Notice: in canonical.php line 122

[bobbingwide]

Scenario

• Attempted to access a post using ?p=22781
• Post 22781 exists.
• But it has a post type associated with a plugin that's been deactivated.

Expected result

404 page without a notice

Actual result

404 page with the following Notice
Notice: Trying to get property of non-object in wp-includes\canonical.php on line 122

Explanation

The post_type is not registered so this returns null

$post_type_obj = get_post_type_object($redirect_post->post_type);

Proposed solution

Add test on $post_type_obj.

if ( $post_type_obj && $post_type_obj->public && 'auto-draft' != $redirect_post->post_status ) {

Workaround =

Either re-activate the de-activated plugin, or use the correct post ID... I meant to type ?p=22871

[bobbingwide]

Test $post_type_obj before accessing public property

[Hareesh Pillai]

Confirm that the reported issue still remains and the suggested patch resolves it. Refreshing against trunk.

[SergeyBiryukov]

In 49924:

Canonical: Check if the post type exists when attempting a canonical redirect.

This avoids a PHP notice if the post type is no longer registered.

Follow-up to [14595], [35480].

Props bobbingwide, hareesh-pillai.
Fixes #40309.