fix(backend): improve error handling in message-list.php sub-process

[indridieinarsson]

🍰 Pullrequest

PR #1452 introduced a separate process for concurrently loading messages. In my use case, where cypht runs standalone in a docker container (compiled using the official cypht Dockerfile), most error messages and exceptions leave no traces in the logs, even if using the development versions of php.ini (also supplied by the base docker image). This makes it very hard to debug if things go wrong in message_list.php

This PR tries to remedy this by wrapping the entire contents of message_list.php in a try/catch clause, and then piping the resulting error messages to the parent process via stderr. This way, errors in the subprocess leave understandable log entries.

According to my (admittedly quite limited) research, there are negligible performance implications of wrapping the code in a try block, as long as no exceptions are thrown (performance hit of try/catch is supposed to be only due to the cost of handling the exception).