[8.x] Improve PhpRedis flushing (#40544)

* move cluster flush logic to related connection

* support Predis syntax in PhpRedis connection

translate Predis syntax to PhpRedis' `true` parameter

* fix types

* support async cluster flushing

* avoid null errors

* Update PhpRedisClusterConnection.php

Co-authored-by: Taylor Otwell <[email protected]>

Author: tillkruss

src/Illuminate/Redis/Connections/PhpRedisClusterConnection.php

@@ -4,5 +4,21 @@
 
 class PhpRedisClusterConnection extends PhpRedisConnection
 {
-    //
+    /**
+     * Flush the selected Redis database on all master nodes.
+     *
+     * @return mixed
+     */
+    public function flushdb()
+    {
+        $arguments = func_get_args();
+
+        $async = strtoupper((string) $arguments[0] ?? null) === 'ASYNC';
+
+        foreach ($this->client->_masters() as $master) {
+            $async
+                ? $this->command('rawCommand', [$master, 'flushdb', 'async'])
+                : $this->command('flushdb', [$master]);
+        }
+    }
 }

src/Illuminate/Redis/Connections/PhpRedisConnection.php

@@ -7,7 +7,6 @@
 use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 use Redis;
-use RedisCluster;
 use RedisException;
 
 /**
@@ -495,17 +494,17 @@ public function createSubscription($channels, Closure $callback, $method = 'subs
     /**
      * Flush the selected Redis database.
      *
-     * @return void
+     * @return mixed
      */
     public function flushdb()
     {
-        if (! $this->client instanceof RedisCluster) {
-            return $this->command('flushdb');
-        }
+        $arguments = func_get_args();
 
-        foreach ($this->client->_masters() as $master) {
-            $this->client->flushDb($master);
+        if (strtoupper((string) $arguments[0] ?? null) === 'ASYNC') {
+            return $this->command('flushdb', [true]);
         }
+
+        return $this->command('flushdb');
     }
 
     /**