Replace Ci::Runner with linear scopes

In this commit we're replacing the recursive ancestors scope in
the `Ci::Runner` model, for their linear version.

Changelog: performance

app/models/ci/runner.rb

@@ -84,7 +84,11 @@ module Ci
       groups = ::Group.where(id: group_id)
 
       if include_ancestors
-        groups = Gitlab::ObjectHierarchy.new(groups).base_and_ancestors
+        groups = if Feature.enabled?(:linear_runner_ancestor_scopes, default_enabled: :yaml)
+                   groups.self_and_ancestors
+                 else
+                   Gitlab::ObjectHierarchy.new(groups).base_and_ancestors
+                 end
       end
 
       joins(:runner_namespaces)
@@ -106,7 +110,11 @@ module Ci
 
     scope :belonging_to_parent_group_of_project, -> (project_id) {
       project_groups = ::Group.joins(:projects).where(projects: { id: project_id })
-      hierarchy_groups = Gitlab::ObjectHierarchy.new(project_groups).base_and_ancestors
+      hierarchy_groups = if Feature.enabled?(:linear_runner_ancestor_scopes, default_enabled: :yaml)
+                           project_groups.self_and_ancestors.as_ids
+                         else
+                           Gitlab::ObjectHierarchy.new(project_groups).base_and_ancestors
+                         end
 
       joins(:groups)
         .where(namespaces: { id: hierarchy_groups })

config/feature_flags/development/linear_runner_ancestor_scopes.yml

+---
+name: linear_runner_ancestor_scopes
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/70385
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/341114
+milestone: '14.6'
+type: development
+group: group::access
+default_enabled: false

spec/models/ci/runner_spec.rb

@@ -208,26 +208,38 @@ RSpec.describe Ci::Runner do
   end
 
   describe '.belonging_to_parent_group_of_project' do
-    let(:project) { create(:project, group: group) }
-    let(:group) { create(:group) }
-    let(:runner) { create(:ci_runner, :group, groups: [group]) }
-    let!(:unrelated_group) { create(:group) }
-    let!(:unrelated_project) { create(:project, group: unrelated_group) }
-    let!(:unrelated_runner) { create(:ci_runner, :group, groups: [unrelated_group]) }
+    shared_examples 'returns parent group project runners' do
+      let(:project) { create(:project, group: group) }
+      let(:group) { create(:group) }
+      let(:runner) { create(:ci_runner, :group, groups: [group]) }
+      let!(:unrelated_group) { create(:group) }
+      let!(:unrelated_project) { create(:project, group: unrelated_group) }
+      let!(:unrelated_runner) { create(:ci_runner, :group, groups: [unrelated_group]) }
+
+      it 'returns the specific group runner' do
+        expect(described_class.belonging_to_parent_group_of_project(project.id)).to contain_exactly(runner)
+      end
 
-    it 'returns the specific group runner' do
-      expect(described_class.belonging_to_parent_group_of_project(project.id)).to contain_exactly(runner)
+      context 'with a parent group with a runner' do
+        let(:runner) { create(:ci_runner, :group, groups: [parent_group]) }
+        let(:project) { create(:project, group: group) }
+        let(:group) { create(:group, parent: parent_group) }
+        let(:parent_group) { create(:group) }
+
+        it 'returns the group runner from the parent group' do
+          expect(described_class.belonging_to_parent_group_of_project(project.id)).to contain_exactly(runner)
+        end
+      end
     end
 
-    context 'with a parent group with a runner' do
-      let(:runner) { create(:ci_runner, :group, groups: [parent_group]) }
-      let(:project) { create(:project, group: group) }
-      let(:group) { create(:group, parent: parent_group) }
-      let(:parent_group) { create(:group) }
+    it_behaves_like 'returns parent group project runners'
 
-      it 'returns the group runner from the parent group' do
-        expect(described_class.belonging_to_parent_group_of_project(project.id)).to contain_exactly(runner)
+    context 'when feature flag :linear_runner_ancestor_scopes is disabled' do
+      before do
+        stub_feature_flags(linear_runner_ancestor_scopes: false)
       end
+
+      it_behaves_like 'returns parent group project runners'
     end
   end
 
@@ -1259,31 +1271,43 @@ RSpec.describe Ci::Runner do
   end
 
   describe '.belonging_to_group' do
-    it 'returns the specific group runner' do
-      group = create(:group)
-      runner = create(:ci_runner, :group, groups: [group])
-      unrelated_group = create(:group)
-      create(:ci_runner, :group, groups: [unrelated_group])
+    shared_examples 'returns group runners' do
+      it 'returns the specific group runner' do
+        group = create(:group)
+        runner = create(:ci_runner, :group, groups: [group])
+        unrelated_group = create(:group)
+        create(:ci_runner, :group, groups: [unrelated_group])
 
-      expect(described_class.belonging_to_group(group.id)).to contain_exactly(runner)
-    end
+        expect(described_class.belonging_to_group(group.id)).to contain_exactly(runner)
+      end
 
-    context 'runner belonging to parent group' do
-      let_it_be(:parent_group) { create(:group) }
-      let_it_be(:parent_runner) { create(:ci_runner, :group, groups: [parent_group]) }
-      let_it_be(:group) { create(:group, parent: parent_group) }
+      context 'runner belonging to parent group' do
+        let_it_be(:parent_group) { create(:group) }
+        let_it_be(:parent_runner) { create(:ci_runner, :group, groups: [parent_group]) }
+        let_it_be(:group) { create(:group, parent: parent_group) }
 
-      context 'when include_parent option is passed' do
-        it 'returns the group runner from the parent group' do
-          expect(described_class.belonging_to_group(group.id, include_ancestors: true)).to contain_exactly(parent_runner)
+        context 'when include_parent option is passed' do
+          it 'returns the group runner from the parent group' do
+            expect(described_class.belonging_to_group(group.id, include_ancestors: true)).to contain_exactly(parent_runner)
+          end
         end
-      end
 
-      context 'when include_parent option is not passed' do
-        it 'does not return the group runner from the parent group' do
-          expect(described_class.belonging_to_group(group.id)).to be_empty
+        context 'when include_parent option is not passed' do
+          it 'does not return the group runner from the parent group' do
+            expect(described_class.belonging_to_group(group.id)).to be_empty
+          end
         end
       end
     end
+
+    it_behaves_like 'returns group runners'
+
+    context 'when feature flag :linear_runner_ancestor_scopes is disabled' do
+      before do
+        stub_feature_flags(linear_runner_ancestor_scopes: false)
+      end
+
+      it_behaves_like 'returns group runners'
+    end
   end
 end