Question

I’ve already learned that you can’t catch PHP Fatal Errors, and your script will terminate about as soon as it hits one. I’m running a large PHP test suite (not PHPUnit, but a custom solution) on a CI server, and want to have the test pass/failures to be reported in JUnit output format.

Since way too many things in PHP are “Fatal Errors”, I don’t want the Fatal Error to end my test run, so my solution was to use forking, something like this:

foreach($tests as $test) {
    $pid = pcntl_fork();
    if ($pid) {
        $test->run();
        $test->write_junit($some_file_name);
    }
    else {
        pcntl_wait($status);
        if ($status) { //fatal error
            // from here we have no data about why it 
            // crashed, since that was in the child's memory
        }
    }
}

My idea was to close the STDERR in the child and have it send it’s standard error to a pipe that the parent can read and save the error data into the JUnit file, but now I don’t know if that’s possible. Can you change the file for STDERR? Basically, what I want to do is like popen but without the exec() step.

Can I get the output of a child process after it died of a PHP Fatal Error?

Answer 1

You can register a shutdown function in the child process and check the last error when it’s called. If there’s an error that matches one of the fatal types (E_ERROR, E_COMPILE_ERROR, E_CORE_ERROR, and E_PARSE), write it into the JUnit file. While you cannot recover from a fatal error, your shutdown function is still called.

Update: As Pacerier points out in the comments, since E_CORE_ERROR is only thrown while the PHP interpreter is bootstrapping itself, it occurs before a shutdown function can be registered and cannot be trapped.