How To Debug Magento Mystery Error on saveOrderAction() When All Debugging Is Enabled and No Error Message?

Question

As title says all Magento debugging is enabled, and in php.ini all debugging is enabled, and mysql debugging is enabled. Error messages show fine in general. I can call for example a method that doesn't exist and it shows the error fine. The issue is: How do you debug an error when nothing is in the response and there is no error message?

I am clicking on place order on checkout and it just loads and then the button shows again, and looking in Chrome network to view the response, and there is none. I have tried debugging with xdebug following the execution, and on $this->getOnepage()->saveOrder() is where it seems like execution stops, but no error message or any clue as to why it doesn't work (like maybe a mysql integrity violation message).

Has this happened to any of you? How did you find the error?

Answer 1

I found a very good way to debug when magento doesn't want to show the error messages. Go to:

app/code/core/Mage/Core/functions.php

& add breakpoints in this function:

function mageCoreErrorHandler($errno, $errstr, $errfile, $errline){
    if (strpos($errstr, 'DateTimeZone::__construct')!==false) {
        // there's no way to distinguish between caught system exceptions and warnings
        return false;

for some reason the error will never show to the page, but if in xdebug you add the breakpoints here it will show you the errors.