get_post_permalink tries is_wp_error on get_post which it will never be

[renegeuze]

get_post_permalink incorrectly calls is_wp_error on the result of get_post($id). Instead it should check for !($post instanceof \WP_Post) or just $post === false, since at this location it won't ever be an array either.

Documentation is wrong too - but I assume that's generated from docBlock.

To reproduce: get_post_permalink('whatever-argument-that-does-not-resolve-an-existing-post');
Expected result: return false(or an actual WP_Error but other code like get_permalink() does not expect it)

[SergeyBiryukov]

Hi there, welcome to WordPress Trac!

Thanks for the ticket, sorry it took so long for someone to get back to you.

Found this while working on #56243, still appears to be a valid issue.

[SergeyBiryukov]

In 53733:

Posts, Post Types: Correct the check for non-existing post in get_post_permalink().

The function was erroneously calling is_wp_error() on the result of a get_post() call, which returns null on failure, and never returns a WP_Error object.

Previously, passing a non-existing post ID to the function would result in a home URL being returned and a few Attempt to read property "post_type, post_name, hierarchical..." on null PHP warnings.

This commit ensures get_post_permalink() returns false on failure, which brings parity with get_permalink().

Includes a unit test to confirm the correct behavior.

Follow-up to [12923], [13023], [32606].

Props renegeuze, manzoorwani.jk.
Fixes #45329.

[SergeyBiryukov]

In 53734:

Docs: Add a @since note for get_post_permalink() returning false on failure.

Follow-up to [53733].

See #45329.

[peterwilsoncc]

A call out for this on the other developer focused changed dev-note would be helpful.