Implement filters on post_status, check get_post_status() instead of the object's post_status in get_post_permalink()

[misterbisson]

We have some custom post types that we wanted to implement the inherit post_status on, using the pattern created by attachments that allows child posts to inherit their status from the parent. In our case we have a top-level custom post that has a number of children of a different post type, and we wanted to make it easy to publish the entire set simply by publishing the parent.

In implementing this, however, we discovered some hard coded assumptions in get_post_permalink() and get_post_status() that got in our way. Examples:

get_post_status() has specific support for inherit as a post status, but only for attachment post types. Everything else can pound sand. To work around this we added a filter to the return value, which seemed to be both the most compatible and lowest-cost way to implement such a change. It looks like this: return apply_filters( 'get_post_status', $post->post_status, $post );.

And in get_post_permalink() we found that it's checking $post->post_status, making it impossible to ascend the hierarchy and get the status of the parent. The change there was also pretty straightforward: $draft_or_pending = get_post_status( $id ) && in_array( get_post_status( $id ), array( 'draft', 'pending', 'auto-draft' ) );.

I believe this is compatible with #23169 and #23168, which seek to improve support for custom post_statuses. The only other recent ticket/changeset I found mentioning post_status was r22963, which changed from get_post_status( $id ) to $post->post_status for compatible, but opposite reasons.

[misterbisson]

Props @methnen who actually implemented this for testing.

[SergeyBiryukov]

Related: #26365

[antpb]

This looks to have a good use case for inherited custom post type status however the current patch does not include 'future' in the array. I've adjusted the patch to have the future status included. Would like to get a second set of eyes on this as I think it would be useful. Updated patch to follow...

[jorbin]

I like this filter. It helps improve support for custom status, while also being something that is easy to maintain for backwards compatibility.

[obenland]

@jorbin, could you get this committed/punted until beta1 hits next week?

[obenland]

Let's continue this in a future release.

[iamfriendly]

Refreshed the patch and added docs

[iamfriendly]

Refreshed the patch because of the movement of get_post_status() to post-functions.php and added docs for the new filter.

[antpb]

Thank you! @obenland how should this move forward?

[jorbin]

In 35233:

Improve get_post_permalink compatibility with non standard post status

This adds a new filter named get_post_status to the function named get_post_status which can be used to make additional post types behave like unpublished post status in get_post_permalink.

Props misterbisson, antpb, iamfriendly
Fixes #23458

[DrewAPicture]

In 35240:

Docs: Improve the hook doc for the get_post_status filter, introduced in [35233].

Also adds a missing parameter description for $post.

See #23458. See #32246.