HEAD request has warning "Redirect to ... expects a GET, but DownloadHandler is not set"

Unity Engine
,
1

I try to get the file size of an archive on GitHub, for example
https://github.com/UltraStar-Deluxe/songs-stream/archive/refs/heads/main.zip

Therefor, the following code runs in a coroutine:

using UnityWebRequest request = UnityWebRequest.Head(url);

Debug.Log("Before");
yield return request.SendWebRequest();
Debug.Log("After");

if (request.result
    is UnityWebRequest.Result.ConnectionError
    or UnityWebRequest.Result.ProtocolError)
{
    Debug.LogError($"Error fetching size: {request.error}");
}
else
{
    string contentLength = request.GetResponseHeader("Content-Length");
    Debug.Log("contentLength: " + contentLength);
}

“Before” is always reached, but “After” is sometimes not reached immediately.

I see a warning in the console coming from request.SendWebRequest()

Redirect to https://codeload.github.com/UltraStar-Deluxe/songs-stream/zip/refs/heads/main expects a GET, but DownloadHandler is not set

What is this warning about? Does the HEAD request not follow redirects?
As it is now, the file size is obtained sometimes successfully and sometimes not.

Is there a better way to query the file size of an archive of a GitHub repo?

2

It’s a bug that has been fixed, though fairly recently, so not all release streams have it.
A workaround is to attach download handler to your request.