XML-RPC : Can't remove all the categories from a post by using metaWeblog.editPost

[daniloercoli]

Seems that you can't remove all the categories from a post by calling mw_editPost.
I tried both passing an empty array, or skipping the entry 'categories', in the content struct, but none of them worked. The post still has the previous categories attached to it.

[nacin]

Posts must have at least one category (this is "soft" in core but may be strictly enforced in XML-RPC) — attempting to remove *all* categories without leaving one may be the issue.

[SergeyBiryukov]

This is consistent with how wp_update_post() works.

mw_editPost() fills in $post_category array (line 4507​), then passes it to wp_update_post() (line 4571​). wp_update_post() only overwrites existing post categories if the passed array is not empty: tags/3.6/wp-includes/post.php#L2919​.

[redsweater]

FWIW removing "all" categories for a post works when using mt.setPostCategories, providing an empty array.

nacin's comment about it always being required that there is one category seems to be true, when I remove all categories using this technique, the post acquires the single category "Uncategorized" (default category?) as a result.

[daniloercoli]

Replying to redsweater:

nacin's comment about it always being required that there is one category seems to be true, when I remove all categories using this technique, the post acquires the single category "Uncategorized" (default category?) as a result.

Yes, that's what I was expecting when removing "all" categories for a post.

[SergeyBiryukov]

Related: #26686

[wonderboymusic]

Anyone can patch this