From 5dfd6a02a7c633127ce0207bb2d237614a24111a Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@gmail.com>
Date: Tue, 9 Jun 2015 17:42:28 +0000
Subject: [PATCH] Avoid returning duplicate matches when using a meta query in
 `WP_User_Query`.

A meta_query containing an `OR` relation can result in the same record matching
multiple clauses, leading to duplicate results. The previous prevention against
duplicates [18178] #17582 became unreliable in 4.1 when `WP_Meta_Query`
introduced support for nested clauses. The current changeset adds a new method
`WP_Meta_Query::has_or_relation()` for checking whether an `OR` relation
appears anywhere in the query, and uses the new method in `WP_User_Query` to
enforce distinct results as necessary.

Props maxxsnake.
Fixes #32592.
Built from https://develop.svn.wordpress.org/trunk@32713


git-svn-id: http://core.svn.wordpress.org/trunk@32683 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/meta.php    | 25 +++++++++++++++++++++++++
 wp-includes/user.php    |  2 +-
 wp-includes/version.php |  2 +-
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/wp-includes/meta.php b/wp-includes/meta.php
index ead200455f..d1b74d904a 100644
--- a/wp-includes/meta.php
+++ b/wp-includes/meta.php
@@ -953,6 +953,15 @@ class WP_Meta_Query {
 	 */
 	protected $clauses = array();
 
+	/**
+	 * Whether the query contains any OR relations.
+	 *
+	 * @since 4.3.0
+	 * @access protected
+	 * @var bool
+	 */
+	protected $has_or_relation = false;
+
 	/**
 	 * Constructor.
 	 *
@@ -1046,6 +1055,7 @@ class WP_Meta_Query {
 		// Sanitize the 'relation' key provided in the query.
 		if ( isset( $relation ) && 'OR' === strtoupper( $relation ) ) {
 			$clean_queries['relation'] = 'OR';
+			$this->has_or_relation = true;
 
 		/*
 		 * If there is only a single clause, call the relation 'OR'.
@@ -1578,6 +1588,21 @@ class WP_Meta_Query {
 		 */
 		return apply_filters( 'meta_query_find_compatible_table_alias', $alias, $clause, $parent_query, $this ) ;
 	}
+
+	/**
+	 * Check whether the current query has any OR relations.
+	 *
+	 * In some cases, the presence of an OR relation somewhere in the query will require the use of a DISTINCT or
+	 * GROUP BY keyword in the SELECT clause. The current method can be used in these cases to determine whether
+	 * such a clause is necessary.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @return bool True if the query contains any OR relations, otherwise false.
+	 */
+	public function has_or_relation() {
+		return $this->has_or_relation;
+	}
 }
 
 /**
diff --git a/wp-includes/user.php b/wp-includes/user.php
index 2599ce01a9..cb9695cf7b 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -709,7 +709,7 @@ class WP_User_Query {
 			$this->query_from .= $clauses['join'];
 			$this->query_where .= $clauses['where'];
 
-			if ( 'OR' == $this->meta_query->relation ) {
+			if ( $this->meta_query->has_or_relation() ) {
 				$this->query_fields = 'DISTINCT ' . $this->query_fields;
 			}
 		}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index e3a0247f95..533fdb63ff 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.3-alpha-32712';
+$wp_version = '4.3-alpha-32713';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.