Re: [PATCH] branch: don't assume the merge filter ref exists

On Mon, Feb 27, 2012 at 04:11:53PM +0100, Carlos Martín Nieto wrote:

print_ref_list looks up the merge_filter_ref and assumes that a valid
pointer is returned. When the object doesn't exist, it tries to
dereference a NULL pointer. This can be the case when git branch
--merged is given an argument that isn't a valid commit name.

Check whether the lookup returns a NULL pointer and die with an error
if it does. Add a test, while we're at it.

Signed-off-by: Carlos Martín Nieto <redacted>
---

It certainly looks like --merged was only ever supposed to be used
with branch names, as it assumed that get_sha1() would catch the
errors.

I'm not sure if "bad object" or "invalid object" fits better. "bad
object" might have a stronger implication that it exists but is
corrupt.

You would also get NULL if the object exists but is not a commit. Maybe:

  die("object '%s' does not point to a commit", ...)

would be better? It covers the wrong-type case, and is still technically
true when the object does not exist.

-Peff