Segfault when cloning http:// without libcurl

Hi all

1.5.6.rc0.15.gd513 segfaults when attempting to clone from a http:// repository if compiled without libcurl:

(gdb) run clone http://repo.or.cz/r/git-homepage.git/ [..] error: git was compiled without libcurl support.

Program received signal SIGSEGV, Segmentation fault. 0x00000000 in ?? () (gdb) bt #0 0x00000000 in ?? () #1 0x080dd18d in transport_get_remote_refs (transport=0x814dbf0) at transport.c:795 #2 0x0805d24b in cmd_clone (argc=1, argv=0xbfda0ae8, prefix=0x0) at builtin-clone.c:461 #3 0x0804adbf in handle_internal_command (argc=2, argv=0xbfda0ae8) at git.c:249 #4 0x0804afa9 in main (argc=2, argv=0xbfda0ae8) at git.c:444 (gdb) up #1 0x080dd18d in transport_get_remote_refs (transport=0x814dbf0) at transport.c:795 795 transport->remote_refs = transport->get_refs_list(transport);

The underlying problem seems to be that at builtin-clone.c:160, no error checking is done on the output of transport_get():

	transport = transport_get(remote, ref_git_copy);
	for (extra = transport_get_remote_refs(transport); extra;
	     extra = extra->next)
		add_extra_ref(extra->name, extra->old_sha1, 0);

But transport_get() never sets the ->get_refs_list() member if libcurl wasn't enabled at compile time, cf. transport.c:738:

#ifdef NO_CURL
		error("git was compiled without libcurl support.");
#else
		ret->get_refs_list = get_refs_via_curl;
		ret->fetch = fetch_objs_via_curl;
		ret->push = curl_transport_push;
#endif

Some digging shows that at the time the above #ifdef was inserted (ccfc02a3), there was no builtin-clone.c, so the error checking probably got lost in the translation.

I'd attempt to write a patch, but it looks like I would have to read into a lot of code for a fairly trivial issue, so I hope someone can help me out with this...

- Thomas