From 0b8740d868559065812b6b7201d44ed9affdaae9 Mon Sep 17 00:00:00 2001
From: Peter Wilson <wilson@peterwilson.cc>
Date: Tue, 22 Nov 2016 11:41:34 +0000
Subject: [PATCH] Themes: Prevent unneeded database updates in
 `wp_get_custom_css_post()`.

When a custom header image was set but custom CSS was not, `wp_get_custom_css_post()` was generating an UPDATE query on every frontend request.

In theme options the header image meta data is stored as an object. In `update_option()` this hits an edge case as the resource IDs of the old and new values never match.

This changes the logic of `wp_get_custom_css_post()` to ensure `set_theme_mod()` is only called when the custom CSS has changed.

Props bradyvercher, helen.
Fixes #38866.

Built from https://develop.svn.wordpress.org/trunk@39338


git-svn-id: http://core.svn.wordpress.org/trunk@39278 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/theme.php   | 15 ++++++++++-----
 wp-includes/version.php |  2 +-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index 13bf9ca1a1..eea50a50dc 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -1639,7 +1639,7 @@ function wp_get_custom_css_post( $stylesheet = '' ) {
 		'post_type'              => 'custom_css',
 		'post_status'            => get_post_stati(),
 		'name'                   => sanitize_title( $stylesheet ),
-		'number'                 => 1,
+		'posts_per_page'         => 1,
 		'no_found_rows'          => true,
 		'cache_results'          => true,
 		'update_post_meta_cache' => false,
@@ -1649,16 +1649,21 @@ function wp_get_custom_css_post( $stylesheet = '' ) {
 	$post = null;
 	if ( get_stylesheet() === $stylesheet ) {
 		$post_id = get_theme_mod( 'custom_css_post_id' );
-		if ( ! $post_id || ! get_post( $post_id ) ) {
+
+		if ( $post_id > 0 && get_post( $post_id ) ) {
+			$post = get_post( $post_id );
+		} else {
 			$query = new WP_Query( $custom_css_query_vars );
 			$post = $query->post;
 			/*
 			 * Cache the lookup. See WP_Customize_Custom_CSS_Setting::update().
 			 * @todo This should get cleared if a custom_css post is added/removed.
 			 */
-			set_theme_mod( 'custom_css_post_id', $post ? $post->ID : -1 );
-		} elseif ( $post_id > 0 ) {
-			$post = get_post( $post_id );
+			if ( $post ) {
+				set_theme_mod( 'custom_css_post_id', $post->ID );
+			} elseif ( -1 !== $post_id ) {
+				set_theme_mod( 'custom_css_post_id', -1 );
+			}
 		}
 	} else {
 		$query = new WP_Query( $custom_css_query_vars );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 19abed8869..3be541c1d3 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-beta4-39337';
+$wp_version = '4.7-beta4-39338';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.