From 69a167688e4279f761fdd13a9366b2aea5e0765a Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Fri, 14 Nov 2014 21:52:23 +0000
Subject: [PATCH] Flush cache for newly created term in `_split_shared_term()`.

The term itself does not have any cached values yet, but in some cases the new
term's taxonomy may need its cached hierarchy to be refreshed as a result of
the term splitting.

Props jorbin.
See #30335.

git-svn-id: https://develop.svn.wordpress.org/trunk@30347 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/taxonomy.php                 | 17 +++++++----
 tests/phpunit/tests/term/splitSharedTerm.php | 32 ++++++++++++++++++++
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/taxonomy.php b/src/wp-includes/taxonomy.php
index 79d04ae81f..fa450e5fea 100644
--- a/src/wp-includes/taxonomy.php
+++ b/src/wp-includes/taxonomy.php
@@ -4096,12 +4096,17 @@ function _split_shared_term( $term_id, $term_taxonomy_id ) {
 	$term_taxonomy = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->term_taxonomy WHERE term_taxonomy_id = %d", $term_taxonomy_id ) );
 	$children_tt_ids = $wpdb->get_col( $wpdb->prepare( "SELECT term_taxonomy_id FROM $wpdb->term_taxonomy WHERE taxonomy = %s AND parent = %d", $term_taxonomy->taxonomy, $term_id ) );
 
-	foreach ( $children_tt_ids as $child_tt_id ) {
-		$wpdb->update( $wpdb->term_taxonomy,
-			array( 'parent' => $new_term_id ),
-			array( 'term_taxonomy_id' => $child_tt_id )
-		);
-		clean_term_cache( $term_id, $term_taxonomy->taxonomy );
+	if ( ! empty( $children_tt_ids ) ) {
+		foreach ( $children_tt_ids as $child_tt_id ) {
+			$wpdb->update( $wpdb->term_taxonomy,
+				array( 'parent' => $new_term_id ),
+				array( 'term_taxonomy_id' => $child_tt_id )
+			);
+			clean_term_cache( $term_id, $term_taxonomy->taxonomy );
+		}
+	} else {
+		// If the term has no children, we must force its taxonomy cache to be rebuilt separately.
+		clean_term_cache( $new_term_id, $term_taxonomy->taxonomy );
 	}
 
 	// Clean the cache for term taxonomies formerly shared with the current term.
diff --git a/tests/phpunit/tests/term/splitSharedTerm.php b/tests/phpunit/tests/term/splitSharedTerm.php
index 50ef1c96c7..ceab947049 100644
--- a/tests/phpunit/tests/term/splitSharedTerm.php
+++ b/tests/phpunit/tests/term/splitSharedTerm.php
@@ -89,4 +89,36 @@ class Tests_Term_SplitSharedTerm extends WP_UnitTestCase {
 
 		$this->assertEquals( $this->tt_ids['t2_child'], $children[0]->term_taxonomy_id );
 	}
+
+	/**
+	 * @ticket 30335
+	 */
+	public function test_should_rebuild_split_term_taxonomy_hierarchy() {
+		global $wpdb;
+
+		register_taxonomy( 'wptests_tax_3', 'post' );
+		register_taxonomy( 'wptests_tax_4', 'post', array(
+			'hierarchical' => true,
+		) );
+
+		$t1 = wp_insert_term( 'Foo1', 'wptests_tax_3' );
+		$t2 = wp_insert_term( 'Foo1 Parent', 'wptests_tax_4' );
+		$t3 = wp_insert_term( 'Foo1', 'wptests_tax_4', array(
+			'parent' => $t2['term_id'],
+		) );
+
+		// Manually modify because split terms shouldn't naturally occur.
+		$wpdb->update( $wpdb->term_taxonomy,
+			array( 'term_id' => $t1['term_id'] ),
+			array( 'term_taxonomy_id' => $t3['term_taxonomy_id'] ),
+			array( '%d' ),
+			array( '%d' )
+		);
+		$th = _get_term_hierarchy( 'wptests_tax_4' );
+
+		$new_term_id = _split_shared_term( $t1['term_id'], $t3['term_taxonomy_id'] );
+
+		$t2_children = get_term_children( $t2['term_id'], 'wptests_tax_4' );
+		$this->assertEquals( array( $new_term_id ), $t2_children );
+	}
 }