BasicAuthentication in combination with a sessionId is broken - after the first login following page refreshs fail with bad credentials.

Here my analysis (I commented this on the corresponding commit on github as well):
The BasicHeaderProcessor expects a not null Authentication Object

From BasicHeaderProcessor:

Authentication auth = a.authenticate(req, rsp, username, password);
if (auth!=null) {
LOGGER.log(FINE, "Request authenticated as

by

", new Object[]

);
success(req, rsp, chain, auth);
return;
}
From BasicHeaderRealPasswordAuthenticator:

if (!authenticationIsRequired(username))
return null;
It seems that you need to return the existing authentication Object from BasicHeaderRealPasswordAuthenticator and not null if the current authentication is already valid...?

Anyway since we are running jenkins through a proxy with basicAuth the current version is completely broken for us...

Corresponding Github commit: https://github.com/jenkinsci/jenkins/commit/b2a98f6bc6924d1fd25f7da583888c2f4f36d83c