Re: Supressing sorting of trees

From: Shawn O. Pearce <spearce@spearce.org>
Date: Oct 12, 2009, 14:20 UTC
Message-ID: <20091012142032.GG9261@spearce.org>
In-Reply-To: <loom.20091012T152113-874@post.gmane.org>

Sal Mangano <smangano@into-technology.com> wrote:

Show 6 quoted lines

> I am using Git in a non-standard way and need to make a few twaeks in my 
> custom build. I have added a --nosort option to git mktree which will suppress
> the qsort of the tree. 
> 
> Will this break any other git functions? Are there any commands that assume 
> trees are always sorted?

_YES IT BREAKS GIT_.

You cannot do this.

A Git repository whose trees are not sorted according to the Git specific sort ordering is severly broken and most tools will fail horribly on it.

Almost all code which reads trees assumes the names are sorted in a specific order. These tools perform sorted merges against other tree like structures. If the names are out of order the merge will fail. `git fsck` will complain that the tree is not sorted properly. Tools like `git log -- foo.c` will fail randomly because they break out of the entry lookup as soon as they find a name that is after foo.c, as they assume the tree is sorted.

I could go on.  But there is no point.

Oh, and trust me when I say this, the tree sorting matters. Long ago JGit had a bug where it didn't sort trees correctly all of the time and we had a devil of a time tracking down that corruption.

-- 
Shawn.