i18n: Ensure empty strings are consistently translated to `''`.

This changeset fixes an edge case where empty strings were wrongly translated to `'0'` (falsey value) instead of `''` (empty string).

Props Chouby, manooweb, rafiahmedd, lopo.
Fixes #55941.

Built from https://develop.svn.wordpress.org/trunk@54315


git-svn-id: http://core.svn.wordpress.org/trunk@53874 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/pomo/entry.php

@@ -87,10 +87,10 @@ if ( ! class_exists( 'Translation_Entry', false ) ) :
 		/**
 		 * Generates a unique key for this entry.
 		 *
-		 * @return string|false The key or false if the entry is empty.
+		 * @return string|false The key or false if the entry is null.
 		 */
 		public function key() {
-			if ( null === $this->singular || '' === $this->singular ) {
+			if ( null === $this->singular ) {
 				return false;
 			}
 

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-beta1-54314';
+$wp_version = '6.1-beta1-54315';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.