From 7d87ce12c8406d177e086f83dfa8a26069cd61ca Mon Sep 17 00:00:00 2001
From: desrosj <desrosj@git.wordpress.org>
Date: Tue, 20 Sep 2022 02:51:09 +0000
Subject: [PATCH] Networks and Sites: Officially remove global terms.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Global terms was a feature from the WordPress MU days where multisite and single site installs used different code bases.

In WordPress 3.0, WordPress MU was merged into one location and the UI [14854] and “on” switch [14880] for global terms were completely removed.

Even before this merge, global terms was bug infested and unreliable. After [14854]/[14880], the feature was no longer maintained and became increasingly broken as taxonomies progressed without it (term splitting and term meta do not work at all). At this point, the feature has not worked in 12+ years and there’s no hope for saving it.

This deprecates the remaining global terms related code and no-ops the functions.

Global terms, you don’t have to go home, but you can’t stay here.

Props scribu, wonderboymusic, SergeyBiryukov, nacin, pento, desrosj, johnjamesjacoby, johnbillion, dd32.
Fixes #21734.
Built from https://develop.svn.wordpress.org/trunk@54240


git-svn-id: http://core.svn.wordpress.org/trunk@53799 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/edit-tag-form.php                    |  2 -
 wp-admin/edit-tags.php                        |  6 +-
 .../includes/class-wp-terms-list-table.php    | 10 +-
 wp-admin/includes/ms-admin-filters.php        |  3 -
 wp-admin/includes/ms-deprecated.php           | 30 ++++++
 wp-admin/includes/ms.php                      | 23 -----
 wp-admin/includes/schema.php                  |  1 -
 wp-admin/includes/upgrade.php                 | 46 +---------
 wp-admin/network/settings.php                 |  1 -
 wp-includes/class-wpdb.php                    | 16 +++-
 wp-includes/functions.php                     | 35 -------
 wp-includes/ms-default-filters.php            |  1 -
 wp-includes/ms-deprecated.php                 | 31 +++++++
 wp-includes/ms-functions.php                  | 91 -------------------
 wp-includes/version.php                       |  2 +-
 15 files changed, 83 insertions(+), 215 deletions(-)

diff --git a/wp-admin/edit-tag-form.php b/wp-admin/edit-tag-form.php
index 9b2110398c..494c15547b 100644
--- a/wp-admin/edit-tag-form.php
+++ b/wp-admin/edit-tag-form.php
@@ -148,7 +148,6 @@ if ( isset( $tag->name ) ) {
 			<td><input name="name" id="name" type="text" value="<?php echo $tag_name_value; ?>" size="40" aria-required="true" aria-describedby="name-description" />
 			<p class="description" id="name-description"><?php echo $tax->labels->name_field_description; ?></p></td>
 		</tr>
-<?php if ( ! global_terms_enabled() ) { ?>
 		<tr class="form-field term-slug-wrap">
 			<th scope="row"><label for="slug"><?php _e( 'Slug' ); ?></label></th>
 			<?php
@@ -170,7 +169,6 @@ if ( isset( $tag->name ) ) {
 			<td><input name="slug" id="slug" type="text" value="<?php echo esc_attr( $slug ); ?>" size="40" aria-describedby="slug-description" />
 			<p class="description" id="slug-description"><?php echo $tax->labels->slug_field_description; ?></p></td>
 		</tr>
-<?php } ?>
 <?php if ( is_taxonomy_hierarchical( $taxonomy ) ) : ?>
 		<tr class="form-field term-parent-wrap">
 			<th scope="row"><label for="parent"><?php echo esc_html( $tax->labels->parent_item ); ?></label></th>
diff --git a/wp-admin/edit-tags.php b/wp-admin/edit-tags.php
index abbc330b82..9812d97c76 100644
--- a/wp-admin/edit-tags.php
+++ b/wp-admin/edit-tags.php
@@ -280,9 +280,7 @@ if ( 'category' === $taxonomy || 'link_category' === $taxonomy || 'post_tag' ===
 		$help .= '<ul>' .
 		'<li>' . __( '<strong>Name</strong> &mdash; The name is how it appears on your site.' ) . '</li>';
 
