From 255aaa471e6a3c2090ff44eb65cf31ce860a76d5 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Sat, 25 Jun 2016 16:22:55 +0000
Subject: [PATCH] Fix orderby meta handling for `WP_Term_Query`.

In order to allow meta-related values of `orderby` to be handled properly,
the term query's `meta_query` object must run its `get_sql()` method before
`orderby` parsing.

Fixing this bug required addressing another bug in `WP_Meta_Query`, which
caused the table alias index not to be reset when calling `get_sql()`
multiple times on the same object.

Props littler.chicken.
Fixes #37151.

git-svn-id: https://develop.svn.wordpress.org/trunk@37860 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/class-wp-meta-query.php |  2 ++
 src/wp-includes/class-wp-term-query.php |  2 ++
 tests/phpunit/tests/term/query.php      | 24 ++++++++++++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/src/wp-includes/class-wp-meta-query.php b/src/wp-includes/class-wp-meta-query.php
index affb83af64..4019912019 100644
--- a/src/wp-includes/class-wp-meta-query.php
+++ b/src/wp-includes/class-wp-meta-query.php
@@ -327,6 +327,8 @@ class WP_Meta_Query {
 			return false;
 		}
 
+		$this->table_aliases = array();
+
 		$this->meta_table     = $meta_table;
 		$this->meta_id_column = sanitize_key( $type . '_id' );
 
diff --git a/src/wp-includes/class-wp-term-query.php b/src/wp-includes/class-wp-term-query.php
index 924a1e8c4d..dd42166cfd 100644
--- a/src/wp-includes/class-wp-term-query.php
+++ b/src/wp-includes/class-wp-term-query.php
@@ -814,6 +814,8 @@ class WP_Term_Query {
 	protected function parse_orderby_meta( $orderby_raw ) {
 		$orderby = '';
 
+		// Tell the meta query to generate its SQL, so we have access to table aliases.
+		$this->meta_query->get_sql( 'term', 't', 'term_id' );
 		$meta_clauses = $this->meta_query->get_clauses();
 		if ( ! $meta_clauses || ! $orderby_raw ) {
 			return $orderby;
diff --git a/tests/phpunit/tests/term/query.php b/tests/phpunit/tests/term/query.php
index d1f875bcaa..37dbe48f23 100644
--- a/tests/phpunit/tests/term/query.php
+++ b/tests/phpunit/tests/term/query.php
@@ -61,4 +61,28 @@ class Tests_Term_Query extends WP_UnitTestCase {
 
 		$this->assertEqualSets( array( $terms[0], $terms[2] ), $q->terms );
 	}
+
+	/**
+	 * @ticket 37151
+	 */
+	public function test_order_by_meta_value_num() {
+		register_taxonomy( 'wptests_tax', 'post' );
+
+		$terms = self::factory()->term->create_many( 3, array( 'taxonomy' => 'wptests_tax' ) );
+
+		add_term_meta( $terms[0], 'foo', 10 );
+		add_term_meta( $terms[1], 'foo', 1 );
+		add_term_meta( $terms[2], 'foo', 100 );
+
+		$q = new WP_Term_Query( array(
+			'taxonomy' => array( 'wptests_tax' ),
+			'fields' => 'ids',
+			'hide_empty' => false,
+			'meta_key' => 'foo',
+			'orderby' => 'meta_value_num',
+		) );
+
+		$found = array_map( 'intval', $q->terms );
+		$this->assertSame( array( $terms[1], $terms[0], $terms[2] ), $found );
+	}
 }