PHP Warning during sitemap generation

[dd32]

The below error can be encountered during a sitemap render, this happens as the Taxonomy Sitemap provider doesn't expect that get_term_link() might return a WP_Error.

E_WARNING: wp-includes/formatting.php:4309 - ltrim() expects parameter 1 to be string, object given

In this case, WP_Error was returning ambiguous_term_id - Term ID is shared between multiple taxonomies which is actually a second bug here, that the $taxonomy parameter isn't being passed to properly disambiguate the call.

Attached PR fixes this up.

Avoid a PHP warning on taxonomy sitemaps by checking for error conditions, and avoid error conditions by passing the taxonomy through.

As experienced on WordPress.org

Trac ticket: https://core.trac.wordpress.org/ticket/51416

[ravipatel]

short code for a link issue.

[SergeyBiryukov]

In 49137:

Sitemaps: Check the result of get_term_link() when collecting the URLs in WP_Sitemaps_Taxonomies::get_url_list().

This avoids a PHP warning during sitemap generation if get_term_link() returns an error, e.g. due to term ID being shared between multiple taxonomies.

Additionally, pass the $taxonomy argument to get_term_link() to properly disambiguate the call.

Props dd32.
Fixes #51416.

Merged into WP Core in https://core.trac.wordpress.org/changeset/49137