Add support for catching throwables in App/Bootstrap

[DuckThom]

Summary (*)

I noticed that the inner try/catch in the run method in lib/internal/App/Bootstrap.php does not catch throwables. I was wondering if there is any downside in adding a catch for a \Throwable.

Examples (*)

If an error is thrown (for example, a TypeError) it currently shows a browser generic 500 error.

Proposed solution

I would suggest adding the following catch block for minimal changes as a quite a lot of other methods, like the catchException method for example, expect an instance of \Exception, and a TypeError isn't of that type.

catch (\Throwable $e) {
    \Magento\Framework\Profiler::stop('magento');
    $this->objectManager->get(LoggerInterface::class)->error($e->getMessage());

    // Convert the Throwable to an exception to make it compatible with catchException
    $ex = new \Exception($e->getMessage(), $e->getCode(), $e);

    if (!$application->catchException($this, $ex)) {
        throw $ex;
    }
}

[m2-assistant]

Hi @DuckThom. Thank you for your report.
To help us process this issue please make sure that you provided the following information:

• Summary of the issue
• Information on your environment
• Steps to reproduce
• Expected and actual results

Please make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce. To deploy vanilla Magento instance on our environment, please, add a comment to the issue:

@magento give me 2.3-develop instance - upcoming 2.3.x release

For more details, please, review the Magento Contributor Assistant documentation.

@DuckThom do you confirm that you were able to reproduce the issue on vanilla Magento instance following steps to reproduce?

• yes
• no

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[DuckThom]

For quick reference, it's about this line: https://github.com/magento/magento2/blob/2.3-develop/lib/internal/Magento/Framework/App/Bootstrap.php#L269