debug_backtrace() from registered shutdown function in PHP

Is there any way to circumvent this, forcing PHP to hold the stack trace

That's rather meaningless, when the registered function is invoked, all your defined functions have returned or been cleared down from the stack.

If you need to know where your code exited, then you need to instrument your code.

This is a very expensive solution. I never used register_tick_function() or tick and I'm not sure if it works as expected.

declare(ticks=1);

function tick_handler() {
    global $backtrace;
    $backtrace = debug_backtrace();
}
register_tick_function('tick_handler');



function shutdown() {
    global $backtrace;
    // do check if $backtrace contains a fatal error...
    var_dump($backtrace);
}
register_shutdown_function('shutdown');

In XDebug extension, there is a xdebug_get_function_stack() function.

This one works similar to PHP's internal debug_backtrace(), but keeps the trace even in shutdown handler.

You won't get the exact exit point though, only the last executed function before the shutdown occured (triggered by die()/exit() call or error).

This is of course suitable only for development environment.