From ffa997a3426a811ab68f7c85a1ae9046eb30b94d Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Sat, 3 Oct 2015 21:18:55 +0000
Subject: [PATCH] Update the taxonomy relationship cache in
 `is_object_in_term()`.

This function attempts to read from the relationship cache, and uses any data
it finds. If it finds no data, it does a query for the data it needs. Since we
are going to the trouble to query for the relationships, and since we are
already using cached data when available, let's go ahead and cache it for
later use.

Props joehoyle, boonebgorges.
Fixes #32044.

git-svn-id: https://develop.svn.wordpress.org/trunk@34812 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy-functions.php      |  6 ++-
 tests/phpunit/tests/term/isObjectInTerm.php | 46 +++++++++++++++++++++
 2 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/taxonomy-functions.php b/src/wp-includes/taxonomy-functions.php
index 8de369c2db..7da100b45f 100644
--- a/src/wp-includes/taxonomy-functions.php
+++ b/src/wp-includes/taxonomy-functions.php
@@ -4390,8 +4390,10 @@ function is_object_in_term( $object_id, $taxonomy, $terms = null ) {
 		return new WP_Error( 'invalid_object', __( 'Invalid object ID' ) );
 
 	$object_terms = get_object_term_cache( $object_id, $taxonomy );
-	if ( false === $object_terms )
-		 $object_terms = wp_get_object_terms( $object_id, $taxonomy, array( 'update_term_meta_cache' => false ) );
+	if ( false === $object_terms ) {
+		$object_terms = wp_get_object_terms( $object_id, $taxonomy, array( 'update_term_meta_cache' => false ) );
+		wp_cache_set( $object_id, $object_terms, "{$taxonomy}_relationships" );
+	}
 
 	if ( is_wp_error( $object_terms ) )
 		return $object_terms;
diff --git a/tests/phpunit/tests/term/isObjectInTerm.php b/tests/phpunit/tests/term/isObjectInTerm.php
index d6e2940066..be526aee7d 100644
--- a/tests/phpunit/tests/term/isObjectInTerm.php
+++ b/tests/phpunit/tests/term/isObjectInTerm.php
@@ -100,4 +100,50 @@ class Tests_IsObjectInTerm extends WP_UnitTestCase {
 		wp_set_object_terms( $post_ID, array( $int_tax_name ), 'wptests_tax' );
 		$this->assertTrue( is_object_in_term( $post_ID, 'wptests_tax', $int_tax_name ) );
 	}
+
+	/**
+	 * @ticket 32044
+	 */
+	public function test_should_populate_and_hit_relationships_cache() {
+		global $wpdb;
+
+		register_taxonomy( 'wptests_tax', 'post' );
+		$terms = $this->factory->term->create_many( 2, array( 'taxonomy' => 'wptests_tax' ) );
+
+		$o = 12345;
+		wp_set_object_terms( $o, $terms[0], 'wptests_tax' );
+
+		$num_queries = $wpdb->num_queries;
+		$this->assertTrue( is_object_in_term( $o, 'wptests_tax', $terms[0] ) );
+		$num_queries++;
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+
+		$this->assertFalse( is_object_in_term( $o, 'wptests_tax', $terms[1] ) );
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+	}
+
+	/**
+	 * @ticket 32044
+	 */
+	public function test_should_not_be_fooled_by_a_stale_relationship_cache() {
+		global $wpdb;
+
+		register_taxonomy( 'wptests_tax', 'post' );
+		$terms = $this->factory->term->create_many( 2, array( 'taxonomy' => 'wptests_tax' ) );
+
+		$o = 12345;
+		wp_set_object_terms( $o, $terms[0], 'wptests_tax' );
+
+		$num_queries = $wpdb->num_queries;
+		$this->assertTrue( is_object_in_term( $o, 'wptests_tax', $terms[0] ) );
+		$num_queries++;
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+
+		wp_set_object_terms( $o, $terms[1], 'wptests_tax' );
+
+		$num_queries = $wpdb->num_queries;
+		$this->assertTrue( is_object_in_term( $o, 'wptests_tax', $terms[1] ) );
+		$num_queries++;
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+	}
 }