Taxonomy: Ensure that invalid term objects are discarded in `WP_Term_Query`.

The `get_term()` mapping may result in term objects that are `null` or
`WP_Error` when plugins use `get_term` or a related filter. Since `null`
and error objects are not valid results for a term query, we discard
them.

Props GM_Alex.
See #42691.
Built from https://develop.svn.wordpress.org/trunk@43049


git-svn-id: http://core.svn.wordpress.org/trunk@42878 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-term-query.php

@@ -678,7 +678,7 @@ class WP_Term_Query {
 		$cache        = wp_cache_get( $cache_key, 'terms' );
 		if ( false !== $cache ) {
 			if ( 'all' === $_fields ) {
-				$cache = array_map( 'get_term', $cache );
+				$cache = $this->populate_terms( $cache );
 			}
 
 			$this->terms = $cache;
@@ -810,7 +810,7 @@ class WP_Term_Query {
 		wp_cache_add( $cache_key, $terms, 'terms', DAY_IN_SECONDS );
 
 		if ( 'all' === $_fields || 'all_with_object_id' === $_fields ) {
-			$terms = array_map( 'get_term', $terms );
+			$terms = $this->populate_terms( $terms );
 		}
 
 		$this->terms = $terms;
@@ -972,4 +972,31 @@ class WP_Term_Query {
 
 		return $wpdb->prepare( '((t.name LIKE %s) OR (t.slug LIKE %s))', $like, $like );
 	}
+
+	/**
+	 * Creates an array of term objects from an array of term IDs.
+	 *
+	 * Also discards invalid term objects.
+	 *
+	 * @since 5.0.0
+	 *
+	 * @param array $term_ids Term IDs.
+	 * @return array
+	 */
+	protected function populate_terms( $term_ids ) {
+		$terms = array();
+
+		if ( ! is_array( $term_ids ) ) {
+			return $terms;
+		}
+
+		foreach ( $term_ids as $key => $term_id ) {
+			$term = get_term( $term_id );
+			if ( $term instanceof WP_Term ) {
+				$terms[ $key ] = $term;
+			}
+		}
+
+		return $terms;
+	}
 }

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.0-alpha-43048';
+$wp_version = '5.0-alpha-43049';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.