-		if ( ! global_terms_enabled() ) {
-			$help .= '<li>' . __( '<strong>Slug</strong> &mdash; The &#8220;slug&#8221; is the URL-friendly version of the name. It is usually all lowercase and contains only letters, numbers, and hyphens.' ) . '</li>';
-		}
+		$help .= '<li>' . __( '<strong>Slug</strong> &mdash; The &#8220;slug&#8221; is the URL-friendly version of the name. It is usually all lowercase and contains only letters, numbers, and hyphens.' ) . '</li>';
 
 		if ( 'category' === $taxonomy ) {
 			$help .= '<li>' . __( '<strong>Parent</strong> &mdash; Categories, unlike tags, can have a hierarchy. You might have a Jazz category, and under that have child categories for Bebop and Big Band. Totally optional. To create a subcategory, just choose another category from the Parent dropdown.' ) . '</li>';
@@ -456,13 +454,11 @@ if ( $can_edit_terms ) {
 	<input name="tag-name" id="tag-name" type="text" value="" size="40" aria-required="true" aria-describedby="name-description" />
 	<p id="name-description"><?php echo $tax->labels->name_field_description; ?></p>
 </div>
-	<?php if ( ! global_terms_enabled() ) : ?>
 <div class="form-field term-slug-wrap">
 	<label for="tag-slug"><?php _e( 'Slug' ); ?></label>
 	<input name="slug" id="tag-slug" type="text" value="" size="40" aria-describedby="slug-description" />
 	<p id="slug-description"><?php echo $tax->labels->slug_field_description; ?></p>
 </div>
-<?php endif; // global_terms_enabled() ?>
 	<?php if ( is_taxonomy_hierarchical( $taxonomy ) ) : ?>
 <div class="form-field term-parent-wrap">
 	<label for="parent"><?php echo esc_html( $tax->labels->parent_item ); ?></label>
diff --git a/wp-admin/includes/class-wp-terms-list-table.php b/wp-admin/includes/class-wp-terms-list-table.php
index bae5a11b1f..c43ec62689 100644
--- a/wp-admin/includes/class-wp-terms-list-table.php
+++ b/wp-admin/includes/class-wp-terms-list-table.php
@@ -665,12 +665,10 @@ class WP_Terms_List_Table extends WP_List_Table {
 					<span class="input-text-wrap"><input type="text" name="name" class="ptitle" value="" /></span>
 				</label>
 
-				<?php if ( ! global_terms_enabled() ) : ?>
-					<label>
-						<span class="title"><?php _e( 'Slug' ); ?></span>
-						<span class="input-text-wrap"><input type="text" name="slug" class="ptitle" value="" /></span>
-					</label>
-				<?php endif; ?>
+				<label>
+					<span class="title"><?php _e( 'Slug' ); ?></span>
+					<span class="input-text-wrap"><input type="text" name="slug" class="ptitle" value="" /></span>
+				</label>
 				</div>
 			</fieldset>
 
diff --git a/wp-admin/includes/ms-admin-filters.php b/wp-admin/includes/ms-admin-filters.php
index 9e5fcaf2a9..b1d73825f1 100644
--- a/wp-admin/includes/ms-admin-filters.php
+++ b/wp-admin/includes/ms-admin-filters.php
@@ -22,9 +22,6 @@ add_action( 'wpmueditblogaction', 'upload_space_setting' );
 // Network hooks.
 add_action( 'update_site_option_admin_email', 'wp_network_admin_email_change_notification', 10, 4 );
 
