From a160be35b1295ad9930d5e2d59d942bddafbd7dd Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Fri, 25 Sep 2015 13:46:36 +0000
Subject: [PATCH] Bust term query cache when modifying term meta.

The 'last_changed' incrementor is used to invalidate the `get_terms()` query
cache. Since `get_terms()` queries may reference 'meta_query', changing term
metadata could change the results of the queries. So we invalidate the cache
on add, delete, and update.

See #10142.

git-svn-id: https://develop.svn.wordpress.org/trunk@34538 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy-functions.php |  27 ++++++-
 tests/phpunit/tests/term/meta.php      | 107 +++++++++++++++++++++++++
 2 files changed, 131 insertions(+), 3 deletions(-)

diff --git a/src/wp-includes/taxonomy-functions.php b/src/wp-includes/taxonomy-functions.php
index 59fc9a0bf1..3d091e9165 100644
--- a/src/wp-includes/taxonomy-functions.php
+++ b/src/wp-includes/taxonomy-functions.php
@@ -1488,7 +1488,14 @@ function get_terms( $taxonomies, $args = '' ) {
  * @return int|bool Meta ID on success, false on failure.
  */
 function add_term_meta( $term_id, $meta_key, $meta_value, $unique = false ) {
-	return add_metadata( 'term', $term_id, $meta_key, $meta_value, $unique );
+	$added = add_metadata( 'term', $term_id, $meta_key, $meta_value, $unique );
+
+	// Bust term query cache.
+	if ( $added ) {
+		wp_cache_set( 'last_changed', microtime(), 'terms' );
+	}
+
+	return $added;
 }
 
 /**
@@ -1502,7 +1509,14 @@ function add_term_meta( $term_id, $meta_key, $meta_value, $unique = false ) {
  * @return bool True on success, false on failure.
  */
 function delete_term_meta( $term_id, $meta_key, $meta_value = '' ) {
-	return delete_metadata( 'term', $term_id, $meta_key, $meta_value );
+	$deleted = delete_metadata( 'term', $term_id, $meta_key, $meta_value );
+
+	// Bust term query cache.
+	if ( $deleted ) {
+		wp_cache_set( 'last_changed', microtime(), 'terms' );
+	}
+
+	return $deleted;
 }
 
 /**
@@ -1536,7 +1550,14 @@ function get_term_meta( $term_id, $key = '', $single = false ) {
  * @return int|bool Meta ID if the key didn't previously exist. True on successful update. False on failure.
  */
 function update_term_meta( $term_id, $meta_key, $meta_value, $prev_value = '' ) {
-	return update_metadata( 'term', $term_id, $meta_key, $meta_value, $prev_value );
+	$updated = update_metadata( 'term', $term_id, $meta_key, $meta_value, $prev_value );
+
+	// Bust term query cache.
+	if ( $updated ) {
+		wp_cache_set( 'last_changed', microtime(), 'terms' );
+	}
+
+	return $updated;
 }
 
 /**
diff --git a/tests/phpunit/tests/term/meta.php b/tests/phpunit/tests/term/meta.php
index bdd4b369e3..7550f3173b 100644
--- a/tests/phpunit/tests/term/meta.php
+++ b/tests/phpunit/tests/term/meta.php
@@ -144,4 +144,111 @@ class Tests_Term_Meta extends WP_UnitTestCase {
 			}
 		}
 	}
+
+	public function test_adding_term_meta_should_bust_get_terms_cache() {
+		$terms = $this->factory->term->create_many( 2, array( 'taxonomy' => 'wptests_tax' ) );
+
+		add_term_meta( $terms[0], 'foo', 'bar' );
+
+		// Prime cache.
+		$found = get_terms( 'wptests_tax', array(
+			'hide_empty' => false,
+			'fields' => 'ids',
+			'meta_query' => array(
+				array(
+					'key' => 'foo',
+					'value' => 'bar',
+				),
+			),
+		) );
+
+		$this->assertEqualSets( array( $terms[0] ), $found );
+
+		add_term_meta( $terms[1], 'foo', 'bar' );
+
+		$found = get_terms( 'wptests_tax', array(
+			'hide_empty' => false,
+			'fields' => 'ids',
+			'meta_query' => array(
+				array(
+					'key' => 'foo',
+					'value' => 'bar',
+				),
+			),
+		) );
+
+		$this->assertEqualSets( array( $terms[0], $terms[1] ), $found );
+	}
+
+	public function test_updating_term_meta_should_bust_get_terms_cache() {
+		$terms = $this->factory->term->create_many( 2, array( 'taxonomy' => 'wptests_tax' ) );
+
+		add_term_meta( $terms[0], 'foo', 'bar' );
+		add_term_meta( $terms[1], 'foo', 'baz' );
+
+		// Prime cache.
+		$found = get_terms( 'wptests_tax', array(
+			'hide_empty' => false,
+			'fields' => 'ids',
+			'meta_query' => array(
+				array(
+					'key' => 'foo',
+					'value' => 'bar',
+				),
+			),
+		) );
+
+		$this->assertEqualSets( array( $terms[0] ), $found );
+
+		update_term_meta( $terms[1], 'foo', 'bar' );
+
+		$found = get_terms( 'wptests_tax', array(
+			'hide_empty' => false,
+			'fields' => 'ids',
+			'meta_query' => array(
+				array(
+					'key' => 'foo',
+					'value' => 'bar',
+				),
+			),
+		) );
+
+		$this->assertEqualSets( array( $terms[0], $terms[1] ), $found );
+	}
+
+	public function test_deleting_term_meta_should_bust_get_terms_cache() {
+		$terms = $this->factory->term->create_many( 2, array( 'taxonomy' => 'wptests_tax' ) );
+
+		add_term_meta( $terms[0], 'foo', 'bar' );
+		add_term_meta( $terms[1], 'foo', 'bar' );
+
+		// Prime cache.
+		$found = get_terms( 'wptests_tax', array(
+			'hide_empty' => false,
+			'fields' => 'ids',
+			'meta_query' => array(
+				array(
+					'key' => 'foo',
+					'value' => 'bar',
+				),
+			),
+		) );
+
+		$this->assertEqualSets( array( $terms[0], $terms[1] ), $found );
+
+		delete_term_meta( $terms[1], 'foo', 'bar' );
+
+		$found = get_terms( 'wptests_tax', array(
+			'hide_empty' => false,
+			'fields' => 'ids',
+			'meta_query' => array(
+				array(
+					'key' => 'foo',
+					'value' => 'bar',
+				),
+			),
+		) );
+
+		$this->assertEqualSets( array( $terms[0] ), $found );
+	}
 }