Memoize force_push when updating a merge request

Merge Request: gitlab.com/gitlab-org/gitlab/-/merge_requests/53536
Issue: gitlab.com/gitlab-org/gitlab/-/issues/218410

changelogs/unreleased/test_update_merge_request_worker_performance.yml

+---
+title: Speed up update merge request worker by memoizing whether a push is a force or not
+merge_request: 53536
+author:
+type: performance

lib/gitlab/git/push.rb

@@ -33,7 +33,9 @@ module Gitlab
       end
 
       def force_push?
-        Gitlab::Checks::ForcePush.force_push?(@project, @oldrev, @newrev)
+        strong_memoize(:force_push) do
+          Gitlab::Checks::ForcePush.force_push?(@project, @oldrev, @newrev)
+        end
       end
 
       def branch_push?

spec/lib/gitlab/git/push_spec.rb

@@ -86,6 +86,16 @@ RSpec.describe Gitlab::Git::Push do
 
       it { is_expected.to be_force_push }
     end
+
+    context 'when called muiltiple times' do
+      it 'does not make make multiple calls to the force push check' do
+        expect(Gitlab::Checks::ForcePush).to receive(:force_push?).once
+
+        2.times do
+          subject.force_push?
+        end
+      end
+    end
   end
 
   describe '#branch_added?' do