Re: [PATCH] Additional merge-base tests

Johannes Schindelin wrote:

Hi,

On Tue, 4 Jul 2006, Junio C Hamano wrote:

quoted

Johannes Schindelin [off-list ref] writes:

quoted

We could introduce a time.maximumSkew variable, and just walk only 
that much further when traversing the commits.

We could have had "commit generation number" in the commit
object header, and use that instead of commit timestamps for
these traversal purposes.  The generation number for a commit is
defined to be max(generation number of its parents)+1 and we
prime the recursive this definition by defining the generation
number for the root commit to be one.

Are you really, really sure this is a remedy? I, for one, am quite sure of 
the opposite. What you propose is just another time scale, only this time, 
it is not universally true (not even minus local incompetence to keep the 
clock accurate).

It works[*] and it does what using the timestamp was trying to do. 
Namely, work from "more recent" (or "closer") commits toward "older" (or 
"farther") commits until you've gone past the point you care about.

It's a little late to be changing the structure of a commit and you'd 
have to deal with some size/scale issues, but it's do-able. A better 
idea may be to generate and keep the generation number on a per 
repository basis, and you'd be able to work around changing grafts.

[*] Grafts do _really_ nasty things to this. Just like clock skew does now.