From 47d995c72adf09eda073b37969491f93b1469a5a Mon Sep 17 00:00:00 2001
From: Andrew Nacin <nacin@git.wordpress.org>
Date: Wed, 31 Mar 2010 09:06:11 +0000
Subject: [PATCH] Add blacklist to remove_theme_support(). fixes #12739.

git-svn-id: https://develop.svn.wordpress.org/trunk@13902 602fd350-edb4-49c9-b593-d223f7449a82
---
 wp-includes/theme.php | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index b9365ac14b..68a6b97c92 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -1531,7 +1531,9 @@ function add_editor_style( $stylesheet = 'editor-style.css' ) {
 /**
  * Allows a theme to register its support of a certain feature
  *
- * Must be called in the themes functions.php file to work.
+ * Must be called in the theme's functions.php file to work.
+ * If attached to a hook, it must be after_setup_theme.
+ * The init hook may be too late for some features.
  *
  * @since 2.9.0
  * @param string $feature the feature being added
@@ -1548,15 +1550,25 @@ function add_theme_support( $feature ) {
 /**
  * Allows a theme to de-register its support of a certain feature
  *
- * Must be called in the themes functions.php file to work.
+ * Should be called in the theme's functions.php file. Generally would
+ * be used for child themes to override support from the parent theme.
  *
  * @since 3.0.0
+ * @see add_theme_support()
  * @param string $feature the feature being added
+ * @return bool Whether feature was removed.
  */
 function remove_theme_support( $feature ) {
+	// Blacklist: for internal registrations not used directly by themes.
+	if ( in_array( $feature, array( 'custom-background', 'custom-header', 'editor-style', 'widgets' ) ) )
+		return false;
+
 	global $_wp_theme_features;
 
-	unset($_wp_theme_features[$feature]);
+	if ( ! isset( $_wp_theme_features[$feature] ) )
+		return false;
+	unset( $_wp_theme_features[$feature] );
+	return true;
 }
 
 /**