From e97ab5362bdff70ea200eb71895a29068a1dd668 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@gmail.com>
Date: Tue, 11 Oct 2016 01:56:29 +0000
Subject: [PATCH] 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.
Built from https://develop.svn.wordpress.org/trunk@38776


git-svn-id: http://core.svn.wordpress.org/trunk@38719 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/taxonomy.php | 15 ++++++++++++---
 wp-includes/version.php  |  2 +-
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/wp-includes/taxonomy.php b/wp-includes/taxonomy.php
index 12efa5a995..1995c3b321 100644
--- a/wp-includes/taxonomy.php
+++ b/wp-includes/taxonomy.php
@@ -3010,10 +3010,14 @@ function clean_term_cache($ids, $taxonomy = '', $clean_taxonomy = true) {
  * function only fetches relationship data that is already in the cache.
  *
  * @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 ) {
 	$_term_ids = wp_cache_get( $id, "{$taxonomy}_relationships" );
@@ -3038,10 +3042,15 @@ function get_object_term_cache( $id, $taxonomy ) {
 
 	$terms = array();
 	foreach ( $term_ids as $term_id ) {
-		$terms[] = wp_cache_get( $term_id, 'terms' );
+		$term = get_term( $term_id );
+		if ( is_wp_error( $term ) ) {
+			return $term;
+		}
+
+		$terms[] = $term;
 	}
 
-	return array_map( 'get_term', $terms );
+	return $terms;
 }
 
 /**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 72dff8e6a3..35dfc2f240 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38775';
+$wp_version = '4.7-alpha-38776';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.