-// Taxonomy hooks.
-add_filter( 'get_term', 'sync_category_tag_slugs', 10, 2 );
-
 // Post hooks.
 add_filter( 'wp_insert_post_data', 'avoid_blog_page_permalink_collision', 10, 2 );
 
diff --git a/wp-admin/includes/ms-deprecated.php b/wp-admin/includes/ms-deprecated.php
index fb45676a4e..519159b61b 100644
--- a/wp-admin/includes/ms-deprecated.php
+++ b/wp-admin/includes/ms-deprecated.php
@@ -108,3 +108,33 @@ function wpmu_get_blog_allowedthemes( $blog_id = 0 ) {
  * @deprecated 3.5.0
  */
 function ms_deprecated_blogs_file() {}
+
+if ( ! function_exists( 'install_global_terms' ) ) :
+	/**
+	 * Install global terms.
+	 *
+	 * @since 3.0.0
+	 * @since 6.1.0 This function no longer does anything.
+	 * @deprecated 6.1.0
+	 */
+	function install_global_terms() {
+		_deprecated_function( __FUNCTION__, '6.1.0' );
+	}
+endif;
+
+/**
+ * Synchronizes category and post tag slugs when global terms are enabled.
+ *
+ * @since 3.0.0
+ * @since 6.1.0 This function no longer does anything.
+ * @deprecated 6.1.0
+ *
+ * @param WP_Term|array $term     The term.
+ * @param string        $taxonomy The taxonomy for `$term`.
+ * @return WP_Term|array Always returns `$term`.
+ */
+function sync_category_tag_slugs( $term, $taxonomy ) {
+	_deprecated_function( __FUNCTION__, '6.1.0' );
+
+	return $term;
+}
diff --git a/wp-admin/includes/ms.php b/wp-admin/includes/ms.php
index af5bd1abd4..741d02e9c9 100644
--- a/wp-admin/includes/ms.php
+++ b/wp-admin/includes/ms.php
@@ -543,29 +543,6 @@ function format_code_lang( $code = '' ) {
 	return strtr( $code, $lang_codes );
 }
 
-/**
- * Synchronizes category and post tag slugs when global terms are enabled.
- *
- * @since 3.0.0
- *
- * @param WP_Term|array $term     The term.
- * @param string        $taxonomy The taxonomy for `$term`. Should be 'category' or 'post_tag', as these are
- *                                the only taxonomies which are processed by this function; anything else
- *                                will be returned untouched.
- * @return WP_Term|array Returns `$term`, after filtering the 'slug' field with `sanitize_title()`
- *                       if `$taxonomy` is 'category' or 'post_tag'.
- */
-function sync_category_tag_slugs( $term, $taxonomy ) {
-	if ( global_terms_enabled() && ( 'category' === $taxonomy || 'post_tag' === $taxonomy ) ) {
-		if ( is_object( $term ) ) {
-			$term->slug = sanitize_title( $term->name );
-		} else {
-			$term['slug'] = sanitize_title( $term['name'] );
-		}
-	}
-	return $term;
-}
-
 /**
  * Displays an access denied message when a user tries to view a site's dashboard they
  * do not have access to.
diff --git a/wp-admin/includes/schema.php b/wp-admin/includes/schema.php
index 504acbf949..c8bc92e44c 100644
--- a/wp-admin/includes/schema.php
+++ b/wp-admin/includes/schema.php
@@ -1270,7 +1270,6 @@ We hope you enjoy your new site. Thanks!
 		'add_new_users'               => '0',
 		'upload_space_check_disabled' => is_multisite() ? get_site_option( 'upload_space_check_disabled' ) : '1',
 		'subdomain_install'           => $subdomain_install,
-		'global_terms_enabled'        => global_terms_enabled() ? '1' : '0',
 		'ms_files_rewriting'          => is_multisite() ? get_site_option( 'ms_files_rewriting' ) : '0',
 		'user_count'                  => get_site_option( 'user_count' ),
 		'initial_db_version'          => get_option( 'initial_db_version' ),
diff --git a/wp-admin/includes/upgrade.php b/wp-admin/includes/upgrade.php
index 5030483769..802269e047 100644
--- a/wp-admin/includes/upgrade.php
+++ b/wp-admin/includes/upgrade.php
@@ -159,24 +159,7 @@ if ( ! function_exists( 'wp_install_defaults' ) ) :
 		/* translators: Default category slug. */
 		$cat_slug = sanitize_title( _x( 'Uncategorized', 'Default category slug' ) );
 
