Merge branch 'handle-smtp-input-errors' into 'master'

Gracefully handle SMTP user input errors (e.g. incorrect email addresses) to prevent Sidekiq retries

### What does this MR do?

This MR gracefully handles SMTP input errors (e.g. incorrect or invalid e-mail addresses) to prevent these types of exceptions from causing Sidekiq to retry the task. If these specific exceptions occur, they will be logged, and the e-mail will be dropped from the queue.

### Why was this MR needed?

If you include an author that has a misspelled e-mail address, Sidekiq will keep sending e-mail to all the recipients even if they have already received the e-mail. The only way to recover is to clear the Sidekiq queue.

Note that other exceptions can still be thrown (e.g. `IOError`, `Net::SMTPAuthenticationError`, `Net::SMTPServerBusy`, `Net::SMTPUnknownError`, and `TimeoutError`). If the worker encounters these, Sidekiq should retry the task.

### What are the relevant issue numbers?

Closes https://github.com/gitlabhq/gitlabhq/issues/9560

See merge request !1163

1 files changed, 34 insertions, 0 deletions

diff --git a/spec/workers/emails_on_push_worker_spec.rb b/spec/workers/emails_on_push_worker_spec.rb
new file mode 100644
index 00000000000..3600c771075
--- /dev/null
+++ b/spec/workers/emails_on_push_worker_spec.rb
@@ -0,0 +1,34 @@
+require 'spec_helper'
+
+describe EmailsOnPushWorker do
+  include RepoHelpers
+
+  let(:project) { create(:project) }
+  let(:user) { create(:user) }
+  let(:data) { Gitlab::PushDataBuilder.build_sample(project, user) }
+
+  subject { EmailsOnPushWorker.new }
+
+  before do
+    allow(Project).to receive(:find).and_return(project)
+  end
+
+  describe "#perform" do
+    it "sends mail" do
+      subject.perform(project.id, user.email, data.stringify_keys)
+
+      email = ActionMailer::Base.deliveries.last
+      expect(email.subject).to include('Change some files')
+      expect(email.to).to eq([user.email])
+    end
+
+    it "gracefully handles an input SMTP error" do
+      ActionMailer::Base.deliveries.clear
+      allow(Notify).to receive(:repository_push_email).and_raise(Net::SMTPFatalError)
+
+      subject.perform(project.id, user.email, data.stringify_keys)
+
+      expect(ActionMailer::Base.deliveries.count).to eq(0)
+    end
+  end
+end