## WP Ajax Callback being fired twice

Question

I noticed the problem when I was setting up an Ajax action which creates a file with a random name. It always created 2 files with random names.

This is a clean install.

I went ahead and started debugging the core files and realized that everything is called twice. For example, try echoing “ok” in the wp() function in wp-includes/functions.php – it will output “okok” in the front-end.

Is this by design or is there something wrong with the current version of WP?
Is there something I should do to avoid this?

Here are the steps to reproduce:

1 – Add this function to the theme functions.php:

function test() {
fopen("/var/www/html/yourpath/test." . random_int(0, 100000), "w");
die();
}