-		if ( global_terms_enabled() ) {
-			$cat_id = $wpdb->get_var( $wpdb->prepare( "SELECT cat_ID FROM {$wpdb->sitecategories} WHERE category_nicename = %s", $cat_slug ) );
-			if ( null == $cat_id ) {
-				$wpdb->insert(
-					$wpdb->sitecategories,
-					array(
-						'cat_ID'            => 0,
-						'cat_name'          => $cat_name,
-						'category_nicename' => $cat_slug,
-						'last_updated'      => current_time( 'mysql', true ),
-					)
-				);
-				$cat_id = $wpdb->insert_id;
-			}
-			update_option( 'default_category', $cat_id );
-		} else {
-			$cat_id = 1;
-		}
+		$cat_id = 1;
 
 		$wpdb->insert(
 			$wpdb->terms,
@@ -3537,33 +3520,6 @@ function pre_schema_upgrade() {
 	}
 }
 
-if ( ! function_exists( 'install_global_terms' ) ) :
-	/**
-	 * Install global terms.
-	 *
-	 * @since 3.0.0
-	 *
-	 * @global wpdb   $wpdb            WordPress database abstraction object.
-	 * @global string $charset_collate
-	 */
-	function install_global_terms() {
-		global $wpdb, $charset_collate;
-		$ms_queries = "
-CREATE TABLE $wpdb->sitecategories (
-  cat_ID bigint(20) NOT NULL auto_increment,
-  cat_name varchar(55) NOT NULL default '',
-  category_nicename varchar(200) NOT NULL default '',
-  last_updated timestamp NOT NULL,
-  PRIMARY KEY  (cat_ID),
-  KEY category_nicename (category_nicename),
-  KEY last_updated (last_updated)
-) $charset_collate;
-";
-		// Now create tables.
-		dbDelta( $ms_queries );
-	}
-endif;
-
 /**
  * Determine if global tables should be upgraded.
  *
diff --git a/wp-admin/network/settings.php b/wp-admin/network/settings.php
index 75c13ae863..d162be751b 100644
--- a/wp-admin/network/settings.php
+++ b/wp-admin/network/settings.php
@@ -100,7 +100,6 @@ if ( $_POST ) {
 		'welcome_email',
 		'welcome_user_email',
 		'fileupload_maxk',
-		'global_terms_enabled',
 		'illegal_names',
 		'limited_email_domains',
 		'banned_email_domains',
diff --git a/wp-includes/class-wpdb.php b/wp-includes/class-wpdb.php
index e81b9caf79..043bca0a07 100644
--- a/wp-includes/class-wpdb.php
+++ b/wp-includes/class-wpdb.php
@@ -340,10 +340,19 @@ class wpdb {
 		'signups',
 		'site',
 		'sitemeta',
-		'sitecategories',
 		'registration_log',
 	);
 
+	/**
+	 * List of deprecated WordPress Multisite global tables.
+	 *
+	 * @since 6.1.0
+	 *
+	 * @see wpdb::tables()
+	 * @var string[]
+	 */
+	public $old_ms_global_tables = array( 'sitecategories' );
+
 	/**
 	 * WordPress Comments table.
 	 *
@@ -1123,11 +1132,13 @@ class wpdb {
 	 * - 'old' - returns tables which are deprecated.
 	 *
 	 * @since 3.0.0
+	 * @since 6.1.0 `old` now includes deprecated multisite global tables only on multisite.
 	 *
 	 * @uses wpdb::$tables
 	 * @uses wpdb::$old_tables
 	 * @uses wpdb::$global_tables
 	 * @uses wpdb::$ms_global_tables
+	 * @uses wpdb::$old_ms_global_tables
 	 *
 	 * @param string $scope   Optional. Possible values include 'all', 'global', 'ms_global', 'blog',
 	 *                        or 'old' tables. Default 'all'.
@@ -1159,6 +1170,9 @@ class wpdb {
 				break;
 			case 'old':
 				$tables = $this->old_tables;
+				if ( is_multisite() ) {
+					$tables = array_merge( $tables, $this->old_ms_global_tables );
+				}
 				break;
 			default:
 				return array();
diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 5d32afa578..f78b0cc6ff 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -6219,41 +6219,6 @@ function get_main_network_id() {
 	return (int) apply_filters( 'get_main_network_id', $main_network_id );
 }
 
