Re: [PATCH 1/7] sha1_file: keep track of where an SHA-1 object comes from

> On Fri, Jan 25, 2013 at 12:45 AM, Junio C Hamano <gitster@pobox.com> wrote:
>>>  How about this way instead: we keep track of where objects come from
>>>  so we can verify object source when we create or update something
>>>  that contains SHA-1.
>>
>> The overall approach taken by this series may be worth considering, but
>> I do not think the check implemented here is correct.
>>
>> An object may be found in an alternate odb but we may also have our
>> own copy of the same object.  You need to prove that a suspicious
>> object is visible to us *ONLY* through add_submodule_odb().
>
> The way alt odbs are linked (new odbs area always at the end), if we
> have the same copy, their copy will never be read (we check out alt
> odbs from head to tail). So those duplicate suspicious objects are
> actually invisible to us.