Update :with_shared_runners_limit_enabled scope

Do not include public project into :with_shared_runners_limit_enabled
scope if `public_projects_minutes_cost_factor` of shared runners set to
0.

ee/app/models/ee/ci/runner.rb

@@ -27,6 +27,14 @@ module EE
           minutes_cost_factor(visibility_level).positive?
         end
       end
+
+      class << self
+        def has_shared_runners_with_non_zero_public_cost?
+          Rails.cache.fetch(:shared_runners_public_cost_factor, expires_in: 1.day) do
+            ::Ci::Runner.instance_type.where('public_projects_minutes_cost_factor > 0').exists?
+          end
+        end
+      end
     end
   end
 end

ee/app/models/ee/project.rb

@@ -93,7 +93,8 @@ module EE
       has_many :sourced_pipelines, class_name: 'Ci::Sources::Project', foreign_key: :source_project_id
 
       scope :with_shared_runners_limit_enabled, -> do
-        if ::Feature.enabled?(:ci_minutes_enforce_quota_for_public_projects)
+        if ::Feature.enabled?(:ci_minutes_enforce_quota_for_public_projects) &&
+            ::EE::Ci::Runner.has_shared_runners_with_non_zero_public_cost?
           with_shared_runners
         else
           with_shared_runners.non_public_only

ee/spec/models/project_spec.rb

@@ -187,6 +187,12 @@ describe Project do
     end
 
     describe '.with_shared_runners_limit_enabled' do
+      let(:public_cost_factor) { 1.0 }
+
+      before do
+        create(:ci_runner, :instance, public_projects_minutes_cost_factor: public_cost_factor)
+      end
+
       it 'does not return projects without shared runners' do
         project_with_shared_runners = create(:project, shared_runners_enabled: true)
         project_without_shared_runners = create(:project, shared_runners_enabled: false)
@@ -195,7 +201,7 @@ describe Project do
         expect(described_class.with_shared_runners_limit_enabled).not_to include(project_without_shared_runners)
       end
 
-      it 'return projects with shared runners with any visibility levels' do
+      it 'return projects with shared runners with positive public cost factor with any visibility levels' do
         public_project_with_shared_runners = create(:project, :public, shared_runners_enabled: true)
         internal_project_with_shared_runners = create(:project, :internal, shared_runners_enabled: true)
         private_project_with_shared_runners = create(:project, :private, shared_runners_enabled: true)
@@ -205,6 +211,20 @@ describe Project do
         expect(described_class.with_shared_runners_limit_enabled).to include(private_project_with_shared_runners)
       end
 
+      context 'and shared runners public cost factors set to 0' do
+        let(:public_cost_factor) { 0.0 }
+
+        it 'return projects with any visibility levels except public' do
+          public_project_with_shared_runners = create(:project, :public, shared_runners_enabled: true)
+          internal_project_with_shared_runners = create(:project, :internal, shared_runners_enabled: true)
+          private_project_with_shared_runners = create(:project, :private, shared_runners_enabled: true)
+
+          expect(described_class.with_shared_runners_limit_enabled).not_to include(public_project_with_shared_runners)
+          expect(described_class.with_shared_runners_limit_enabled).to include(internal_project_with_shared_runners)
+          expect(described_class.with_shared_runners_limit_enabled).to include(private_project_with_shared_runners)
+        end
+      end
+
       context 'and :ci_minutes_enforce_quota_for_public_projects FF is disabled' do
         before do
           stub_feature_flags(ci_minutes_enforce_quota_for_public_projects: false)