git-repack: Properly abort in corrupt repository

In a corrupt repository, git-repack produces a pack that does not
contain needed objects without complaining, and the result of this
combined with -d flag can be very painful -- e.g. a lossage of one
tree object can lead to lossage of blobs reachable only through that
tree.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

git-repack.sh

@@ -41,7 +41,7 @@ esac
 if [ "$local" ]; then
 	pack_objects="$pack_objects --local"
 fi
-name=$(git-rev-list --objects $rev_list $(git-rev-parse $rev_parse) |
+name=$(git-rev-list --objects $rev_list $(git-rev-parse $rev_parse) 2>&1 |
 	git-pack-objects --non-empty $pack_objects .tmp-pack) ||
 	exit 1
 if [ -z "$name" ]; then

pack-objects.c

@@ -524,7 +524,7 @@ int main(int argc, char **argv)
 		unsigned char sha1[20];
 
 		if (get_sha1_hex(line, sha1))
-			die("expected sha1, got garbage");
+			die("expected sha1, got garbage:\n %s", line);
 		hash = 0;
 		p = line+40;
 		while (*p) {