Re: Questions about the hash function transition

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Aug 28, 2018, 17:11 UTC
Message-ID: <20180828171113.GA23314@aiede.svl.corp.google.com>
In-Reply-To: <nycvar.QRO.7.76.6.1808281402510.73@tvgsbejvaqbjf.bet>

Hi,

Johannes Schindelin wrote:

> On Thu, 23 Aug 2018, Jonathan Nieder wrote:
> > Ævar Arnfjörð Bjarmason wrote:

Show 13 quoted lines

>>> Are we going to need a midx version of these mapping files? How does
>>> midx fit into this picture? Perhaps it's too obscure to worry about...
>>
>> That's a great question!  I think the simplest answer is to have a
>> midx only for the primary object format and fall back to using
>> ordinary idx files for the others.
>>
>> The midx format already has a field for hash function (thanks,
>> Derrick!).
>
> Related: I wondered whether we could simply leverage the midx code for the
> bidirectional SHA-1 <-> SHA-256 mapping, as it strikes me as very similar
> in concept and challenges.

Interesting: tell me more.

My first instinct is to prefer the idx-based design that is already described in the design doc. If we want to change that, we should have a motivating reason.

Midx is designed to be optional and to not necessarily cover all objects, so it doesn't seem like a good fit.

Thanks, Jonathan