Don't assume the $post is an array in sanitize_post().

[morganestes]

sanitize_post() expects $post to be an object (OBJECT|WP_Post) or an array (ARRAY_A|ARRAY_N), and returns the same type, but only checks for is_object(), then assumes it's an array and iterates over it as one without further checking.

It may be a bit overkill, but explicitly checking for is_array() seems like the right thing to do to avoid potential errors thrown by trying to use array_keys() over a non-array.

[morganestes]

Add explicit check for an array before trying to access keys.

[wonderboymusic]

In 34080:

sanitize_post() is polymorphic, add an is_array() check for $post before operating on it as an array.

Props morganestes.
Fixes #33118.

[kitchin]

Seems to me there should be an else $post = null if this is a sanitization function.

[morganestes]

Replying to kitchin:

Seems to me there should be an else $post = null if this is a sanitization function.

I don't think completely changing the expected return type by nullifying it is the way to go here, but I could see throwing a 'doing_it_wrong' early if fails a type check.