From 52e1c3eff06766ab4bd1530f576e21daef0311b3 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Thu, 30 Mar 2017 16:55:32 +0000
Subject: [PATCH] Invalidate term query caches when setting or deleting term
 relationships.

Prior to 4.7, term relationships - as set by `wp_set_object_terms()` or
`wp_remove_object_terms()` - did not affect the term query cache. The
introduction of the 'object_ids' parameter in 4.7 means that the query
cache must be aware of object-term relationships. As such, the
'last_changed' incrementor is now invalidated when term relationships
are modified.

This bug only reared its head when delaying term counting, because term
counting performs its own term query cache invalidation.

Merges [40353] to the 4.7 branch.

Props mboynes.
Fixes #40306.


git-svn-id: https://develop.svn.wordpress.org/branches/4.7@40354 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy.php             |  2 +
 tests/phpunit/tests/term/getTheTerms.php | 62 ++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index 991ebce504..b602683ff2 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -2312,6 +2312,7 @@ function wp_set_object_terms( $object_id, $terms, $taxonomy, $append = false ) {
 	}
 
 	wp_cache_delete( $object_id, $taxonomy . '_relationships' );
+	wp_cache_delete( 'last_changed', 'terms' );
 
 	/**
 	 * Fires after an object's terms have been set.
@@ -2406,6 +2407,7 @@ function wp_remove_object_terms( $object_id, $terms, $taxonomy ) {
 		$deleted = $wpdb->query( $wpdb->prepare( "DELETE FROM $wpdb->term_relationships WHERE object_id = %d AND term_taxonomy_id IN ($in_tt_ids)", $object_id ) );
 
 		wp_cache_delete( $object_id, $taxonomy . '_relationships' );
+		wp_cache_delete( 'last_changed', 'terms' );
 
 		/**
 		 * Fires immediately after an object-term relationship is deleted.
diff --git a/tests/phpunit/tests/term/getTheTerms.php b/tests/phpunit/tests/term/getTheTerms.php
index 6a3d4ba5c1..1bffcb6a63 100644
--- a/tests/phpunit/tests/term/getTheTerms.php
+++ b/tests/phpunit/tests/term/getTheTerms.php
@@ -191,4 +191,66 @@ class Tests_Term_GetTheTerms extends WP_UnitTestCase {
 		$this->assertSame( $num_queries, $wpdb->num_queries );
 
 	}
+
+	/**
+	 * @ticket 40306
+	 */
+	public function test_term_cache_should_be_invalidated_on_set_object_terms() {
+		register_taxonomy( 'wptests_tax', 'post' );
+
+		// Temporarily disable term counting, which performs its own cache invalidation.
+		wp_defer_term_counting( true );
+
+		// Create Test Category.
+		$term_id = self::factory()->term->create( array(
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$post_id = self::factory()->post->create();
+
+		// Prime cache.
+		get_the_terms( $post_id, 'wptests_tax' );
+
+		wp_set_object_terms( $post_id, $term_id, 'wptests_tax' );
+
+		$terms = get_the_terms( $post_id, 'wptests_tax' );
+
+		// Re-activate term counting so this doesn't affect other tests.
+		wp_defer_term_counting( false );
+
+		$this->assertTrue( is_array( $terms ) );
+		$this->assertSame( array( $term_id ), wp_list_pluck( $terms, 'term_id' ) );
+	}
+
+	/**
+	 * @ticket 40306
+	 */
+	public function test_term_cache_should_be_invalidated_on_remove_object_terms() {
+		register_taxonomy( 'wptests_tax', 'post' );
+
+		// Create Test Category.
+		$term_ids = self::factory()->term->create_many( 2, array(
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$post_id = self::factory()->post->create();
+
+		wp_set_object_terms( $post_id, $term_ids, 'wptests_tax' );
+
+		// Prime cache.
+		get_the_terms( $post_id, 'wptests_tax' );
+
+		// Temporarily disable term counting, which performs its own cache invalidation.
+		wp_defer_term_counting( true );
+
+		wp_remove_object_terms( $post_id, $term_ids[0], 'wptests_tax' );
+
+		$terms = get_the_terms( $post_id, 'wptests_tax' );
+
+		// Re-activate term counting so this doesn't affect other tests.
+		wp_defer_term_counting( false );
+
+		$this->assertTrue( is_array( $terms ) );
+		$this->assertSame( array( $term_ids[1] ), wp_list_pluck( $terms, 'term_id' ) );
+	}
 }