Hi,

First of all, thanks@wtorsi for your time taking a look on this issue.

I have a similar issue when trying toPOST arrays using the HttpClient component together with Mime. Let's say I am trying to send an array of tags for creating a media file.

$formFields = ['media' => ['tags' => [            ['name' =>'first-tag'            ],            ['name' =>'first-tag'            ]        ],    ],];

Using the PR code, as result, I have the following field names:

name=medianame=media

However, when sending a form-data, what I expect on the backend is something like:

name=media[tags][0][name]name=media[tags][1][name]

I changed a bit the closure function to have the result I was expecting, which I am not sure it is the correct way.

$prepare =function ($item,$key,$root =null)use (&$values, &$prepare) {$fieldName =$root ?$root .'['.$key.']' :$key;if (\is_array($item)) {array_walk($item,$prepare,$fieldName);return;    }$values[] =$this->preparePart($fieldName,$item);};

Any thoughts?

Closing as it seems to have been fixed by#34032