-/**
- * Determines whether global terms are enabled.
- *
- * @since 3.0.0
- *
- * @return bool True if multisite and global terms enabled.
- */
-function global_terms_enabled() {
-	if ( ! is_multisite() ) {
-		return false;
-	}
-
-	static $global_terms = null;
-	if ( is_null( $global_terms ) ) {
-
-		/**
-		 * Filters whether global terms are enabled.
-		 *
-		 * Returning a non-null value from the filter will effectively short-circuit the function
-		 * and return the value of the 'global_terms_enabled' site option instead.
-		 *
-		 * @since 3.0.0
-		 *
-		 * @param null $enabled Whether global terms are enabled.
-		 */
-		$filter = apply_filters( 'global_terms_enabled', null );
-		if ( ! is_null( $filter ) ) {
-			$global_terms = (bool) $filter;
-		} else {
-			$global_terms = (bool) get_site_option( 'global_terms_enabled', false );
-		}
-	}
-	return $global_terms;
-}
-
 /**
  * Determines whether site meta is enabled.
  *
diff --git a/wp-includes/ms-default-filters.php b/wp-includes/ms-default-filters.php
index 3411e7dba0..c0af7215ff 100644
--- a/wp-includes/ms-default-filters.php
+++ b/wp-includes/ms-default-filters.php
@@ -75,7 +75,6 @@ add_action( 'template_redirect', 'maybe_redirect_404' );
 add_filter( 'allowed_redirect_hosts', 'redirect_this_site' );
 
 // Administration.
-add_filter( 'term_id_filter', 'global_terms', 10, 2 );
 add_action( 'after_delete_post', '_update_posts_count_on_delete' );
 add_action( 'delete_post', '_update_blog_date_on_post_delete' );
 add_action( 'transition_post_status', '_update_blog_date_on_post_publish', 10, 3 );
diff --git a/wp-includes/ms-deprecated.php b/wp-includes/ms-deprecated.php
index 6ce7af2be8..224dc1586d 100644
--- a/wp-includes/ms-deprecated.php
+++ b/wp-includes/ms-deprecated.php
@@ -730,3 +730,34 @@ function update_user_status( $id, $pref, $value, $deprecated = null ) {
 
 	return $value;
 }
+/**
+ * Determines whether global terms are enabled.
+ *
+ * @since 3.0.0
+ * @since 6.1.0 This function now always returns false.
+ * @deprecated 6.1.0
+ *
+ * @return bool Always returns false.
+ */
+function global_terms_enabled() {
+	_deprecated_function( __FUNCTION__, '6.1.0' );
+
+	return false;
+}
+
+/**
+ * Maintains a canonical list of terms by syncing terms created for each blog with the global terms table.
+ *
+ * @since 3.0.0
+ * @since 6.1.0 This function no longer does anything.
+ * @deprecated 6.1.0
+ *
+ * @param int    $term_id    An ID for a term on the current blog.
+ * @param string $deprecated Not used.
+ * @return int An ID from the global terms table mapped from $term_id.
+ */
+function global_terms( $term_id, $deprecated = '' ) {
+	_deprecated_function( __FUNCTION__, '6.1.0' );
+
+	return $term_id;
+}
diff --git a/wp-includes/ms-functions.php b/wp-includes/ms-functions.php
index 2bb9c276dd..b48848b45e 100644
--- a/wp-includes/ms-functions.php
+++ b/wp-includes/ms-functions.php
@@ -2049,97 +2049,6 @@ function wpmu_log_new_registrations( $blog_id, $user_id ) {
 	}
 }
 
