On Thu, Mar 02, 2017 at 06:13:27PM +0000, Ian Jackson wrote:
> brian m. carlson writes ("Re: Transition plan for git to move to a new hash function"):
> > On Mon, Feb 27, 2017 at 01:00:01PM +0000, Ian Jackson wrote:
> > > Objects of one hash may refer to objects named by a different hash
> > > function to their own.  Preference rules arrange that normally, new
> > > hash objects refer to other new hash objects.
> > 
> > The existing codebase isn't really intended with that in mind.
> 
> Yes.  I've seen the attempts to start to replace char* with a hash
> struct.

My comment actually has nothing to do with the way struct object_id is
set up.  That actually can be trivially extended with a byte or two of
type.

Instead, I was referring to areas like the notes code.  It has extensive
use of the last byte as a type of lookup table key.  It's very dependent
on having exactly one hash, since it will always want to use the last
byte.

There are other, more subtle areas of the code that just don't handle
multiple hashes well.  Ideally we would remedy this, but I think
everyone is very eager to move away from SHA-1, and since nobody has
stepped up to volunteer to do that work, we should probably adopt a
solution that doesn't involve doing that.
-- 
brian m. carlson / brian with sandals: Houston, Texas, US
+1 832 623 2791 | https://www.crustytoothpaste.net/~bmc | My opinion only
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