Update merge request's merge_commit for branch update

Analyze new commits graph to determine each commit's merge commit.

Fix "merged with [commit]" info for merge requests being merged
automatically by other actions.

Allow analyzing upto the relevant commit

1 files changed, 43 insertions, 0 deletions

diff --git a/spec/lib/gitlab/branch_push_merge_commit_analyzer_spec.rb b/spec/lib/gitlab/branch_push_merge_commit_analyzer_spec.rb
new file mode 100644
index 00000000000..45e182358df
--- /dev/null
+++ b/spec/lib/gitlab/branch_push_merge_commit_analyzer_spec.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::BranchPushMergeCommitAnalyzer do
+  let(:project) { create(:project, :repository) }
+  let(:oldrev) { 'merge-commit-analyze-before' }
+  let(:newrev) { 'merge-commit-analyze-after' }
+  let(:commits) { project.repository.commits_between(oldrev, newrev).reverse }
+
+  subject { described_class.new(commits) }
+
+  describe '#get_merge_commit' do
+    let(:expected_merge_commits) do
+      {
+        '646ece5cfed840eca0a4feb21bcd6a81bb19bda3' => '646ece5cfed840eca0a4feb21bcd6a81bb19bda3',
+        '29284d9bcc350bcae005872d0be6edd016e2efb5' => '29284d9bcc350bcae005872d0be6edd016e2efb5',
+        '5f82584f0a907f3b30cfce5bb8df371454a90051' => '29284d9bcc350bcae005872d0be6edd016e2efb5',
+        '8a994512e8c8f0dfcf22bb16df6e876be7a61036' => '29284d9bcc350bcae005872d0be6edd016e2efb5',
+        '689600b91aabec706e657e38ea706ece1ee8268f' => '29284d9bcc350bcae005872d0be6edd016e2efb5',
+        'db46a1c5a5e474aa169b6cdb7a522d891bc4c5f9' => 'db46a1c5a5e474aa169b6cdb7a522d891bc4c5f9'
+      }
+    end
+
+    it 'returns correct merge commit SHA for each commit' do
+      expected_merge_commits.each do |commit, merge_commit|
+        expect(subject.get_merge_commit(commit)).to eq(merge_commit)
+      end
+    end
+
+    context 'when relevant_commit_ids is provided' do
+      let(:relevant_commit_id) { '8a994512e8c8f0dfcf22bb16df6e876be7a61036' }
+      subject { described_class.new(commits, relevant_commit_ids: [relevant_commit_id]) }
+
+      it 'returns correct merge commit' do
+        expected_merge_commits.each do |commit, merge_commit|
+          subject = described_class.new(commits, relevant_commit_ids: [commit])
+          expect(subject.get_merge_commit(commit)).to eq(merge_commit)
+        end
+      end
+    end
+  end
+end