From 2ed703ed788073c2458b5e7f12293c3a9f953b48 Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Thu, 5 Jan 2017 07:13:42 +0000
Subject: [PATCH] Customize: Ensure `theme_mod`-cache of `custom_css` lookup of
 `-1` short-circuits a `WP_Query` from being made.

Props dlh.
See #35395.
Fixes #39259.

Built from https://develop.svn.wordpress.org/trunk@39688


git-svn-id: http://core.svn.wordpress.org/trunk@39628 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/theme.php   | 25 +++++++++++++++----------
 wp-includes/version.php |  2 +-
 2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index 47194dfcc7..24fa1116cf 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -1653,18 +1653,17 @@ function wp_get_custom_css_post( $stylesheet = '' ) {
 
 		if ( $post_id > 0 && get_post( $post_id ) ) {
 			$post = get_post( $post_id );
-		} else {
+		}
+
+		// `-1` indicates no post exists; no query necessary.
+		if ( ! $post && -1 !== $post_id ) {
 			$query = new WP_Query( $custom_css_query_vars );
 			$post = $query->post;
 			/*
-			 * Cache the lookup. See WP_Customize_Custom_CSS_Setting::update().
+			 * Cache the lookup. See wp_update_custom_css_post().
 			 * @todo This should get cleared if a custom_css post is added/removed.
 			 */
-			if ( $post ) {
-				set_theme_mod( 'custom_css_post_id', $post->ID );
-			} elseif ( -1 !== $post_id ) {
-				set_theme_mod( 'custom_css_post_id', -1 );
-			}
+			set_theme_mod( 'custom_css_post_id', $post ? $post->ID : -1 );
 		}
 	} else {
 		$query = new WP_Query( $custom_css_query_vars );
@@ -1788,9 +1787,15 @@ function wp_update_custom_css_post( $css, $args = array() ) {
 	} else {
 		$r = wp_insert_post( wp_slash( $post_data ), true );
 
-		// Trigger creation of a revision. This should be removed once #30854 is resolved.
-		if ( ! is_wp_error( $r ) && 0 === count( wp_get_post_revisions( $r ) ) ) {
-			wp_save_post_revision( $r );
+		if ( ! is_wp_error( $r ) ) {
+			if ( get_stylesheet() === $args['stylesheet'] ) {
+				set_theme_mod( 'custom_css_post_id', $r );
+			}
+
+			// Trigger creation of a revision. This should be removed once #30854 is resolved.
+			if ( 0 === count( wp_get_post_revisions( $r ) ) ) {
+				wp_save_post_revision( $r );
+			}
 		}
 	}
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index b75c62e7a3..6c173d08f2 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-39687';
+$wp_version = '4.8-alpha-39688';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.