Content-Type header is lost when using the built in HTTP Basic Auth

[desjob]

Symfony version(s) affected: 4.4.x

Description
Content-Type header is lost when using the built in HTTP Basic Auth.
After the initial redirect response is followed, $request->getContentType() returns null.
Also, when inspecting the $_SERVER superglobal, the 'Content-Type' is no longer there.

When inspecting $_SERVER at the intial request (the one returning the redirect as part of the basic auth), the Content-Type is still there.

How to reproduce

1. use a default basic auth setup from https://symfony.com/doc/4.4/security/auth_providers.html#security-http-basic
2. create a Controller that is behind the basic auth firewall and:

    /**
     * @Route("/testapi", methods={Request::METHOD_GET})
     */
    public function getAllAction(string $resourceType, Request $request): Response
    {
        var_dump($request->getContentType());
        var_dump($_SERVER);
        die;
    }

3. use Postman to call /testapi

Possible Solution
no suggestions, as i'm not sure where this is going wrong.

Additional context
I'm using postman to call my endpoint and set the request header, and i was considering the option that postman could be the issue here. However, when using the Postman Console it shows me the 2 separate requests as part of the basic auth, and the second request still has the Content-Type header that I filled in. Also, if I add any other custom header (i.e. X-FOOBAR), it IS available when i dump it from my controller after logging in, so the exception seems to be specifically on the Content-Type header.

[xabbuh]

Can you create a small example application that allows to reproduce your issue?

[xabbuh]

I am going to close here for now due to the lack of feedback. Please let us know when you have more information and we can consider to reopen.