From dd7e2243fadcb8e21be53fa971954e9ce7cdfec6 Mon Sep 17 00:00:00 2001
From: desrosj <desrosj@git.wordpress.org>
Date: Fri, 14 Dec 2018 03:17:38 +0000
Subject: [PATCH] Meta: Allow empty strings to be set by Custom Fields meta
 box.

Because the REST API allows meta keys to have empty values, the Custom Fields meta box should permit the same behavior.

Props charlestonsw, soulseekah, danielbachhuber.

Merges [43811] to trunk.

Fixes #43559.
Built from https://develop.svn.wordpress.org/trunk@44153


git-svn-id: http://core.svn.wordpress.org/trunk@43983 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/includes/ajax-actions.php | 3 ---
 wp-admin/includes/post.php         | 2 +-
 wp-includes/version.php            | 2 +-
 3 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/wp-admin/includes/ajax-actions.php b/wp-admin/includes/ajax-actions.php
index db22db2924..f11b243e1a 100644
--- a/wp-admin/includes/ajax-actions.php
+++ b/wp-admin/includes/ajax-actions.php
@@ -1443,9 +1443,6 @@ function wp_ajax_add_meta() {
 		if ( '' == trim( $key ) ) {
 			wp_die( __( 'Please provide a custom field name.' ) );
 		}
-		if ( '' == trim( $value ) ) {
-			wp_die( __( 'Please provide a custom field value.' ) );
-		}
 		if ( ! $meta = get_metadata_by_mid( 'post', $mid ) ) {
 			wp_die( 0 ); // if meta doesn't exist
 		}
diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index 2595f69f7c..adc17ba91f 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -867,7 +867,7 @@ function add_meta( $post_ID ) {
 		$metavalue = trim( $metavalue );
 	}
 
-	if ( ( '0' === $metavalue || ! empty( $metavalue ) ) && ( ( ( '#NONE#' != $metakeyselect ) && ! empty( $metakeyselect ) ) || ! empty( $metakeyinput ) ) ) {
+	if ( ( ( '#NONE#' != $metakeyselect ) && ! empty( $metakeyselect ) ) || ! empty( $metakeyinput ) ) {
 		/*
 		 * We have a key/value pair. If both the select and the input
 		 * for the key have data, the input takes precedence.
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 89d468abb1..8c27847531 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44152';
+$wp_version = '5.1-alpha-44153';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.