[Bug 32438] New: winhttp:winhttp conformance test WinHttpGetProxyForUrl() failure

http://bugs.winehq.org/show_bug.cgi?id=32438

Bug #: 32438
           Summary: winhttp:winhttp conformance test
                    WinHttpGetProxyForUrl() failure
           Product: Wine
           Version: 1.5.19
          Platform: x86
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: winhttp
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]
    Classification: Unclassified

My laptop gets the following test failure (see the fg-acer64-* winetest
results):

winhttp.c:2700: Test failed: got 12166

I looked into this and what's special about it is that its fqdn is
'hawai.free.fr'. I'm not 100% sure how this happens but I think it makes sense
given that my ISP is free.fr so this is just the combination of the hostname
'hawai' and the default domain 'free.fr' (my other machines are on various
private domains).

This causes WinHttpDetectAutoProxyConfigUrl() to check if wpad.free.fr is
resolvable, which it is. So it succeeds and returns:

http://212.27.63.171/wpad.dat

The problem is that wpad.free.fr is hosted on a virtual web host(1). That is a
single web server with a single IP address hosts multiple web sites and uses
the Host field in the HTTP header to determine which site is being accessed. So
accessing this page by IP address fails while accessing it as
http://wpad.free.fr/wpad.dat succeeds.

This error then causes WinHttpGetProxyForUrl() to fail because the string it is
given to parse is an HTML HTTP 500 error page. I have confirmed that if
WinHttpGetProxyForUrl() return http://wpad.free.fr/wpad.dat the test succeeds.

So why does WinHttpGetProxyForUrl() use the IP address to build the URL?

On Windows I could not get WinHttpDetectAutoProxyConfigUrl() to return anything
but ERROR_WINHTTP_AUTODETECTION_FAILED. I suspect it gets a different domain
name somehow.

(1) https://en.wikipedia.org/wiki/Virtual_hosting#Name-based