Re: [PATCH] Don't dereference NULL upon lookup_tree failure.

[Junio C Hamano <gitster@pobox.com>]

Jim Meyering <jim@meyering.net> writes:

> Junio C Hamano <gitster@pobox.com> wrote:
> ...
>> Sorry, I asked for a wrong thing.  parse_object() reads and
>> finds out the type, so type there is presumably the right type
>> of the object (which is OBJ_TREE).  Then parse_object_buffer()
>> checks if it has already seen the object of the same SHA-1 and
>> finds that somebody had earlier told that SHA-1 name is of a
>> commit object.  Either you found a SHA-1 collision (highly
>> unlikely) or the earlier caller had lied.  And I think what
>> really needs to be fixed is that lying caller.  That is not in
>> the above call chain.
>
> I presume that parsecvs is the culprit, in constructing
> an invalid repository...

Independent of who creates a "invalid repository", our tools
should be prepared to be fed bad data and not get upset.
Somebody in our code read a non-commit (or it did not read
anything) and told the object layer it is a commit.  That
codepath needs to be tightened up, no?