wp_insert_post overwrites categories when updating existing post

[markoheijnen]

When creating an post object with get_default_post_to_edit(), wp_insert_post() will ignored the set category.
It doesn't look if the post has already a good category.

[markoheijnen]

Does fix the issue. Maybe need better formating

[hughwillfayle]

Why should this be? WordPress sets category to the default one if there hasn't been setted one.

[nacin]

Could we have some example code that triggers this?

Is this an issue to fix/benefit XML-RPC changes in 3.4 at this point?

[markoheijnen]

I don't believe it is xml-rpc related. What I did was adding the category with the metod wp_set_object_terms() on the post ID what you get from get_default_post_to_edit(). I know thisis a rare condition.

[markoheijnen]

#22220 was marked as a duplicate.

[leewillis77]

Patch

[leewillis77]

Hi;

I just hit this bug in a project. The issue is that if you call wp_insert_post() with an existing post ID, and do not supply post_category then any categories assigned to the post will be removed and replaced with the default category.

Patch with unit tests attached.

Trac ticket:

[desrosj]

Looks like this still exists today.

Since it has not had any activity in 6+ years, I'm resetting the Owned by field. If anyone that has participated in the past would like to reclaim it, please feel free.

I've refreshed 19954.diff​ to apply to the current trunk and adjusted the approach slightly. The coverage of this area in wp_insert_post() is ​actually quite good. With the added tests, I think this is a pretty safe change to make, but would still like some additional testing and sanity checking.

[johnbillion]

In 53883:

Posts, Post Types: Prevent categories from being overwritten when updating a post using wp_insert_post().

This prevents existing category relationships being overridden with the default category when none is provided in the post data.

Props markoheijnen, leewillis77, desrosj

Fixes #19954

https://core.trac.wordpress.org/changeset/53883