Subject: Re: Honoring a checked out gitattributes file

From: Kristian Amlie <[email-masked]>
Date: Wed, 28 Jan 2009 18:25:13 +0100

Michael J Gruber wrote:
> I think there's a general time ordering problem. Say you do the
> following commits:
> 
> A: add a.txt
> B: add a .gitattributes file covering *.txt (say with crlf or any filter)
> C: add c.txt
> 
> Now, with an empty dir, you do either
> 
> 1) checkout A, B, C sequentially
> 2) checkout C
> 
> The contents of the checkout will be different in cases 1) and 2):
> 1) a.txt is checked out out as is, c.txt according to the attributes
> 2) with current git: probably like 1), with your suggestion: both a.txt
> and c.txt filtered according to the attributes.
> 
> If you add a file and .gitattributes covering it in the same commit
> there is an ordering ambiguity which can be solved (patched away)
> easily, but I think the difference between 1) and 2) is still
> problematic, and would need to be dealt with.

I agree.

> 
> The main problem seems to be that changing a file like gitattributes can
> potentially change (by changing filters) the contents which should be
> stored for a different file even if the checkout of that file doesn't
> change.

Yes, that is a problem. Ideally, the crlf attribute would be tied to the
file entry itself rather than a separate file (so changing the attribute
would mean a change to the file), but I guess we are stuck with what we
have.

I still think that case 2) is the most common, and fixing it has the
appealing property that if the repository line endings are broken for
some reason (because of case 1 or something else), then recloning or
checking out from scratch is guaranteed to bring the working tree into
the "correct" state.

Since fixing both cases is a pretty big task and fixing only case 2 is
small, I propose that we go ahead with that.

--
Kristian Amlie