Require errorReportingLevel to be a subset of error_reporting

[imjoehaines]

Goal

PHP 8 has changed how the @ operator works:

The @ operator will no longer silence fatal errors (E_ERROR, E_CORE_ERROR, E_COMPILE_ERROR, E_USER_ERROR, E_RECOVERABLE_ERROR, E_PARSE).

https://github.com/php/php-src/blob/7be61bec8037e601c989e5002198f77bf39e8d59/UPGRADING#L59-L82

Previously, error_reporting would return '0' if @ is used but in PHP 8 it can now return any combination of fatal error types, depending on which were enabled (see https://3v4l.org/Z2lfD)

This means that our current check for the @ operator will no longer work so we need an alternative in order to fully support PHP 8. This is made more complicated because we have a second, Bugsnag only error level (errorReportingLevel), otherwise this would be a simple change

Design

Quite a few options were explored, but eventually we decided that the best way to solve this is to require that Bugsnag's errorReportingLevel is a subset of error_reporting — i.e. every error level in errorReportingLevel must also be in error_reporting

This allows us to check if something has been silenced by checking against error_reporting first — if the error code is not in error_reporting then it has either been silenced or was never being reported to begin with

If errorReportingLevel is not a subset of error_reporting, a warning will be logged and all errors of the incorrect level(s) will be ignored

For example, this would be valid usage of errorReportingLevel because everything in errorReportingLevel is also in error_reporting:

error_reporting(E_ALL & ~E_WARNING & ~E_USER_DEPRECATED);
$client->setErrorReportingLevel(E_ALL & ~E_WARNING & ~E_USER_DEPRECATED & ~E_NOTICE & ~E_USER_NOTICE);

However, this would be invalid usage of errorReportingLevel because E_WARNING is not in error_reporting but is in errorReportingLevel:

error_reporting(E_ALL & ~E_WARNING);
$client->setErrorReportingLevel(E_ALL);

As before, setting errorReportingLevel to 0 will ignore all errors and setting it to null (or not setting it at all) will use error_reporting instead

We decided to implement this universally across PHP versions, so that there's not an unexpected change in Bugsnag's behaviour when going from PHP 7 → 8

Changeset

• Configuration::setErrorReportingLevel now validates the given level is a subset of error_reporting
• Configuration::shouldIgnoreErrorCode uses a PHP 8 compatible way to check for @, enabled by the above change
• Additional helper methods added to ErrorTypes
• Set error_reporting to include all error types in PHPUnit config (this previously varied based on PHP/PHPUnit versions)
• Tests for all the above