Improve wp_list_categories to support multiple taxonomies

[bordoni]

Hi folks, I was working on a plugin feature request and from what I see it's not possible to pass an array on the taxonomy param from wp_list_categories, which prevents multiple taxonomies to be fetched at once.

I wanted to know if I can work on this "enhancement" for version 4.4, should be an easy modification since get_terms is an easy replacement for get_categories.

[talldanwp]

Hi @bordoni, thanks for creating the ticket and apologies it took such a long time to receive a response.

The ticket was discussed in a triage meeting in slack (viewing the conversation will require a Making WordPress slack account - ​https://wordpress.slack.com/archives/C02RQBWTW/p1591247379036400).

There were a few points noted in the meeting:

• A way forward might be to introduce a new wp_list_terms function for listing terms generically. wp_list_categories could then be re-written to use wp_list_terms.
• The current_category param was changed in 4.4 to accept an array, so there is some precedent for this kind of change.
• Unit tests should be added for this change.

[SergeyBiryukov]

wp_list_categories() was indeed added in WordPress 2.1, but taxonomies were only introduced in 2.3, adjusting the version accordingly.