My WP always failed when upgrade plugins, I traced it and found it is something about disk io, permission etc. But the problem is it just returns a 500 error without any specific information. I traced it in code and can locate the line of code that gives the exception, but I cannot capture the error. I can put wp_send_json_error before the line to verify it. But try/catch doesn't work, I could not find a way to capture the exception and send the exception info back.

Any idea? thanks