Make sure it checks against the tag only when it's a tag

Author: godfat

app/policies/ci/build_policy.rb

@@ -5,8 +5,11 @@ class BuildPolicy < CommitStatusPolicy
 
       access = ::Gitlab::UserAccess.new(@user, project: @subject.project)
 
-      !access.can_merge_to_branch?(@subject.ref) ||
+      if @subject.tag?
         !access.can_create_tag?(@subject.ref)
+      else
+        !access.can_merge_to_branch?(@subject.ref)
+      end
     end
 
     rule { protected_action }.prevent :update_build

spec/policies/ci/build_policy_spec.rb

@@ -138,11 +138,30 @@
         before do
           create(:protected_tag, :no_one_can_create,
                  name: 'some-ref', project: project)
+
+          build.update(tag: true)
         end
 
         it_behaves_like 'protected ref'
       end
 
+      context 'when build is against a protected tag but it is not a tag' do
+        before do
+          create(:protected_tag, :no_one_can_create,
+                 name: 'some-ref', project: project)
+        end
+
+        context 'when build is a manual action' do
+          let(:build) do
+            create(:ci_build, :manual, ref: 'some-ref', pipeline: pipeline)
+          end
+
+          it 'includes ability to update build' do
+            expect(policy).to be_allowed :update_build
+          end
+        end
+      end
+
       context 'when branch build is assigned to is not protected' do
         context 'when build is a manual action' do
           let(:build) { create(:ci_build, :manual, pipeline: pipeline) }