Ticket #35509: 35509.patch

wp-includes/user.php

@@ -1211 +1211 @@
  * @return int|false The user's ID on success, and false on failure.
  */
 function email_exists( $email ) {
-        if ( $user = get_user_by( 'email', $email) ) {
-                return $user->ID;
+        if ( $user = get_user_by( 'email', $email ) ) {
+
+                /**
+                 * Filter whether the Email exists or not
+                 *
+                 * @since 4.5.0
+                 *
+                 * @param int|false $user_id Email user id.
+                 * @param string $email Email.
+                 */
+
+                return apply_filters( 'email_exists', $user->ID, $email );
         }
-        return false;
+
+        /** This filter is documented in wp-includes/user.php */
+        return apply_filters( 'email_exists', false, $email );
 }
 
 /**