Remove CR newlines when generating merge commit message from template

lib/gitlab/merge_requests/merge_commit_message.rb

@@ -10,6 +10,7 @@ module Gitlab
         return unless @merge_request.target_project.merge_commit_template.present?
 
         message = @merge_request.target_project.merge_commit_template
+        message = message.delete("\r")
 
         # Remove placeholders that correspond to empty values and are the last word in the line
         # along with all whitespace characters preceding them.

spec/lib/gitlab/merge_requests/merge_commit_message_spec.rb

@@ -183,4 +183,37 @@ RSpec.describe Gitlab::MergeRequests::MergeCommitMessage do
       end
     end
   end
+
+  context 'when project has template with CRLF newlines' do
+    let(:merge_commit_template) do
+      "Merge branch '%{source_branch}' into '%{target_branch}'\r\n\r\n%{title}\r\n\r\n%{description}\r\n\r\nSee merge request %{reference}"
+    end
+
+    it 'converts it to LF newlines' do
+      expect(subject.message).to eq <<~MSG.rstrip
+        Merge branch 'feature' into 'master'
+
+        Bugfix
+
+        Merge Request Description
+        Next line
+
+        See merge request #{merge_request.to_reference(full: true)}
+      MSG
+    end
+
+    context 'when description is empty string' do
+      let(:merge_request_description) { '' }
+
+      it 'skips description placeholder and removes new line characters before it' do
+        expect(subject.message).to eq <<~MSG.rstrip
+          Merge branch 'feature' into 'master'
+
+          Bugfix
+
+          See merge request #{merge_request.to_reference(full: true)}
+        MSG
+      end
+    end
+  end
 end