[wp-trac] [WordPress Trac] #50641: Everything is being called twice

[WordPress Trac]

#50641: Everything is being called twice
----------------------------+--------------------------
 Reporter:  luciano_mb      |       Owner:  (none)
     Type:  defect (bug)    |      Status:  closed
 Priority:  normal          |   Milestone:
Component:  Bootstrap/Load  |     Version:  5.4.2
 Severity:  normal          |  Resolution:  invalid
 Keywords:                  |     Focuses:  performance
----------------------------+--------------------------
Changes (by SergeyBiryukov):

 * severity:  critical => normal
 * milestone:  Awaiting Review =>


Old description:

> 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?
>
> Thank you.
>
> 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();
> }
> add_action('wp_ajax_test', 'test');
>
> 2 - Access the URL: /wp-admin/admin-ajax.php?action=test
>
> 3 - Check your directory to see 2 different files were created

New description:

 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?

 Thank you.

 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();
 }
 add_action('wp_ajax_test', 'test');
 }}}
 2 - Access the URL: /wp-admin/admin-ajax.php?action=test

 3 - Check your directory to see 2 different files were created

--

Comment:

 Hi there, welcome to WordPress Trac! Thanks for the ticket.

 For reference, I could not reproduce the issue with the steps provided,
 only one file was created on my install.

 Similar issues are generally caused by browser prefetching, see #12603,
 #14382, #19018, #20192, #21658, #28797, #32290, #45108. Some browsers
 automatically load any `<link>` elements with `rel="next"` or
 `rel="prefetch"`.

 So it doesn't look like there's a bug here.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/50641#comment:2>
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