The shortcode content is expected to be a string, not `null`. `do_shortcode()` expects a string for `$content`.
The `img_caption_shortcode()` also expects a string for the `$content` parameter and is expected to return a string for the HTML content to display the caption.
Prior to this commit:
The default value for the `$content` parameter was set to `null`. If no `$content` was passed, the function:
- could return `null` when the `$atts['width'] < 1` or there was no caption
- else, it invoked `do_shortcode( $content )` passing `null` which on PHP 8.1+ triggers a deprecation notice:
{{{
strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated
}}}
This commit:
- Fixes the default `$content` value to align to the expected shortcode content of `string`, not `null`.
- Fixes the PHP 8.1 deprecation notice when `null` was being passed to `do_shortcode()`.
- Changes the assertion in a couple of tests to check for the empty string instead of `null.
Follow-up to [8196], [8925], [8239], [26915], [31530], [42704].
Props jrf, hellofromTonya, azaozz, joedolson.
See #53635.
git-svn-id: https://develop.svn.wordpress.org/trunk@51816 602fd350-edb4-49c9-b593-d223f7449a82
c0b328a74d