Fix table prefix in multisite

CHANGELOG.md

@@ -2,6 +2,16 @@
 
 This library adheres to [Semantic Versioning](https://semver.org/) and [Keep a CHANGELOG](https://keepachangelog.com/en/1.0.0/).
 
+## 0.3.0
+
+## Changed
+
+- When storing items with the PSR-16 adapter, the group name is now automatically prefixed to avoid unintended data loss when flushing the cache.
+
+### Fixed
+
+- Incorrect database table prefix in multisite installations.
+
 ## 0.2.0
 
 ### Added

README.md

@@ -53,6 +53,18 @@ $cache->clear();
 
 Note that the cache adapter will store data in a custom array structure, as described [in the wp-psr16 README](https://github.com/alleyinteractive/wp-psr16/blob/5ff411661f9682b3184dab596180a7a3edcaf446/README.md#implementation-details).
 
+## Why Not Use Options?
+
+There's nothing wrong with using options for storing key-value data, but it comes with overhead, including:
+
+- Managing autoloading and the `alloptions` cache.
+- `pre_option_` and `option_` filters on the values.
+- Settings registration and default values.
+
+Big Pit doesn't have autoloading, filters, or registered keys, so it might work for you if you don't need these features.
+
+Or, you might plan to store thousands of rows, and you don't want to dilute the options table with that amount of data.
+
 ## About
 
 ### License

src/class-big-pit.php

@@ -50,7 +50,7 @@ public static function instance(): self {
 	public function boot(): void {
 		global $wpdb;
 
-		$wpdb->big_pit = $wpdb->base_prefix . 'big_pit';
+		$wpdb->big_pit = $wpdb->get_blog_prefix() . 'big_pit';
 
 		if ( defined( 'WP_INSTALLING' ) ) {
 			return;
@@ -195,7 +195,7 @@ public function flush_group( string $group ): void {
 	private function upsert(): void {
 		global $wpdb;
 
-		$available_version = '1';
+		$available_version = '2';
 		$installed_version = get_option( 'wp_big_pit_database_version', '0' );
 
 		if ( $available_version === $installed_version ) {
@@ -206,9 +206,15 @@ private function upsert(): void {
 			require_once ABSPATH . '/wp-admin/includes/upgrade.php';
 		}
 
-		if ( ! $installed_version ) {
-			$delta = \dbDelta(
-				<<<SQL
+		// Ensure the database version is at least version 2.
+		if ( ! $installed_version || '1' === $installed_version ) {
+			/*
+			 * Create the table if this is a new installation or if this is a site in
+			 * a multisite that didn't get a site-specific table at version 1.
+			 */
+			if ( ! $installed_version || $wpdb->blogid > 1 ) {
+				$delta = \dbDelta(
+					<<<SQL
 CREATE TABLE {$wpdb->big_pit} (
 	item_id bigint(20) UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
 	item_group varchar(255) NOT NULL,
@@ -218,13 +224,14 @@ private function upsert(): void {
 	KEY key_value (item_key(191), item_value(100))
 ) {$wpdb->get_charset_collate()};
 SQL
-			);
+				);
 
-			if ( ! isset( $delta[ $wpdb->big_pit ] ) ) {
-				throw new \Exception( 'Failed to create table.' );
+				if ( ! isset( $delta[ $wpdb->big_pit ] ) ) {
+					throw new \Exception( 'Failed to create table.' );
+				}
 			}
 
-			$installed_version = '1';
+			$installed_version = '2';
 		}
 
 		update_option( 'wp_big_pit_database_version', $installed_version );

src/simplecache/class-big-pit-adapter.php

@@ -41,7 +41,8 @@ public static function create( string $group ): CacheInterface {
 					limit: 172,
 					origin: new self(
 						pit: Big_Pit::instance(),
-						group: $group,
+						// Prefix the group so that `flush()` doesn't wipe out other data.
+						group: "_psr16_{$group}",
 					),
 				),
 			),