Merge branch...

Merge branch 'qmnguyen0711/364326-nomethoderror-undefined-method-find-for-nil-nilclass' into 'master'

Guard email receiver from empty From and To fields

See merge request gitlab-org/gitlab!89296

lib/gitlab/email/receiver.rb

@@ -32,8 +32,8 @@ def execute
       def mail_metadata
         {
           mail_uid: mail.message_id,
-          from_address: mail.from,
-          to_address: mail.to,
+          from_address: from,
+          to_address: to,
           mail_key: mail_key,
           references: Array(mail.references),
           delivered_to: delivered_to.map(&:value),
@@ -42,7 +42,7 @@ def mail_metadata
           # reduced down to what looks like an email in the received headers
           received_recipients: recipients_from_received_headers,
           meta: {
-            client_id: "email/#{mail.from.first}",
+            client_id: "email/#{from.first}",
             project: handler&.project&.full_path
           }
         }
@@ -78,7 +78,7 @@ def mail_key
       end
 
       def key_from_to_header
-        mail.to.find do |address|
+        to.find do |address|
           key = email_class.key_from_address(address)
           break key if key
         end
@@ -112,6 +112,14 @@ def find_key_from_references
         end
       end
 
+      def from
+        Array(mail.from)
+      end
+
+      def to
+        Array(mail.to)
+      end
+
       def delivered_to
         Array(mail[:delivered_to])
       end

spec/lib/gitlab/email/receiver_spec.rb

@@ -11,6 +11,7 @@
     let_it_be(:project) { create(:project) }
 
     let(:handler) { double(:handler, project: project, execute: true, metrics_event: nil, metrics_params: nil) }
+    let(:client_id) { 'email/jake@example.com' }
 
     it 'correctly finds the mail key' do
       expect(Gitlab::Email::Handler).to receive(:for).with(an_instance_of(Mail::Message), 'gitlabhq/gitlabhq+auth_token').and_return(handler)
@@ -33,7 +34,7 @@
       metadata = receiver.mail_metadata
 
       expect(metadata.keys).to match_array(%i(mail_uid from_address to_address mail_key references delivered_to envelope_to x_envelope_to meta received_recipients))
-      expect(metadata[:meta]).to include(client_id: 'email/jake@example.com', project: project.full_path)
+      expect(metadata[:meta]).to include(client_id: client_id, project: project.full_path)
       expect(metadata[meta_key]).to eq(meta_value)
     end
   end
@@ -126,6 +127,49 @@
     it_behaves_like 'failed receive'
   end
 
+  context "when the email's To field is blank" do
+    before do
+      stub_incoming_email_setting(enabled: true, address: "incoming+%{key}@appmail.example.com")
+    end
+
+    let(:email_raw) do
+      <<~EMAIL
+      Delivered-To: incoming+gitlabhq/gitlabhq+auth_token@appmail.example.com
+      From: "jake@example.com" <jake@example.com>
+      Bcc: "support@example.com" <support@example.com>
+
+      Email content
+      EMAIL
+    end
+
+    let(:meta_key) { :delivered_to }
+    let(:meta_value) { ["incoming+gitlabhq/gitlabhq+auth_token@appmail.example.com"] }
+
+    it_behaves_like 'successful receive'
+  end
+
+  context "when the email's From field is blank" do
+    before do
+      stub_incoming_email_setting(enabled: true, address: "incoming+%{key}@appmail.example.com")
+    end
+
+    let(:email_raw) do
+      <<~EMAIL
+      Delivered-To: incoming+gitlabhq/gitlabhq+auth_token@appmail.example.com
+      To: "support@example.com" <support@example.com>
+
+      Email content
+      EMAIL
+    end
+
+    let(:meta_key) { :delivered_to }
+    let(:meta_value) { ["incoming+gitlabhq/gitlabhq+auth_token@appmail.example.com"] }
+
+    it_behaves_like 'successful receive' do
+      let(:client_id) { 'email/' }
+    end
+  end
+
   context 'when the email was auto generated with X-Autoreply header' do
     let(:email_raw) { fixture_file('emails/auto_reply.eml') }
     let(:expected_error) { Gitlab::Email::AutoGeneratedEmailError }