warning in wp-includes/class.wp-scripts.php:454: Cannot assign an empty string to a string offset

[dpacks]

When sending an empty value to wp_localize_script() a warning is issued stating:
Cannot assign an empty string to a string offset

How to reproduce:
call wp_localize_script() like this:

<?php
wp_localize_script('my_valid_handle', 'my_variable_name', '');

Analysis:
Sending an empty value for a variable is perfectly legit so there is no problem with the input.
The problem lies here: The code at line 449 treats $l10n forcefully as an array but the code at 454 wrongfully assumes $l10n is an array without checking.

[nofearinc]

The wp_localize_script docs treat $l10n as an array, which is why an empty string is not a valid default value. I'm not sure what's the use case for an empty value in general, but have you tested an empty array instead?

[SergeyBiryukov]

Related: #25280, #29722, #51108.

Just noting that passing a string value to wp_localize_script() is now causing a warning in PHP 8.0 Beta 2:

Warning: Only the first byte will be assigned to the string offset in wp-includes/class.wp-scripts.php on line 492

[hellofromTonya]

Per yesterday's scrub conversation in slack, this ticket is part of the 5.6 PHP8 scope. Moving into the milestone.

[jrf]

Duplicate of #29722 ?

[johnbillion]

Duplicate of #29722.