[Monotone-devel] another newbie question - nonlinear ordering

[Timothy Brownawell]

Argh. Forgot to set To: field to the list, instead of just Richard.

Tim

---------- Forwarded message ----------
From: Timothy Brownawell <address@hidden>
Date: Apr 20, 2005 3:07 PM
Subject: Re: [Monotone-devel] another newbie question - nonlinear ordering
To: "K. Richard Pixley" <address@hidden>


On 4/20/05, K. Richard Pixley <address@hidden> wrote:
> Start with an empty file, f0.  Apply some initial content, delta1.
>
> f0 + delta1 = f1
>
> It occurs to me that if I now apply a change, delta2, to this file,
> (tree, subtree, repository, whatever):
>
> f1 + delta2 = f2
>
> And then I back out that change by applying the inverse delta2, delta2',
> then:
>
> f2 + delta2' = f3 = f1.
>
> Since the hash for f3 and f1 will be identical, we can no longer talk
> meaningfully about a linear sequence of revisions.  That is, revision id
> = SHA1(f3) = SHA1(f1) no longer has a single ancestor nor is there
> necessarily even a deterministic path from f3 back to the empty file.
> f3 and f1 are different not in content, but only in ancestry.
>
> Is this history really lost in monotone?  Or how is this handled?

Well, a revision also includes ancestor information, so two revisions
with the same file contents will still be different, since they have
different ancestors.

   http://www.venge.net/monotone/docs/Historical-records.html

Tim