From b55ca667595b2fceec604f04bace814971b0e4fe Mon Sep 17 00:00:00 2001
From: Peter Wilson <wilson@peterwilson.cc>
Date: Mon, 2 Sep 2019 02:27:55 +0000
Subject: [PATCH] #43590: Use robots meta tag to better discourage search
 engines.

This changes the "discourage search engines" option to output a `noindex, nofollow` robots meta tag. `Disallow: /` is removed from the `robots.txt` to allow search engines to discover they are requested not to index the site.

Disallowing search engines from accessing a site in the `robots.txt` file can result in search engines listing a site with a fragment (a listing without content).

Props donmhico, jonoaldersonwp.
Fixes #43590.


Built from https://develop.svn.wordpress.org/trunk@45928


git-svn-id: http://core.svn.wordpress.org/trunk@45739 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/functions.php        | 15 +++++++--------
 wp-includes/general-template.php | 10 ++++++++--
 wp-includes/version.php          |  2 +-
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index bece4e7914..951020d387 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -1582,6 +1582,8 @@ function do_feed_atom( $for_comments ) {
  * Displays the default robots.txt file content.
  *
  * @since 2.1.0
+ * @since 5.3.0 Remove the "Disallow: /" output if search engine visiblity is
+ *              discouraged in favor of robots meta HTML tag in wp_no_robots().
  */
 function do_robots() {
 	header( 'Content-Type: text/plain; charset=utf-8' );
@@ -1595,14 +1597,11 @@ function do_robots() {
 
 	$output = "User-agent: *\n";
 	$public = get_option( 'blog_public' );
-	if ( '0' == $public ) {
-		$output .= "Disallow: /\n";
-	} else {
-		$site_url = parse_url( site_url() );
-		$path     = ( ! empty( $site_url['path'] ) ) ? $site_url['path'] : '';
-		$output  .= "Disallow: $path/wp-admin/\n";
-		$output  .= "Allow: $path/wp-admin/admin-ajax.php\n";
-	}
+
+	$site_url = parse_url( site_url() );
+	$path     = ( ! empty( $site_url['path'] ) ) ? $site_url['path'] : '';
+	$output  .= "Disallow: $path/wp-admin/\n";
+	$output  .= "Allow: $path/wp-admin/admin-ajax.php\n";
 
 	/**
 	 * Filters the robots.txt output.
diff --git a/wp-includes/general-template.php b/wp-includes/general-template.php
index d6bcc019b1..614853860f 100644
--- a/wp-includes/general-template.php
+++ b/wp-includes/general-template.php
@@ -2986,12 +2986,18 @@ function noindex() {
  * Display a noindex meta tag.
  *
  * Outputs a noindex meta tag that tells web robots not to index the page content.
- * Typical usage is as a wp_head callback. add_action( 'wp_head', 'wp_no_robots' );
+ * Typical usage is as a {@see 'wp_head'} callback. add_action( 'wp_head', 'wp_no_robots' );
  *
  * @since 3.3.0
+ * @since 5.3.0 Echo "noindex,nofollow" if search engine visibility is discouraged.
  */
 function wp_no_robots() {
-	echo "<meta name='robots' content='noindex,follow' />\n";
+	if ( get_option( 'blog_public' ) ) {
+		echo "<meta name='robots' content='noindex,follow' />\n";
+		return;
+	}
+
+	echo "<meta name='robots' content='noindex,nofollow' />\n";
 }
 
 /**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 8b6f0ac276..575b3f8220 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-45927';
+$wp_version = '5.3-alpha-45928';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.