Categories revert to default when scheduled posts are published

[danielbachhuber]

The issue is that a scheduled post's categories are dropped when it's published. check_and_publish_future_post() calls wp_publish_post():

http://core.trac.wordpress.org/browser/trunk/wp-includes/post.php#L2882

which, in turn, gets a WP_Post object, changes the status, can calls wp_insert_post():

http://core.trac.wordpress.org/browser/trunk/wp-includes/post.php#L2863

but, because post_category isn't a part of the WP_Post object, the categories default to default

r21942 seems to be the culprit. This is reproducible on wpcom and in trunk.

Replaces wp_insert_post() with wp_update_post() and fixes the issue

In [22189]:

Use wp_update_post() rather than wp_insert_post() in wp_publish_post() to avoid stomping of values like categories. props ericmann, fixes #22167. see #21963.