Re: What's cooking in git.git (Jun 2010, #04; Wed, 23)

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 24, 2010, 22:48 UTC
Message-ID: <7vtyosnj23.fsf@alter.siamese.dyndns.org>
In-Reply-To: <40D1B374-E80A-4BA2-B3A2-142E8256C23E@gmail.com>

Eyvind Bernhardsen <eyvind.bernhardsen@gmail.com> writes:

Show 19 quoted lines

> On 24. juni 2010, at 22.21, Junio C Hamano wrote:
>
>> Finn Arne Gangstad <finnag@pvv.org> writes:
>> 
>>> If .gitattributes is different on the different sides, or if you
>>> enable autocrlf, the current repo contents may change after
>>> git-to-worktree and worktree-to-git again.
>> 
>> IOW, g2w-then-w2g may not be an identity function.
>> 
>> If we were to encourage use of this codepath to wider audiences, we may
>> need to have a document for people who write smudge/clean filters.  In
>> order for the result to be stable, applying g2w-then-w2g once again on top
>> of the result of running g2w-then-w2g on anything should be no-op, no?
>
> Hm.  Isn't that already a requirement?  If a clean filter doesn't clean
> to something normalized, simply touching a file could result in spurious
> differences (much like pre-safe-autocrlf autocrlf).  I could well be
> missing something here, though.

A natural expectation would be that g2w-then-w2g is an identity function, I think. But the "feature" under discussion in this thread depends on that g2w-then-w2g is _not_ a noop (otherwise it wouldn't do us any good).

IOW, we are suggesting authors of clean/smudge to make their g2w-then-w2g perform more than just a round-trip but actively _clean things up_, aren't we? I don't think we have documented that suggestion, and I actually think we might even have said that g2w-then-w2g should be a no-op somewhere in the documentation.