From 11226f02a8248016d082ca35987bf4d03c8d50e9 Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@gmail.com>
Date: Fri, 1 May 2015 16:38:29 +0000
Subject: [PATCH] Allow metadata to be deleted when meta_value matches 0 or
 '0'.

In `delete_metadata()`, be stricter about when to ignore a falsey value of
`$meta_value`.

For backward compatibility, an empty string for `$meta_value` is equivalent to
`null` or `false`.

Props sc0ttkclark.
Fixes #32224.
Built from https://develop.svn.wordpress.org/trunk@32331


git-svn-id: http://core.svn.wordpress.org/trunk@32302 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/meta.php    | 21 ++++++++++++---------
 wp-includes/version.php |  2 +-
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/wp-includes/meta.php b/wp-includes/meta.php
index b57e761f46..bcfc847e80 100644
--- a/wp-includes/meta.php
+++ b/wp-includes/meta.php
@@ -294,14 +294,17 @@ function update_metadata($meta_type, $object_id, $meta_key, $meta_value, $prev_v
  *
  * @global wpdb $wpdb WordPress database abstraction object.
  *
- * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
- * @param int $object_id ID of the object metadata is for
- * @param string $meta_key Metadata key
- * @param mixed $meta_value Optional. Metadata value. Must be serializable if non-scalar. If specified, only delete metadata entries
- * 		with this value. Otherwise, delete all entries with the specified meta_key.
- * @param bool $delete_all Optional, default is false. If true, delete matching metadata entries
- * 		for all objects, ignoring the specified object_id. Otherwise, only delete matching
- * 		metadata entries for the specified object_id.
+ * @param string $meta_type  Type of object metadata is for (e.g., comment, post, or user)
+ * @param int    $object_id  ID of the object metadata is for
+ * @param string $meta_key   Metadata key
+ * @param mixed  $meta_value Optional. Metadata value. Must be serializable if non-scalar. If specified, only delete
+ *                           metadata entries with this value. Otherwise, delete all entries with the specified meta_key.
+ *                           Pass `null, `false`, or an empty string to skip this check. (For backward compatibility,
+ *                           it is not possible to pass an empty string to delete those entries with an empty string
+ *                           for a value.)
+ * @param bool   $delete_all Optional, default is false. If true, delete matching metadata entries for all objects,
+ *                           ignoring the specified object_id. Otherwise, only delete matching metadata entries for
+ *                           the specified object_id.
  * @return bool True on successful delete, false on failure.
  */
 function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $delete_all = false) {
@@ -356,7 +359,7 @@ function delete_metadata($meta_type, $object_id, $meta_key, $meta_value = '', $d
 	if ( !$delete_all )
 		$query .= $wpdb->prepare(" AND $type_column = %d", $object_id );
 
-	if ( $meta_value )
+	if ( '' !== $meta_value && null !== $meta_value && false !== $meta_value )
 		$query .= $wpdb->prepare(" AND meta_value = %s", $meta_value );
 
 	$meta_ids = $wpdb->get_col( $query );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 2cbebc9a82..54b9775bbe 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.3-alpha-32330';
+$wp_version = '4.3-alpha-32331';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.