Handle Runner::Error::RunnerInUse during file copy

When the runner is already in use, we do not want to request a new runner or try copying files again. Hence, this improvement is needed to avoid an invalid state or other errors.

Author: MrSerth

app/models/runner.rb

@@ -46,12 +46,15 @@ def self.for(contributor, execution_environment)
   def copy_files(files)
     reserve!
     @strategy.copy_files(files)
+    release!
+  rescue Runner::Error::RunnerInUse => e
+    Rails.logger.debug { "Copying files failed because the runner was already in use: #{e.message}" }
+    raise e
   rescue Runner::Error => e
     Sentry.capture_exception(e) unless e.is_a? Runner::Error::RunnerNotFound
     request_new_id
     save
     @strategy.copy_files(files)
-  ensure
     release!
   end