by project_id' do