Socket.gethostbyname returns sockaddrs of wrong address family

Socket.gethostbyname doesn't behave like gethostbyname(3).

It can return multiple sockaddrs, this is expected, but they are NOT all
necessarily in the indicated address family:

On my system, OS x 10.3 with IPv6 enabled, I see:

Socket.gethostbyname "localhost"
=> ["localhost", [], 30, "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\001", "\177\000\000\001"]
                    ^^^^

30 == Socket::AF_INET6, but the second sockaddr is NOT an IPv6 sockaddr.

If you are familiar with the BSD socket APIs you will know that
getaddrinfo(3) returns a struct hostent, and that all the addrs in
struct hostent.h_addr_list are necessarily of the same family.

Generally, ruby's socket API reflects the system socket API, so I think
current behaviour is a bug.  It isn't a useful extension - a sockaddr
can't be used without knowing the type, and the second sockaddr is of
unspecified type.

The fix would be simple:

diff -u -r1.108.2.37 socket.c
--- socket.c  28 Nov 2005 09:56:45 -0000  1.108.2.37
+++ socket.c  30 Jan 2006 06:28:53 -0000
@@ -1250,7 +1250,14 @@
     rb_ary_push(ary, names);
     rb_ary_push(ary, INT2NUM(addr->ai_family));
     for (ai = addr; ai; ai = ai->ai_next) { 
+      /* Pushing all addresses regardless of address family is not the
+       * behaviour expected of gethostbyname(). All the addresses in struct
+       * hostent->h_addr_list must be of the same family, I think the following
+       * line would fix this.
+ 
+       if(ai->ai_family == addr->ai_family)  <-- suggested fix
+       */
        rb_ary_push(ary, (*ipaddr)(ai->ai_addr, ai->ai_addrlen));
     }
  
     return ary;

Cheers,
Sam