Merge branch '20156-rescue-reference-create-due-to-file-lock-exists' into 'master'

Rescue Rugged::OSError (lock exists) when creating references.

Rescue an exception on concurrent scenarios. I was able to create a spec for this, because if you create the lock file before trying to create the reference the reference is created without a problem and the lock file is removed. So IMHO there is a race condition where more than one process is trying to create the same reference at the same time raising the exception, so I just added the patch without specs.

```ruby
    it "attempting to call keep_around when exists a lock does not fail" do
      ref = repository.send(:keep_around_ref_name, sample_commit.id)
      path = File.join(repository.path, ref)
      lock_path = "#{path}.lock"

      FileUtils.mkdir_p(path)
      File.open(lock_path, 'w') { |f| f.write('') }

      begin
        # No exception is raised because the lock file is removed at some point in the process
        repository.keep_around(sample_commit.id)
      ensure
        File.delete(path)
        File.delete(lock_path)
      end
    end
```

See merge request !5497
Signed-off-by: Rémy Coutable <remy@rymai.me>

CHANGELOG

@@ -14,6 +14,7 @@ v 8.10.2 (unreleased)
   - Add ENV variable to skip repository storages validations. !5478
   - Added `*.js.es6 gitlab-language=javascript` to `.gitattributes`. !5486
   - Don't show comment button in gutter of diffs on MR discussion tab. !5493
+  - Rescue Rugged::OSError (lock exists) when creating references. !5497
 
 v 8.10.1
   - Refactor repository storages documentation. !5428

app/models/repository.rb

@@ -211,6 +211,9 @@ class Repository
       rugged.references.create(keep_around_ref_name(sha), sha, force: true)
     rescue Rugged::ReferenceError => ex
       Rails.logger.error "Unable to create keep-around reference for repository #{path}: #{ex}"
+    rescue Rugged::OSError => ex
+      raise unless ex.message =~ /Failed to create locked file/ && ex.message =~ /File exists/
+      Rails.logger.error "Unable to create keep-around reference for repository #{path}: #{ex}"
     end
   end