From 50a96f165ea6ced49a78e6e78368d45289c34a41 Mon Sep 17 00:00:00 2001
From: Scott Taylor <wonderboymusic@git.wordpress.org>
Date: Thu, 6 Feb 2014 01:58:01 +0000
Subject: [PATCH] Regenerate the term hierarchy cache (`{taxonomy}_children`)
 when it is out of sync with the passed taxonomy's `last_changed` value.

Introduces `taxonomy_hierarchy_is_fresh()`, which is only called in `_get_term_hierarchy()`. The taxonomy's `last_changed` value is checked against the value of `wp_cache_get( 'hierarchy_last_changed', $taxonomy )`.

Adds a unit test - `Tests_Term:test_hierachy_invalidation()`.

See [27101], which makes this type of cache invalidation possible.
Fixes #14485.



git-svn-id: https://develop.svn.wordpress.org/trunk@27102 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy.php | 26 +++++++++++++++++++-
 tests/phpunit/tests/term.php | 47 +++++++++++++++++++++++++++++++++++-
 2 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index 297b98d8be..464a00ca3f 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -2948,7 +2948,10 @@ function update_term_cache($terms, $taxonomy = '') {
 function _get_term_hierarchy($taxonomy) {
 	if ( !is_taxonomy_hierarchical($taxonomy) )
 		return array();
-	$children = get_option("{$taxonomy}_children");
+	$children = false;
+	if ( taxonomy_hierarchy_is_fresh( $taxonomy ) ) {
+		$children = get_option("{$taxonomy}_children");
+	}
 
 	if ( is_array($children) )
 		return $children;
@@ -3521,6 +3524,7 @@ function set_taxonomy_last_changed( $taxonomy ) {
 /**
  * Determine if a post's cache for the passed taxonomy
  *  is in sync.
+ * 
  * @since 3.9.0
  *
  * @param int $id
@@ -3535,4 +3539,24 @@ function post_taxonomy_is_fresh( $id, $taxonomy ) {
 		return false;
 	}
 	return true;
+}
+
+/**
+ * Determine if a hierarchy's cache for the passed taxonomy
+ *  is in sync.
+ *
+ * @since 3.9.0
+ *
+ * @param int $id
+ * @param string $taxonomy
+ * @return boolean
+ */
+function taxonomy_hierarchy_is_fresh( $taxonomy ) {
+	$last_changed = get_taxonomy_last_changed( $taxonomy );
+	$hierarchy_last_changed = wp_cache_get( 'hierarchy_last_changed', $taxonomy );
+	if ( ! $hierarchy_last_changed || $last_changed !== $hierarchy_last_changed ) {
+		wp_cache_set( 'hierarchy_last_changed', $last_changed, $taxonomy );
+		return false;
+	}
+	return true;
 }
\ No newline at end of file
diff --git a/tests/phpunit/tests/term.php b/tests/phpunit/tests/term.php
index 5fc16c8d4e..19ffcd0469 100644
--- a/tests/phpunit/tests/term.php
+++ b/tests/phpunit/tests/term.php
@@ -585,7 +585,7 @@ class Tests_Term extends WP_UnitTestCase {
 		$last_changed3 = get_taxonomy_last_changed( 'category' );
 		$this->assertNotEquals( $last_changed2, $last_changed3 );
 	}
-	
+
 	/**
 	 * @ticket 22526
 	 */
@@ -634,4 +634,49 @@ class Tests_Term extends WP_UnitTestCase {
 		$cats2 = get_the_category( $post->ID );
 		$this->assertNotEquals( $term->name, reset( $cats2 )->name );
 	}
+
+	function test_hierachy_invalidation() {
+		$tax = 'burrito';
+		register_taxonomy( $tax, 'post', array( 'hierarchical' => true ) );
+		$this->assertTrue( get_taxonomy( $tax )->hierarchical );
+
+		$step = 1;
+		$parent_id = 0;
+		$children = 0;
+
+		foreach ( range( 1, 99 ) as $i ) {
+			switch ( $step ) {
+			case 1:
+				$parent = wp_insert_term( 'Parent' . $i, $tax );
+				$parent_id = $parent['term_id'];
+				break;
+			case 2:
+				$parent = wp_insert_term( 'Child' . $i, $tax, array( 'parent' => $parent_id ) );
+				$parent_id = $parent['term_id'];
+				$children++;
+				break;
+			case 3:
+				wp_insert_term( 'Grandchild' . $i, $tax, array( 'parent' => $parent_id ) );
+				$parent_id = 0;
+				$children++;
+				break;
+			}
+
+			$terms = get_terms( $tax, array( 'hide_empty' => false ) );
+			$this->assertEquals( $i, count( $terms ) );
+			if ( 1 < $i ) {
+				$hierarchy = _get_term_hierarchy( $tax );
+				$this->assertNotEmpty( $hierarchy );
+				$this->assertEquals( $children, count( $hierarchy, COUNT_RECURSIVE ) - count( $hierarchy ) );
+			}
+
+			if ( $i % 3 === 0 ) {
+				$step = 1;
+			} else {
+				$step++;
+			}
+		}
+
+		_unregister_taxonomy( $tax );
+	}
 }