Getting notice is wordpress "WP_Scripts::localize was called incorrectly"

Question

Complete message: Notice: WP_Scripts::localize was called incorrectly. The $l10n parameter must be an array. To pass arbitrary data to scripts, use the wp_add_inline_script() function instead. Please see Debugging in WordPress for more information. (This message was added in version 5.7.0.) in /home3/dduconne/public_html/wp-includes/functions.php on line 5313

Appeared just after updating wordpress to 5.7.0

Answer 1

Ok since there quite a few views and the previous answer just throws it under the rug.

Yes it is a warning now, but who knows what will happen, it is a warning for a reason, disabling something is not resolving it, there is a reason devs set it as a warning for now.

While we wait for plugin developers to resolve it on their ends, you can find out the source of the problem by enabling php_xdebug in php. I recommend not leaving it after debugging, as I am not sure about the performance cost of it being enabled.

php_xdebug will return a stack of all files affected, from there you can trace it to the source of the problem. The fix once found the source is quite easy. Culprit most likely is wp_localize_script() which requires last parameter to be an array()!

So you would find something like this:

wp_localize_script( 'handle', 'object_name', 'l10n_culprit_string' );

Which should be turned into:

wp_localize_script( 'handle', 'object_name', array( 'l10n_culprit_string' ) );

Solution to problem came from here

Answer 2

This is a new warning appearing in Wordpress 5.7. If you don't want to see it, and still want to have WP_DEBUG set to true, it is possible to disable the message by adding the following for example in your theme's functions.php:

 add_filter('doing_it_wrong_trigger_error', function () {return false;}, 10, 0);