Length in write has only been nullable since PHP8.0.

Author: lucasnetau

src/Query/TcpTransportExecutor.php

@@ -270,7 +270,11 @@ public function handleWritable()
             $errstr = isset($m[2]) ? $m[2] : $error;
         });
 
-        $written = \fwrite($this->socket, $this->writeBuffer, $this->writeChunk);
+        if ($this->writeChunk !== null) {
+            $written = \fwrite($this->socket, $this->writeBuffer, $this->writeChunk);
+        } else {
+            $written = \fwrite($this->socket, $this->writeBuffer);
+        }
 
         // Only report errors if *nothing* could be sent and an error has been raised, or we are unable to retrieve the remote socket name (connection dead) [HHVM].
         // Ignore non-fatal warnings if *some* data could be sent.