From 103da159d520511cc9534d700b119fcb205dc65a Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Tue, 19 Jul 2016 02:12:48 +0000
Subject: [PATCH] Taxonomy: Improve back compat of values passed to
 'terms_clauses' filter.

Prior to the introduction of `WP_Term_Query`, the 'orderby' clause
passed to the 'terms_clauses' filter was prefixed by `ORDER BY`. After
`WP_Term_Query`, this was not the case; `ORDER BY` was added after the
filter. As such, plugins filtering 'terms_clauses' and returning an
'orderby' clause beginning with `ORDER BY` resulted in invalid syntax
when `WP_Term_Query` prepended a second `ORDER BY` keyword to
the clause.

This changeset rearranges the way the 'orderby' clause is built so that
it will be passed to 'terms_clauses' in the previous format.

Fixes #37378.

git-svn-id: https://develop.svn.wordpress.org/trunk@38099 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/class-wp-term-query.php |  6 +++++-
 tests/phpunit/tests/term/query.php      | 22 ++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/wp-includes/class-wp-term-query.php b/src/wp-includes/class-wp-term-query.php
index cfb4474d05..2d3d085af3 100644
--- a/src/wp-includes/class-wp-term-query.php
+++ b/src/wp-includes/class-wp-term-query.php
@@ -384,6 +384,10 @@ class WP_Term_Query {
 		}
 
 		$orderby = $this->parse_orderby( $this->query_vars['orderby'] );
+		if ( $orderby ) {
+			$orderby = "ORDER BY $orderby";
+		}
+
 		$order = $this->parse_order( $this->query_vars['order'] );
 
 		if ( $taxonomies ) {
@@ -618,7 +622,7 @@ class WP_Term_Query {
 
 		$this->sql_clauses['select']  = "SELECT $distinct $fields";
 		$this->sql_clauses['from']    = "FROM $wpdb->terms AS t $join";
-		$this->sql_clauses['orderby'] = $orderby ? "ORDER BY $orderby $order" : '';
+		$this->sql_clauses['orderby'] = $orderby ? "$orderby $order" : '';
 		$this->sql_clauses['limits']  = $limits;
 
 		$this->request = "{$this->sql_clauses['select']} {$this->sql_clauses['from']} {$where} {$this->sql_clauses['orderby']} {$this->sql_clauses['limits']}";
diff --git a/tests/phpunit/tests/term/query.php b/tests/phpunit/tests/term/query.php
index 37dbe48f23..9a5a29583f 100644
--- a/tests/phpunit/tests/term/query.php
+++ b/tests/phpunit/tests/term/query.php
@@ -85,4 +85,26 @@ class Tests_Term_Query extends WP_UnitTestCase {
 		$found = array_map( 'intval', $q->terms );
 		$this->assertSame( array( $terms[1], $terms[0], $terms[2] ), $found );
 	}
+
+	/**
+	 * @ticket 37378
+	 */
+	public function test_order_by_keyword_should_not_be_duplicated_when_filtered() {
+		register_taxonomy( 'wptests_tax', 'post' );
+
+		add_filter( 'terms_clauses', array( $this, 'filter_terms_clauses' ) );
+		$q = new WP_Term_Query( array(
+			'taxonomy' => array( 'wptests_tax' ),
+			'orderby' => 'name',
+		) );
+		remove_filter( 'terms_clauses', array( $this, 'filter_terms_clauses' ) );
+
+		$this->assertContains( 'ORDER BY tt.term_id', $q->request );
+		$this->assertNotContains( 'ORDER BY ORDER BY', $q->request );
+	}
+
+	public function filter_terms_clauses( $clauses ) {
+		$clauses['orderby'] = 'ORDER BY tt.term_id';
+		return $clauses;
+	}
 }