Add CASE When Clause for saving order when using where IN

app/models/group.rb

@@ -251,7 +251,15 @@ class Group < Namespace
 
   def secret_variables_for(ref, project)
     list_of_ids = ([self] + ancestors).map { |l| l.id }
-    variables = Ci::GroupVariable.where("group_id IN (#{list_of_ids.join(", ")})")
+
+    order = list_of_ids.map.with_index do |id, index|
+      "WHEN #{id} THEN #{index}"
+    end.join("\n")
+
+    variables = Ci::GroupVariable
+      .where("group_id IN (#{list_of_ids.join(", ")})")
+      .order("CASE group_id #{order} END DESC")
+
     project.protected_for?(ref) ? variables : variables.unprotected
   end
 

spec/models/group_spec.rb

@@ -466,14 +466,21 @@ describe Group, models: true do
       it_behaves_like 'ref is protected'
     end
 
-    context 'when group has a child' do
-      let!(:group_child) { create(:group, :access_requestable, parent: group) }
+    context 'when group has children' do
+      let!(:group_child) { create(:group, parent: group) }
       let!(:variable_child) { create(:ci_group_variable, group: group_child) }
-
-      subject { group_child.secret_variables_for('ref', project) }
+      let!(:group_child_3) { create(:group, parent: group_child_2) }
+      let!(:variable_child_3) { create(:ci_group_variable, group: group_child_3) }
+      let!(:group_child_2) { create(:group, parent: group_child) }
+      let!(:variable_child_2) { create(:ci_group_variable, group: group_child_2) }
 
       it 'returns all variables belong to the group and parent groups' do
-        is_expected.to contain_exactly(secret_variable, protected_variable, variable_child)
+        expected_array1 = [protected_variable, secret_variable]
+        expected_array2 = [variable_child, variable_child_2, variable_child_3]
+        got_array = group_child_3.secret_variables_for('ref', project).to_a
+
+        expect(got_array.shift(2)).to contain_exactly(*expected_array1)
+        expect(got_array).to eq(expected_array2)
       end
     end
   end