From 28625bfc3824eedfcc2cbf0f8896e23ecc7b1d50 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@gmail.com>
Date: Sat, 3 Oct 2015 20:25:26 +0000
Subject: [PATCH] When creating terms, avoid false dupe checks due to accented
 characters.

`wp_insert_term()` doesn't allow the creation of a term when the term `name`
is the same as another term in the same hierarchy level of the same taxonomy.
Previously, this duplicate check used `get_term_by( 'name' )`, which uses the
database collation to determine sameness. But common collations do not
distinguish between accented and non-accented versions of a character. As a
result, it was impossible to create a term 'Foo' if a sibling term with an
accented character existed.

We address this problem by using `get_terms()` to do the duplicate check. This
query returns all potentially matching terms. We then do a stricter check
for equivalence in PHP, before determining whether one of the matches is
indeed a duplicate.

Props boonebgorges, tyxla, geza.miklo, mehulkaklotar.
Fixes #33864.
Built from https://develop.svn.wordpress.org/trunk@34809


git-svn-id: http://core.svn.wordpress.org/trunk@34774 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/taxonomy-functions.php | 21 ++++++++++++++++++++-
 wp-includes/version.php            |  2 +-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/wp-includes/taxonomy-functions.php b/wp-includes/taxonomy-functions.php
index 8533641a1e..0692f6b833 100644
--- a/wp-includes/taxonomy-functions.php
+++ b/wp-includes/taxonomy-functions.php
@@ -2516,7 +2516,26 @@ function wp_insert_term( $term, $taxonomy, $args = array() ) {
 	 * Prevent the creation of terms with duplicate names at the same level of a taxonomy hierarchy,
 	 * unless a unique slug has been explicitly provided.
 	 */
-	if ( $name_match = get_term_by( 'name', $name, $taxonomy ) ) {
+	$name_matches = get_terms( $taxonomy, array(
+		'name' => $name,
+		'hide_empty' => false,
+	) );
+
+	/*
+	 * The `name` match in `get_terms()` doesn't differentiate accented characters,
+	 * so we do a stricter comparison here.
+	 */
+	$name_match = null;
+	if ( $name_matches ) {
+		foreach ( $name_matches as $_match ) {
+			if ( strtolower( $name ) === strtolower( $_match->name ) ) {
+				$name_match = $_match;
+				break;
+			}
+		}
+	}
+
+	if ( $name_match ) {
 		$slug_match = get_term_by( 'slug', $slug, $taxonomy );
 		if ( ! $slug_provided || $name_match->slug === $slug || $slug_match ) {
 			if ( is_taxonomy_hierarchical( $taxonomy ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 703c632b93..ee45fb830a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.4-alpha-34808';
+$wp_version = '4.4-alpha-34809';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.