Dont change state if we are already in the unchecked merge state

MR: gitlab.com/gitlab-org/gitlab/-/merge_requests/53537
Issue: gitlab.com/gitlab-org/gitlab/-/issues/218410

app/models/merge_request.rb

@@ -196,8 +196,8 @@ class MergeRequest < ApplicationRecord
     end
 
     event :mark_as_unchecked do
-      transition [:preparing, :can_be_merged, :checking, :unchecked] => :unchecked
-      transition [:cannot_be_merged, :cannot_be_merged_rechecking, :cannot_be_merged_recheck] => :cannot_be_merged_recheck
+      transition [:preparing, :can_be_merged, :checking] => :unchecked
+      transition [:cannot_be_merged, :cannot_be_merged_rechecking] => :cannot_be_merged_recheck
     end
 
     event :mark_as_checking do
@@ -326,7 +326,7 @@ class MergeRequest < ApplicationRecord
   scope :preload_approved_by_users, -> { preload(:approved_by_users) }
   scope :preload_metrics, -> (relation) { preload(metrics: relation) }
   scope :preload_project_and_latest_diff, -> { preload(:source_project, :latest_merge_request_diff) }
-  scope :preload_latest_diff_comment, -> { preload(latest_merge_request_diff: :merge_request_diff_commits) }
+  scope :preload_latest_diff_commit, -> { preload(latest_merge_request_diff: :merge_request_diff_commits) }
   scope :with_web_entity_associations, -> { preload(:author, :target_project) }
 
   scope :with_auto_merge_enabled, -> do

app/services/merge_requests/refresh_service.rb

@@ -75,7 +75,7 @@ module MergeRequests
       commit_ids = @commits.map(&:id)
       merge_requests = @project.merge_requests.opened
         .preload_project_and_latest_diff
-        .preload_latest_diff_comment
+        .preload_latest_diff_commit
         .where(target_branch: @push.branch_name).to_a
         .select(&:diff_head_commit)
         .select do |merge_request|

changelogs/unreleased/test_update_merge_request_worker_performance_2.yml

+---
+title: Remove unneeded transitions on MR for mark_as_unchecked event
+merge_request: 53537
+author:
+type: performance

spec/lib/gitlab/git/push_spec.rb

@@ -87,7 +87,7 @@ RSpec.describe Gitlab::Git::Push do
       it { is_expected.to be_force_push }
     end
 
-    context 'when called muiltiple times' do
+    context 'when called mulitiple times' do
       it 'does not make make multiple calls to the force push check' do
         expect(Gitlab::Checks::ForcePush).to receive(:force_push?).once
 

spec/models/merge_request_spec.rb

@@ -4105,6 +4105,72 @@ RSpec.describe MergeRequest, factory_default: :keep do
       end
     end
 
+    describe '#mark_as_unchecked' do
+      subject { create(:merge_request, source_project: project, merge_status: merge_status) }
+
+      shared_examples 'for an invalid state transition' do
+        it 'is not a valid state transition' do
+          expect { subject.mark_as_unchecked! }.to raise_error(StateMachines::InvalidTransition)
+        end
+      end
+
+      shared_examples 'for an valid state transition' do
+        it 'is a valid state transition' do
+          expect { subject.mark_as_unchecked! }
+            .to change { subject.merge_status }
+            .from(merge_status.to_s)
+            .to(expected_merge_status)
+        end
+      end
+
+      context 'when the status is unchecked' do
+        let(:merge_status) { :unchecked }
+
+        include_examples 'for an invalid state transition'
+      end
+
+      context 'when the status is checking' do
+        let(:merge_status) { :checking }
+        let(:expected_merge_status) { 'unchecked' }
+
+        include_examples 'for an valid state transition'
+      end
+
+      context 'when the status is preparing' do
+        let(:merge_status) { :preparing }
+        let(:expected_merge_status) { 'unchecked' }
+
+        include_examples 'for an valid state transition'
+      end
+
+      context 'when the status is can_be_merged' do
+        let(:merge_status) { :can_be_merged }
+        let(:expected_merge_status) { 'unchecked' }
+
+        include_examples 'for an valid state transition'
+      end
+
+      context 'when the status is cannot_be_merged_recheck' do
+        let(:merge_status) { :cannot_be_merged_recheck }
+
+        include_examples 'for an invalid state transition'
+      end
+
+      context 'when the status is cannot_be_merged' do
+        let(:merge_status) { :cannot_be_merged }
+        let(:expected_merge_status) { 'cannot_be_merged_recheck' }
+
+        include_examples 'for an valid state transition'
+      end
+
+      context 'when the status is cannot_be_merged' do
+        let(:merge_status) { :cannot_be_merged }
+        let(:expected_merge_status) { 'cannot_be_merged_recheck' }
+
+        include_examples 'for an valid state transition'
+      end
+    end
+
     describe 'transition to cannot_be_merged' do
       let(:notification_service) { double(:notification_service) }
       let(:todo_service) { double(:todo_service) }