Re: [PATCH] Fixed crash in fetching remote tags when there is not tags.

Jeff King, Wed, Oct 10, 2007 07:10:35 +0200:

On Tue, Oct 09, 2007 at 08:20:43PM +0200, Alex Riesen wrote:

quoted

Your test does not crash on my system and your fix is obviously bogus.
Just take a look at the only call site of the tail_link_ref: ret
cannot be NULL. alloc_ref will crash in memset, if this were the case.

His work is almost certainly on top of next, which crashes reliably with
the test and has an additional call site for tail_link_ref. Aside from
some trailing whitespace in the patch, I think his fix is reasonable.

Ach, I see.

Still, I'd suggest move the test into the caller, firstly because it
is the only place that special. Also, I can't think of a proper reason
to add a NULL ref to a reflist, and so the crashing tail_link_ref will
help us find the callers which use tail_link_ref incorrectly
(illogically too).

As the result of patter expansion can be NULL (empty pattern, as it
seems), lets just check for it. I parked the patch below locally.

diff --git a/remote.c b/remote.c
index 5e92378..58d63ed 100644
--- a/remote.c
+++ b/remote.c

@@ -884,7 +884,8 @@ int get_fetch_map(struct ref *remote_refs,
 			    rm->peer_ref->name);
 	}
 
-	tail_link_ref(ref_map, tail);
+	if (ref_map)
+		tail_link_ref(ref_map, tail);
 
 	return 0;
 }