From c2bea27bfdd83a9b1e9ad9b601e6c0f60eedde55 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Fri, 17 Oct 2014 20:58:48 +0000
Subject: [PATCH] Invalidate cache for child terms when parent term is deleted.

Props socki03.
Fixes #29911.

git-svn-id: https://develop.svn.wordpress.org/trunk@29945 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy.php |  7 ++++++-
 tests/phpunit/tests/term.php | 27 +++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index dcf1b56b37..2eecfecf7c 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -2414,7 +2414,8 @@ function wp_delete_term( $term, $taxonomy, $args = array() ) {
 			return $term_obj;
 		$parent = $term_obj->parent;
 
-		$edit_tt_ids = $wpdb->get_col( "SELECT `term_taxonomy_id` FROM $wpdb->term_taxonomy WHERE `parent` = " . (int)$term_obj->term_id );
+		$edit_ids = $wpdb->get_results( "SELECT term_id, term_taxonomy_id FROM $wpdb->term_taxonomy WHERE `parent` = " . (int)$term_obj->term_id );
+		$edit_tt_ids = wp_list_pluck( $edit_ids, 'term_taxonomy_id' );
 
 		/**
 		 * Fires immediately before a term to delete's children are reassigned a parent.
@@ -2426,6 +2427,10 @@ function wp_delete_term( $term, $taxonomy, $args = array() ) {
 		do_action( 'edit_term_taxonomies', $edit_tt_ids );
 		$wpdb->update( $wpdb->term_taxonomy, compact( 'parent' ), array( 'parent' => $term_obj->term_id) + compact( 'taxonomy' ) );
 
+		// Clean the cache for all child terms.
+		$edit_term_ids = wp_list_pluck( $edit_ids, 'term_id' );
+		clean_term_cache( $edit_term_ids, $taxonomy );
+
 		/**
 		 * Fires immediately after a term to delete's children are reassigned a parent.
 		 *
diff --git a/tests/phpunit/tests/term.php b/tests/phpunit/tests/term.php
index 07d57106d7..5ec9b246cd 100644
--- a/tests/phpunit/tests/term.php
+++ b/tests/phpunit/tests/term.php
@@ -1006,6 +1006,33 @@ class Tests_Term extends WP_UnitTestCase {
 		$this->assertTrue( in_array( $found['term_id'], $cached_children[ $t2 ] ) );
 	}
 
+	/**
+	 * @ticket 29911
+	 */
+	public function test_wp_delete_term_should_invalidate_cache_for_child_terms() {
+		register_taxonomy( 'wptests_tax', 'post', array(
+			'hierarchical' => true,
+		) );
+
+		$parent = $this->factory->term->create( array(
+			'taxonomy' => 'wptests_tax',
+		) );
+
+		$child = $this->factory->term->create( array(
+			'taxonomy' => 'wptests_tax',
+			'parent' => $parent,
+			'slug' => 'foo',
+		) );
+
+		// Prime the cache.
+		$child_term = get_term( $child, 'wptests_tax' );
+		$this->assertSame( $parent, $child_term->parent );
+
+		wp_delete_term( $parent, 'wptests_tax' );
+		$child_term = get_term( $child, 'wptests_tax' );
+		$this->assertSame( 0, $child_term->parent );
+	}
+
 	/**
 	 * @ticket 5381
 	 */