Introduce WP_REDIS_DISABLE_GROUP_FLUSH to disable group flushing (#532)

Author: yatsukhnenko

README.md

@@ -61,6 +61,7 @@ The Redis Object Cache plugin comes with vast set of configuration options. If y
 | `WP_REDIS_DISABLE_BANNERS`           | `false`     | Disables promotional banners |
 | `WP_REDIS_DISABLE_DROPIN_CHECK`      | `false`     | Disables the extended drop-in write test |
 | `WP_REDIS_DISABLE_DROPIN_AUTOUPDATE` | `false`     | Disables the drop-in auto-update |
+| `WP_REDIS_DISABLE_GROUP_FLUSH`       | `false`     | Disables group flushing with Lua script and uses `flushdb` call instead |
 | `WP_REDIS_SSL_CONTEXT`               | `[]`        | TLS connection options for `tls` or `rediss` scheme |
 
 </details>

includes/object-cache.php

@@ -1768,6 +1768,10 @@ public function flush() {
 	 * @return bool Returns TRUE on success or FALSE on failure.
 	 */
     public function flush_group( $group ) {
+        if ( defined( 'WP_REDIS_DISABLE_GROUP_FLUSH' ) && WP_REDIS_DISABLE_GROUP_FLUSH ) {
+            return $this->flush();
+        }
+
         $san_group = $this->sanitize_key_part( $group );
 
         if ( is_multisite() && ! $this->is_global_group( $san_group ) ) {