Search Engine Discouraged shown on dashboard when upgrading from an earlier version than 2.1

[bswatson]

When upgrading a site to a version newer than 3.7 when the original version of WordPress was before 2.1, it's possible for the "Search Engines Discouraged" text to be shown on the dashboard, even if the setting isn't configured.

In the dashboard code, the conditional to check for this option checks specifically if get_option( 'blog_public' ) is set to '1'.

<?php
if ( ! is_network_admin() && ! is_user_admin() && current_user_can( 'manage_options' ) && '1' != get_option( 'blog_public' ) ) {

Ref: https://core.trac.wordpress.org/browser/trunk/src/wp-admin/includes/dashboard.php#L296

The option settings, split logic on has_action( 'blog_privacy_selector' ). If the selector exists, it shows a radio button that set the option as '1' if search engines are allowed to index and '0' if they are not. If the option is not selected, search engines are not allowed.

The previous behavior was a checkbox that would set the option to 0 only if search engines were discouraged, and deselecting the checkbox would enable search engines.

<?php if ( has_action( 'blog_privacy_selector' ) ) : ?>
        <input id="blog-public" type="radio" name="blog_public" value="1" <?php checked('1', get_option('blog_public')); ?> />
        <label for="blog-public"><?php _e( 'Allow search engines to index this site' );?></label><br/>
        <input id="blog-norobots" type="radio" name="blog_public" value="0" <?php checked('0', get_option('blog_public')); ?> />
        <label for="blog-norobots"><?php _e( 'Discourage search engines from indexing this site' ); ?></label>
        <p class="description"><?php _e( 'Note: Neither of these options blocks access to your site &mdash; it is up to search engines to honor your request.' ); ?></p>
        <?php
        /**
         * Enable the legacy 'Site Visibility' privacy options.
         *
         * By default the privacy options form displays a single checkbox to 'discourage' search
         * engines from indexing the site. Hooking to this action serves a dual purpose:
         * 1. Disable the single checkbox in favor of a multiple-choice list of radio buttons.
         * 2. Open the door to adding additional radio button choices to the list.
         *
         * Hooking to this action also converts the 'Search Engine Visibility' heading to the more
         * open-ended 'Site Visibility' heading.
         *
         * @since 2.1.0
         */
        do_action( 'blog_privacy_selector' );
        ?>
<?php else : ?>
        <label for="blog_public"><input name="blog_public" type="checkbox" id="blog_public" value="0" <?php checked( '0', get_option( 'blog_public' ) ); ?> />
        <?php _e( 'Discourage search engines from indexing this site' ); ?></label>
        <p class="description"><?php _e( 'It is up to search engines to honor this request.' ); ?></p>
<?php endif; ?>

Ref: ​https://github.com/WordPress/WordPress/blob/master/wp-admin/options-reading.php#L113

On upgrade, the default value allowed search engines to be index, but now displays that they should not.

This only appears to be display issue on the dashboard, as output of the no-index meta checks against 0 instead of 1.

<?php 
function noindex() {
        // If the blog is not public, tell robots to go away.
        if ( '0' == get_option('blog_public') )
                wp_no_robots();
}

Ref: ​https://github.com/WordPress/WordPress/blob/master/wp-includes/general-template.php#L2608

[swissspidy]

The default value of that option indeed changed over the years. The bug mentioned here was introduced in [26700] for 3.8.

It seems like a '0' === get_option( 'blog_public' ) check in wp-admin/includes/dashboard.php (instead of checking against '1') should really be enough to fix this.

[swissspidy]

34860.diff​ uses the same check against '0' as in noindex(), preventing from incorrectly showing "Search Engines Discouraged" text when the blog_public option is not set.

[swissspidy]

In 35873:

Dashboard: Do not show "Search Engines Discouraged" text when the blog_public option is not set.

Search engines are only discouraged from indexing the site when the option is explicitly set to 0.

Fixes #34860.