Subject: Re: [PATCH 6/7] read-cache: refuse to create index referring to external objects

From: Junio C Hamano <[email-masked]>
Date: Sun, 27 Jan 2013 21:54:07 -0800

Duy Nguyen <[email-masked]> writes:

> On Sat, Jan 26, 2013 at 2:00 AM, Junio C Hamano <[email-masked]> wrote:
>> This is not a tangent, but if you want to go this "forbid making our
>> repository depend on objects we do not have but we know about after
>> we peek submodule odb" route [*1*], write_sha1_file() needs to be
>> told about has_sha1_file_proper().  We may "git add" a new blob in
>> the superproject, the blob may not yet exist in *our* repository,
>> but may happen to already exist in the submodue odb.  In such a
>> case, write_sha1_file() has to write that blob in our repository,
>> without the existing has_sha1_file() check bypassing it.  Otherwise
>> our attempt to create a tree that contains that blob will fail,
>> saying that the blob only seems to exist to us via submodule odb but
>> not in our repository.
>
> Another thing needs to be done for this to work. The current reading

For *what* to work???  I think the performance consideration is the
only thing that should drive the read-order; correctness should not
be affected.

> order is packs first, loose objects next. If we create a local loose
> duplicate of an alternate packed object, our local version will never
> be read. Regardless the submodule odb issue, I think we should prefer
> reading local loose objects over alternate packed ones.