Changeset 38776

Timestamp:

10/11/2016 01:55:58 AM (9 years ago)

Author:

boonebgorges

Message:

Taxonomy: Better error handling when fetching object terms from cache.

Since [37573], get_object_term_cache() has expected term IDs to be
stored in the taxonomy relationship cache. The function would then
reach directly into the 'terms' cache to fetch the data corresponding
to a given term, before returning a WP_Term object. This caused
problems when, for one reason or another, term data was cached
inconsistently:

• If the 'terms' cache is empty for a given term ID, despite the earlier call to _prime_term_caches(), get_term() would return an error object.
• If the array of cached term IDs contains an invalid ID, get_term() would return an error object.

We avoid these errors by no longer touching the 'terms' cache directly,
but running term IDs through get_term() and allowing that function to
reference the cache (and database, as needed). If get_term() returns
an error object for any of the cached term IDs, get_object_term_cache()
will return that error object alone. This change ensures that upstream
functions, like get_the_terms(), return WP_Error objects in a
predictable fashion.

Props dd32, michalzuber.
Fixes #37291.

Location:

trunk

Files:

• src/wp-includes/taxonomy.php (modified) (2 diffs)
• tests/phpunit/tests/term/cache.php (modified) (1 diff)

trunk/src/wp-includes/taxonomy.php

@@ -3011 +3011 @@
  *
  * @since 2.3.0
+ * @since 4.6.2 Returns a WP_Error object if get_term() returns an error for
+ *              any of the matched terms.
  *
  * @param int    $id       Term object ID.
  * @param string $taxonomy Taxonomy name.
- * @return bool|array Array of `WP_Term` objects, if cached False if cache is empty for `$taxonomy` and `$id`.
+ * @return bool|array|WP_Error Array of `WP_Term` objects, if cached.
+ *                             False if cache is empty for `$taxonomy` and `$id`.
+ *                             WP_Error if get_term() returns an error object for any term.
  */
 function get_object_term_cache( $id, $taxonomy ) {
@@ -3039 +3043 @@
     $terms = array();
     foreach ( $term_ids as $term_id ) {
-        $terms[] = wp_cache_get( $term_id, 'terms' );
-    }
-
-    return array_map( 'get_term', $terms );
+        $term = get_term( $term_id );
+        if ( is_wp_error( $term ) ) {
+            return $term;
+        }
+
+        $terms[] = $term;
+    }
+
+    return $terms;
 }
 

trunk/tests/phpunit/tests/term/cache.php

@@ -391 +391 @@
         $this->assertEquals( $num_queries, $wpdb->num_queries );
     }
+
+    /**
+     * @ticket 37291
+     */
+    public function test_get_object_term_cache_should_return_error_if_any_term_is_an_error() {
+        register_taxonomy( 'wptests_tax', 'post' );
+
+        $t = self::factory()->term->create( array( 'taxonomy' => 'wptests_tax' ) );
+        $p = self::factory()->post->create();
+        wp_set_object_terms( $p, $t, 'wptests_tax' );
+
+        // Prime cache.
+        $terms = get_the_terms( $p, 'wptests_tax' );
+        $this->assertEqualSets( array( $t ), wp_list_pluck( $terms, 'term_id' ) );
+
+        /*
+         * Modify cached array to insert an empty term ID,
+         * which will trigger an error in get_term().
+         */
+        $cached_ids = wp_cache_get( $p, 'wptests_tax_relationships' );
+        $cached_ids[] = 0;
+        wp_cache_set( $p, $cached_ids, 'wptests_tax_relationships' );
+
+        $terms = get_the_terms( $p, 'wptests_tax' );
+        $this->assertWPError( $terms );
+    }
 }