clone: make sure we support the transport type

If we use an unsupported transport (e.g., http when curl
support is not compiled in), transport_get reports an error
to the user, but we still get a transport object. We need to
manually check and abort the clone process at that point, or
we end up with a segfault.

Noticed by Thomas Rast.

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-clone.c b/builtin-clone.c
index 4740b13..f4accbe 100644 (file)
--- a/builtin-clone.c
+++ b/builtin-clone.c
@@ -449,6 +449,9 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
                struct remote *remote = remote_get(argv[0]);
                struct transport *transport = transport_get(remote, argv[0]);
 
+               if (!transport->get_refs_list || !transport->fetch)
+                       die("Don't know how to clone %s", transport->url);
+
                transport_set_option(transport, TRANS_OPT_KEEP, "yes");
 
                if (option_depth)