Send only to users have :read_build access, feedback:

app/policies/ci/build_policy.rb

@@ -5,7 +5,7 @@ module Ci
 
       # If we can't read build we should also not have that
       # ability when looking at this in context of commit_status
-      %w(read create update admin).each do |rule|
+      %w[read create update admin].each do |rule|
         cannot! :"#{rule}_commit_status" unless can? :"#{rule}_build"
       end
     end

app/policies/ci/pipeline_policy.rb

+module Ci
+  class PipelinePolicy < BuildPolicy
+  end
+end

app/services/notification_service.rb

@@ -489,9 +489,14 @@ class NotificationService
   end
 
   def reject_users_without_access(recipients, target)
-    return recipients unless target.is_a?(Issuable)
-
-    ability = :"read_#{target.to_ability_name}"
+    ability = case target
+              when Issuable
+                :"read_#{target.to_ability_name}"
+              when Ci::Pipeline
+                :read_build # We have build trace in pipeline emails
+              end
+
+    return recipients unless ability
 
     recipients.select do |user|
       user.can?(ability, target)

spec/workers/pipeline_notification_worker_spec.rb

@@ -17,84 +17,114 @@ describe PipelineNotificationWorker do
   describe '#execute' do
     before do
       reset_delivered_emails!
-      pipeline.project.team << [watcher, Gitlab::Access::DEVELOPER]
+      pipeline.project.team << [pusher, Gitlab::Access::DEVELOPER]
     end
 
-    shared_examples 'sending emails' do
-      it 'sends emails' do
-        perform_enqueued_jobs do
-          subject.perform(pipeline.id)
-        end
+    context 'when watcher has developer access' do
+      before do
+        pipeline.project.team << [watcher, Gitlab::Access::DEVELOPER]
+      end
 
-        emails = ActionMailer::Base.deliveries
-        actual = emails.flat_map(&:bcc).sort
-        expected_receivers = [pusher, watcher].map(&:email).uniq.sort
+      shared_examples 'sending emails' do
+        it 'sends emails' do
+          perform_enqueued_jobs do
+            subject.perform(pipeline.id)
+          end
 
-        expect(actual).to eq(expected_receivers)
-        expect(emails.size).to eq(1)
-        expect(emails.last.subject).to include(email_subject)
-      end
-    end
+          emails = ActionMailer::Base.deliveries
+          actual = emails.flat_map(&:bcc).sort
+          expected_receivers = receivers.map(&:email).uniq.sort
 
-    context 'with success pipeline' do
-      let(:status) { 'success' }
-      let(:email_subject) { "Pipeline ##{pipeline.id} has succeeded" }
+          expect(actual).to eq(expected_receivers)
+          expect(emails.size).to eq(1)
+          expect(emails.last.subject).to include(email_subject)
+        end
+      end
 
-      it_behaves_like 'sending emails'
+      context 'with success pipeline' do
+        let(:status) { 'success' }
+        let(:email_subject) { "Pipeline ##{pipeline.id} has succeeded" }
+        let(:receivers) { [pusher, watcher] }
 
-      context 'with pipeline from someone else' do
-        let(:pusher) { create(:user) }
+        it_behaves_like 'sending emails'
 
-        context 'with success pipeline notification on' do
+        context 'with pipeline from someone else' do
+          let(:pusher) { create(:user) }
           let(:watcher) { user }
 
-          before do
-            watcher.global_notification_setting.
-              update(level: 'custom', success_pipeline: true)
+          context 'with success pipeline notification on' do
+            before do
+              watcher.global_notification_setting.
+                update(level: 'custom', success_pipeline: true)
+            end
+
+            it_behaves_like 'sending emails'
           end
 
-          it_behaves_like 'sending emails'
-        end
+          context 'with success pipeline notification off' do
+            let(:receivers) { [pusher] }
+
+            before do
+              watcher.global_notification_setting.
+                update(level: 'custom', success_pipeline: false)
+            end
 
-        context 'with success pipeline notification off' do
-          before do
-            watcher.global_notification_setting.
-              update(level: 'custom', success_pipeline: false)
+            it_behaves_like 'sending emails'
           end
+        end
+
+        context 'with failed pipeline' do
+          let(:status) { 'failed' }
+          let(:email_subject) { "Pipeline ##{pipeline.id} has failed" }
 
           it_behaves_like 'sending emails'
+
+          context 'with pipeline from someone else' do
+            let(:pusher) { create(:user) }
+            let(:watcher) { user }
+
+            context 'with failed pipeline notification on' do
+              before do
+                watcher.global_notification_setting.
+                  update(level: 'custom', failed_pipeline: true)
+              end
+
+              it_behaves_like 'sending emails'
+            end
+
+            context 'with failed pipeline notification off' do
+              let(:receivers) { [pusher] }
+
+              before do
+                watcher.global_notification_setting.
+                  update(level: 'custom', failed_pipeline: false)
+              end
+
+              it_behaves_like 'sending emails'
+            end
+          end
         end
       end
     end
 
-    context 'with failed pipeline' do
+    context 'when watcher has no read_build access' do
       let(:status) { 'failed' }
       let(:email_subject) { "Pipeline ##{pipeline.id} has failed" }
+      let(:watcher) { create(:user) }
 
-      it_behaves_like 'sending emails'
+      before do
+        pipeline.project.team << [watcher, Gitlab::Access::GUEST]
 
-      context 'with pipeline from someone else' do
-        let(:pusher) { create(:user) }
-
-        context 'with failed pipeline notification on' do
-          let(:watcher) { user }
-
-          before do
-            watcher.global_notification_setting.
-              update(level: 'custom', failed_pipeline: true)
-          end
+        watcher.global_notification_setting.
+          update(level: 'custom', failed_pipeline: true)
 
-          it_behaves_like 'sending emails'
+        perform_enqueued_jobs do
+          subject.perform(pipeline.id)
         end
+      end
 
-        context 'with failed pipeline notification off' do
-          before do
-            watcher.global_notification_setting.
-              update(level: 'custom', failed_pipeline: false)
-          end
-
-          it_behaves_like 'sending emails'
-        end
+      it 'does not send emails' do
+        should_only_email(pusher, kind: :bcc)
       end
     end
   end