Pass by reference in wp_get_object_terms()

[stephenharris]

Hi, I've noticed a bug in the current beta version: 3.8-beta-1-26375. I've tracked it down to this patch: ​http://core.trac.wordpress.org/attachment/ticket/17646/17646.3.diff (#17646).

Each term in the foreach of the $terms array is passed by reference when sanitising the term. However, this is not unset after the foreach loop.

As such the seemly innocuous code changes the last term from an object to an integer:

add_filter( 'wp_get_object_terms', 'my_get_object_terms_callback' );
function my_get_object_terms_callback( $terms ){

	// var_dump reveals an array of objects

	$term_ids = wp_list_pluck( $terms, 'term_id' );

	// last term is now an integer

	return $terms;
}

( I'm aware wp_get_object_terms filter isn't necessarily filtering term objects, but this highlights the bug).

[stephenharris]

Unset references after foreach loop

[SergeyBiryukov]

Introduced in [26010].

[stephenharris]

Assign by key rather than by reference

[stephenharris]

I've added an alternative patch which assigns by key rather than reference (which in my opinion is a bit more pretty).

[SergeyBiryukov]

26339-2.diff​ looks good to me. A unit test would be nice.

[wonderboymusic]

In 26510:

Fix lingering reference problem in wp_get_object_terms() by not setting the foreach'd vars to a reference. Adds unit test.

Props stephenharris.
Fixes #26339.