Re: [RFC] [PATCH 0/5] Implement 'prior' commit object links (and other commit links ideas)

From: Linus Torvalds <torvalds@osdl.org>
Date: Apr 25, 2006, 17:11 UTC
Message-ID: <Pine.LNX.4.64.0604251004410.3701@g5.osdl.org>
In-Reply-To: <e2lijt$aco$1@sea.gmane.org>

On Tue, 25 Apr 2006, Jakub Narebski wrote:

> 
> The generic commit links "related" which is fsck-able at least and "note"
> which is not. It is idea somewhat on the level of providing _extended
> attributes_ in VFS in Linux kernel, IMVHO.

And nobody actually uses extended attributes either, do they?

Plus it's _not_ fsck'able, since the thing doesn't even have any valid semantics. You guys can't even agree on whether the object must exist or not.

Anyway, I'm not interested. I'm violently opposed to the mess that is darcs and other crapola. The WHOLE point of git is to have well-defined semantics and get away from the horrors that other systems have done, where they have allowed any random crap to "make sense".

If you want darcs-like semantics where there are no rules, just use darcs, for chrissake! And if you want to base it on git because you've noticed that git is (a) stable, (b) fast and (c) has developed remarkably well, then think for a second _why_ git is stable, fast, and well-developed. It's that exactly because it has clear semantics, and no room for random crud.

Git tracks contents, and the well-defined history of how those contents came to be. Git does NOT track "additional notes" left by the developer that have weak semantics. Git does not track when a developer says "I renamed a file".

For exactly the same reason, git should not track it when a developer says "I think this commit is related to that commit". It's not hard data, that has hard and clear semantics.

Once you start adding data that has no clear semantics, you're screwed. At that point, it's a "track guesses" game, not a "track contents" game.

			Linus