Fix References header parser for Microsoft Exchange

Microsoft Exchange would append a comma and another
message id into the References header, therefore we'll
need to fallback and parse the header by ourselves.

Closes #26567

1 files changed, 15 insertions, 0 deletions

diff --git a/spec/lib/gitlab/incoming_email_spec.rb b/spec/lib/gitlab/incoming_email_spec.rb
index 1dcf2c0668b..01d0cb6cbd6 100644
--- a/spec/lib/gitlab/incoming_email_spec.rb
+++ b/spec/lib/gitlab/incoming_email_spec.rb
@@ -48,4 +48,19 @@ describe Gitlab::IncomingEmail, lib: true do
       expect(described_class.key_from_fallback_message_id('reply-key@localhost')).to eq('key')
     end
   end
+
+  context 'self.scan_fallback_references' do
+    let(:references) do
+      '<issue_1@localhost>' +
+        ' <reply-59d8df8370b7e95c5a49fbf86aeb2c93@localhost>' +
+        ',<exchange@microsoft.com>'
+    end
+
+    it 'returns reply key' do
+      expect(described_class.scan_fallback_references(references))
+        .to eq(%w[issue_1@localhost
+                  reply-59d8df8370b7e95c5a49fbf86aeb2c93@localhost
+                  exchange@microsoft.com])
+    end
+  end
 end