[PATCH 0/2] fix clone guess_dir_name regression in v2.4.8

[Jeff King <peff@peff.net>]

On Tue, Aug 04, 2015 at 06:42:46PM -0400, Jeff King wrote:

> > I did not intend this change in behavior, and I can confirm that
> > reverting my patch restores the original behavior. Thanks for bringing
> > this to my attention, I'll work on a patch.
> 
> I think this regression is in v2.4.8, as well. We should be able to use
> a running "len" instead of the "end" pointer in the earlier part, and
> then use strip_suffix_mem later (to strip from our already-reduced
> length, rather than the full NUL-terminated string). Like this:

Looks like "git clone --bare host:foo/.git" is broken, too. I've added
some tests to cover the recently broken cases, as well as some obvious
normal cases (which the patch I sent earlier break!). And as a bonus, we
can easily cover Patrick's root-repo problems (so people will actually
run the tests, unlike the stuff in t1509. :) ).

> @@ -167,14 +166,14 @@ static char *guess_dir_name(const char *repo, int is_bundle, int is_bare)
>  	 * the form  "remote.example.com:foo.git", i.e. no slash
>  	 * in the directory part.
>  	 */
> -	start = end;
> +	start = repo + len;
>  	while (repo < start && !is_dir_sep(start[-1]) && start[-1] != ':')
>  		start--;
>  
>  	/*
>  	 * Strip .{bundle,git}.
>  	 */
> -	strip_suffix(start, is_bundle ? ".bundle" : ".git" , &len);
> +	strip_suffix_mem(start, &len, is_bundle ? ".bundle" : ".git");

This is crap, of course. Our "len" variable is computed from the start
of "repo", of which "start" is a subset. So we are indexing way out of
bounds here.

As it turns out, this actually makes things simpler. We can stop using
"len" entirely in the early part, and leave it as-is with pointer math
(the patch I sent earlier did not really make anything simpler, anyway).
And then we can just compute the length of "start" here, minus
everything we've stripped off the end (i.e., "len = end - start").

Here are the patches.

  [1/2]: clone: add tests for output directory
  [2/2]: clone: use computed length in guess_dir_name

-Peff