warnings with php 8.1

[yus0]

With php v8.1 and WordPress v6.5.2 I receive warnings in admin area:

 PHP Deprecated:  str_replace(): Passing null to parameter #3 ($subject) of type 
 array|string is deprecated in /wp-includes/functions.php on line 7241

 PHP Deprecated:  str_replace(): Passing null to parameter #3 ($subject) of type 
 array|string is deprecated in /wp-includes/functions.php on line 2187

 PHP Deprecated:  strip_tags(): Passing null to parameter #1 ($string) of type string is 
 deprecated in \wp-admin\admin-header.php on line 36

They all are easily fixable, so I just hope somebody will add fixes to next update:

​https://prnt.sc/SXP6CYRUswtz
​https://prnt.sc/-XgEBobeohgn
​https://prnt.sc/GiNK_lL4cwxX

[jrf]

@yus0 thank you for your interest in contributing to WordPress.

These warnings need a backtrace to see where they are originate from. In the fast majority of cases, these are caused by plugins passing an incorrect data type to a WP function.

The fixes you propose are incorrect as they hide the errors instead of fixing them in the function calls which are actually causing them.

Suggest: close unless the reporter provides details showing these deprecations can be traced back to function calls within WordPress itself.

[yus0]

I backtraced warnings, all of them are caused by passing null as $parent_slug into the "add_submenu_page" function. It didn't caused any warnings for years, now it treated by replacing null value with a single space character (empty string still causes warnings because of "get_admin_page_title" returns null).

You are right that suggested changes just hides the problem, that can cause critical errors after adding types declaration for fuctions parameters (I hope it will be done soon or late).

[sabernhardt]

#57580 is also about null parameter(s) in the add_submenu_page function.

(My first patch there could have silenced errors too, but plugin authors need to know that null does not work well.)