$order object in thankyou.php is empty??

I am using WP 3.8.1 and WC 2.1.2.

PHP 5.3.3, MySQL 5.1, Apache 2.2

In templates/checkout/thankyou.php, there is a statement at the beginning:

if ( $order ) :

However, when I test the checkout in my local machine, the $order object is empty (i.e. not an object) and therefore goes to the next “else” statement.

I am using custom payment gateway, is it the cause of it? If not, what would cause this object to fail?

By the way, after printing get_temp_dir, it is /tmp/, which is accessible (drwxrwxrwt.)

Thank you.

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