Subject: Re: [PATCH] diff: add a config option to control orderfile

From: Junio C Hamano <[email-masked]>
Date: Tue, 17 Sep 2013 11:06:07 -0700

"Michael S. Tsirkin" <[email-masked]> writes:

> On Tue, Sep 17, 2013 at 10:24:19AM -0700, Junio C Hamano wrote:
>> "Michael S. Tsirkin" <[email-masked]> writes:
>> 
>> > So might it not be useful to tweak patch id to
>> > sort the diff, making it a bit more stable?
>> 
>> That is one thing that needs to be done, I think.  But it would be
>> unfortunate if we have to do that unconditionally, though, as we may
>> be "buffering" many hundred kilobytes of patch text in core.  If we
>> can do so without regressing the streaming performance for the most
>> common case of not using the orderfile on the generating side (hence
>> not having to sort on the receiving end), it would be ideal.  I am
>> not sure offhand how much code damage we are talking about, though.
>
> So make it conditional on the presence of the orderefile option?

That would mean that those who set orderfile from configuration in
the future will have to always suffer, I would think.  Is that
acceptable?  I dunno.

Also, if the sender used a non-standard order, the recipient does
not know what order the patch was generated, and the recipient does
not use a custom orderfile, what should happen?  I thought your idea
was to normalize by using some canonical order that is not affected
by the orderfile to make sure patch-id stays stable, so I would
imagine that such a recipient who does not have orderfile specified
still needs to sort before hashing, no?