Re: [PATCH] receive-pack: check object type of sha1 before using them as commits

Linus Torvalds [off-list ref] writes:

On Wed, 2 Jan 2008, Martin Koegler wrote:

quoted

 
-		old_commit = (struct commit *)parse_object(old_sha1);
-		new_commit = (struct commit *)parse_object(new_sha1);
+		old_object = parse_object(old_sha1);
+		new_object = parse_object(new_sha1);

I think it would be better to use

	old_object = lookup_commit_reference(old_sha1);
	if (!old_object)
		return "bad ref";
	new_object = lookup_commit_reference(new_sha1);
	if (!new_object)
		return "bad ref";

which will write a slightly more useful error message if it's not a commit 
(ie it will use the "check_commit()" function in commit.c)

Hmmm...  Three points.

 * lookup_commit_reference() is silent if the object pointed at
   by old/new SHA-1 is missing.

 * when storing in refs/heads, we do not want to have committish
   but we do want an actual commit object.

 * returning like that the user cannot tell which ref had the
   error.