[WordPress - 5.1] Can't get categories after publishing the post first time on using "transition_post_status" action

[malayladu]

When we publish the Post for the first time without doing "Save draft" at that time we are not getting post categories in the function which is bind to "transition_post_status" status hook.

We are using "get_the_category" method to get the categories. But, every time it returns default category.

It works when we do "Save draft" and then "Publish" it.

I suspect it's related to WP_REST_Posts_Controller where "wp_update_post" method is called and we are not passing "selected categories" into data and in "wp_update_post" it overwrites post categories with default category if it's not set.

[peterwilsoncc]

Hi @malayladu and welcome to trac!

This is due to the issue detailed in #45114, post meta and terms (tags, categories, custom taxonomies) are not updated until after wp_update_post() runs so the details are not available when saving via the REST API, which the new editor uses.

Some ideas have been presented but a way forward hasn't been decided yet, I am afraid.

I'm marking this ticket as duplicate so discussion can continue in one place on #45114.

[malayladu]

Ok.

Got it.