-/**
- * Maintains a canonical list of terms by syncing terms created for each blog with the global terms table.
- *
- * @since 3.0.0
- *
- * @see term_id_filter
- *
- * @global wpdb $wpdb WordPress database abstraction object.
- *
- * @param int    $term_id    An ID for a term on the current blog.
- * @param string $deprecated Not used.
- * @return int An ID from the global terms table mapped from $term_id.
- */
-function global_terms( $term_id, $deprecated = '' ) {
-	global $wpdb;
-	static $global_terms_recurse = null;
-
-	if ( ! global_terms_enabled() ) {
-		return $term_id;
-	}
-
-	// Prevent a race condition.
-	$recurse_start = false;
-	if ( null === $global_terms_recurse ) {
-		$recurse_start        = true;
-		$global_terms_recurse = 1;
-	} elseif ( 10 < $global_terms_recurse++ ) {
-		return $term_id;
-	}
-
-	$term_id = (int) $term_id;
-	$c       = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->terms WHERE term_id = %d", $term_id ) );
-
-	$global_id = $wpdb->get_var( $wpdb->prepare( "SELECT cat_ID FROM $wpdb->sitecategories WHERE category_nicename = %s", $c->slug ) );
-	if ( null == $global_id ) {
-		$used_global_id = $wpdb->get_var( $wpdb->prepare( "SELECT cat_ID FROM $wpdb->sitecategories WHERE cat_ID = %d", $c->term_id ) );
-		if ( null == $used_global_id ) {
-			$wpdb->insert(
-				$wpdb->sitecategories,
-				array(
-					'cat_ID'            => $term_id,
-					'cat_name'          => $c->name,
-					'category_nicename' => $c->slug,
-				)
-			);
-			$global_id = $wpdb->insert_id;
-			if ( empty( $global_id ) ) {
-				return $term_id;
-			}
-		} else {
-			$max_global_id = $wpdb->get_var( "SELECT MAX(cat_ID) FROM $wpdb->sitecategories" );
-			$max_local_id  = $wpdb->get_var( "SELECT MAX(term_id) FROM $wpdb->terms" );
-			$new_global_id = max( $max_global_id, $max_local_id ) + mt_rand( 100, 400 );
-			$wpdb->insert(
-				$wpdb->sitecategories,
-				array(
-					'cat_ID'            => $new_global_id,
-					'cat_name'          => $c->name,
-					'category_nicename' => $c->slug,
-				)
-			);
-			$global_id = $wpdb->insert_id;
-		}
-	} elseif ( $global_id != $term_id ) {
-		$local_id = $wpdb->get_var( $wpdb->prepare( "SELECT term_id FROM $wpdb->terms WHERE term_id = %d", $global_id ) );
-		if ( null != $local_id ) {
-			global_terms( $local_id );
-			if ( 10 < $global_terms_recurse ) {
-				$global_id = $term_id;
-			}
-		}
-	}
-
-	if ( $global_id != $term_id ) {
-		if ( get_option( 'default_category' ) == $term_id ) {
-			update_option( 'default_category', $global_id );
-		}
-
-		$wpdb->update( $wpdb->terms, array( 'term_id' => $global_id ), array( 'term_id' => $term_id ) );
-		$wpdb->update( $wpdb->term_taxonomy, array( 'term_id' => $global_id ), array( 'term_id' => $term_id ) );
-		$wpdb->update( $wpdb->term_taxonomy, array( 'parent' => $global_id ), array( 'parent' => $term_id ) );
-
-		clean_term_cache( $term_id );
-	}
-	if ( $recurse_start ) {
-		$global_terms_recurse = null;
-	}
-
-	return $global_id;
-}
-
 /**
  * Ensures that the current site's domain is listed in the allowed redirect host list.
  *
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 83ba3f1159..ddfac1876b 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-54239';
+$wp_version = '6.1-alpha-54240';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.