diff --git a/wp-includes/plugin.php b/wp-includes/plugin.php
index dd8798a074..bff15c1383 100644
--- a/wp-includes/plugin.php
+++ b/wp-includes/plugin.php
@@ -946,3 +946,65 @@ function _wp_filter_build_unique_id($tag, $function, $priority) {
 		return $function[0] . '::' . $function[1];
 	}
 }
+
+/**
+ * Back up global variables used for actions and filters.
+ *
+ * Prevents redefinition of these globals in advanced-cache.php from accidentally
+ * destroying existing data.
+ *
+ * @since 4.6.0
+ * @access private
+ *
+ * @global array $wp_filter         Stores all filters and actions.
+ * @global array $wp_actions        Stores the amount of times an action was triggered.
+ * @global array $merged_filters    Merges the filter hooks using this function.
+ * @global array $wp_current_filter Stores the list of current filters with the current one last.
+ * @staticvar array $backup_globals Backed up globals.
+ * @return array the staticvar from the first time it is set.
+ */
+function _backup_plugin_globals(){
+	global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
+	static $backup_globals = array();
+	if ( empty( $backup_globals ) ) {
+		$backup_globals = array(
+			'backup_wp_filter'         => $wp_filter,
+			'backup_wp_actions'        => $wp_actions,
+			'backup_merged_filters'    => $merged_filters,
+			'backup_wp_current_filter' => $wp_current_filter,
+		);
+	};
+	return $backup_globals;
+}
+
+/**
+ * Safely restore backed up global variables used for actions and filters.
+ *
+ * @since 4.6.0
+ * @access private
+ *
+ * @global array $wp_filter         Stores all filters and actions.
+ * @global array $wp_actions        Stores the amount of times an action was triggered.
+ * @global array $merged_filters    Merges the filter hooks using this function.
+ * @global array $wp_current_filter Stores the list of current filters with the current one last.
+ * @staticvar array $backup_globals Backed up globals.
+ */
+function _restore_plugin_globals(){
+	global $wp_filter, $wp_actions, $merged_filters, $wp_current_filter;
+	$backup_globals = _backup_plugin_globals();
+	if ( $wp_filter !== $backup_globals['backup_wp_filter'] ){
+		$wp_filter = array_merge_recursive( $wp_filter, $backup_globals['backup_wp_filter'] );
+	}
+
+	if ( $wp_actions !== $backup_globals['backup_wp_actions'] ){
+		$wp_actions = array_merge_recursive( $wp_actions, $backup_globals['backup_wp_actions'] );
+	}
+
+	if ( $merged_filters !== $backup_globals['backup_merged_filters'] ){
+		$merged_filters = array_merge_recursive( $merged_filters, $backup_globals['backup_merged_filters'] );
+	}
+
+	if ( $wp_current_filter !== $backup_globals['backup_wp_current_filter'] ){
+		$wp_current_filter = array_merge_recursive( $wp_current_filter, $backup_globals['backup_wp_current_filter'] );
+	}
+}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index aba64d6d1d..147167953c 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-alpha-37587';
+$wp_version = '4.6-alpha-37588';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.
diff --git a/wp-settings.php b/wp-settings.php
index fb8cd22d42..8beee6fdb8 100644
--- a/wp-settings.php
+++ b/wp-settings.php
@@ -20,6 +20,7 @@ define( 'WPINC', 'wp-includes' );
 // Include files required for initialization.
 require( ABSPATH . WPINC . '/load.php' );
 require( ABSPATH . WPINC . '/default-constants.php' );
+require( ABSPATH . WPINC . '/plugin.php' );
 
 /*
  * These can't be directly globalized in version.php. When updating,
@@ -70,8 +71,11 @@ timer_start();
 wp_debug_mode();
 
 // For an advanced caching plugin to use. Uses a static drop-in because you would only want one.
-if ( WP_CACHE )
+if ( WP_CACHE ) {
+	_backup_plugin_globals();
 	WP_DEBUG ? include( WP_CONTENT_DIR . '/advanced-cache.php' ) : @include( WP_CONTENT_DIR . '/advanced-cache.php' );
+	_restore_plugin_globals();
+}
 
 // Define WP_LANG_DIR if not set.
 wp_set_lang_dir();
@@ -81,7 +85,6 @@ require( ABSPATH . WPINC . '/compat.php' );
 require( ABSPATH . WPINC . '/functions.php' );
 require( ABSPATH . WPINC . '/class-wp.php' );
 require( ABSPATH . WPINC . '/class-wp-error.php' );
-require( ABSPATH . WPINC . '/plugin.php' );
 require( ABSPATH . WPINC . '/pomo/mo.php' );
 
 // Include the wpdb class and, if present, a db.php database drop-in.