Trying to get property of non-object in Wordpress Breadcrumbs

Question

I have this error in my custom breadcrumbs : Notice: Trying to get property of non-object.

This is the code :

    $taxonomy_exists = taxonomy_exists($custom_taxonomy);
    if(empty($last_category) && !empty($custom_taxonomy) && $taxonomy_exists) {

        $taxonomy_terms = get_the_terms( $post, $custom_taxonomy );
        $cat_id = $taxonomy_terms[0]->term_id; // ERROR LINE
        $cat_nicename = $taxonomy_terms[0]->slug; // ERROR LINE
        $cat_link = get_term_link($taxonomy_terms[0]->term_id, $custom_taxonomy); // ERROR LINE
        $cat_name = $taxonomy_terms[0]->name;

    }

How i can solve this problem ?

Answer 1

You need to check if get_the_terms() is actually returning anything. If a post doesn't have terms in that taxonomy, then $taxonomy_terms won't actually have any terms in it. If $taxonomy_terms is empty then $taxonomy_terms[0] won't actually be a term object so trying to access a property on it (->term_id) will throw an error:

$taxonomy_exists = taxonomy_exists($custom_taxonomy);
if(empty($last_category) && !empty($custom_taxonomy) && $taxonomy_exists) {

    $taxonomy_terms = get_the_terms( $post, $custom_taxonomy );

    if ( ! empty( $taxonomy_terms ) ) {
        $cat_id = $taxonomy_terms[0]->term_id; // ERROR LINE
        $cat_nicename = $taxonomy_terms[0]->slug; // ERROR LINE
        $cat_link = get_term_link($taxonomy_terms[0]->term_id, $custom_taxonomy); // ERROR LINE
        $cat_name = $taxonomy_terms[0]->name;
    }
}