[Bug 54413] ws2_32:sock - DuplicateHandle(socket) sometimes look like a socket in test_WSAGetOverlappedResult() on Windows

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=54413

--- Comment #3 from Zeb Figura  ---
Socket handles *are* NT handles, which is why you can duplicate them. The way
it actually (seems to) work is that they have some in-process data as well. I'm
not sure what this in-process data comprises—we don't store any—but it may
simply have to do with layered service providers (which we don't implement).

Hence if you just create an NT socket handle in a target process, ws2_32 won't
know about it, and will conclude it's not a socket when trying to look it up.
In order to tell ws2_32 about it you're supposed to use WSADuplicateSocket()
instead of DuplicateHandle() and then import it on the other end with
WSASocket(). (Internally WSADuplicateSocket() seems to just call
DuplicateHandle() and stash the socket handle in the returned struct.)

Which all makes this test failure very confusing—how did ws2_32 find out about
this socket?