Public custom post status cannot be embedded

[goaroundagain]

Currently it is not possible to embend any post with a custom post status, even when the custom post status is set to

'public' => true

From register_post_status: ​https://codex.wordpress.org/Function_Reference/register_post_status
public: (bool) (optional) Whether posts of this status should be shown in the front end of the site.

For this reason, all post with a custom post status set to public should be embeddable.

The reason why thats not possible is in get_oembed_response_data: ​https://developer.wordpress.org/reference/functions/get_oembed_response_data/

if ( 'publish' !== get_post_status( $post ) ) {
    return false;
}

It just checks if the post status is "publish" and not if "public" on the post status object is set to "true".

To support custom public post status, this could be a solution:

if ( true !== get_post_status_object( get_post_status( $post ) )->public ) {
    return false;
}

Another possibility would be to provide a custom filter:

if ( true !== in_array( get_post_status( $post ), apply_filters( 'oembed_post_status', array( 'publish' ) ) ) {
    return false;
}

[goaroundagain]

Now with unit tests

[goaroundagain]

If the post status is not registered, treat it as a nonpublic

[SergeyBiryukov]

Related: #47911

[davidbaumwald]

@SergeyBiryukov Is this one going to make it in time for 5.3 RC1?