Refresh commit count after repository head changes

app/models/project.rb

@@ -1378,6 +1378,7 @@ def change_head(branch)
       repository.raw_repository.write_ref('HEAD', "refs/heads/#{branch}")
       repository.copy_gitattributes(branch)
       repository.after_change_head
+      ProjectCacheWorker.perform_async(self.id, [], [:commit_count])
       reload_default_branch
     else
       errors.add(:base, "Could not change HEAD: branch '#{branch}' does not exist")

app/workers/project_cache_worker.rb

@@ -27,6 +27,7 @@ def perform(project_id, files = [], statistics = [])
   # rubocop: enable CodeReuse/ActiveRecord
 
   def update_statistics(project, statistics = [])
+    return if Gitlab::Database.read_only?
     return unless try_obtain_lease_for(project.id, :update_statistics)
 
     Rails.logger.info("Updating statistics for project #{project.id}")

changelogs/unreleased/refresh-commit-count-after-head-change.yml

+---
+title: Refresh commit count after repository head changes
+merge_request: 26473
+author:
+type: fixed

spec/models/project_spec.rb

@@ -2388,6 +2388,12 @@
       project.change_head(project.default_branch)
     end
 
+    it 'updates commit count' do
+      expect(ProjectCacheWorker).to receive(:perform_async).with(project.id, [], [:commit_count])
+
+      project.change_head(project.default_branch)
+    end
+
     it 'copies the gitattributes' do
       expect(project.repository).to receive(:copy_gitattributes).with(project.default_branch)
       project.change_head(project.default_branch)