Subject: Re: potential improvement to 'git log' with a range

From: Jakub Narebski <[email-masked]>
Date: Sun, 11 Apr 2010 14:32:49 -0700 (PDT)

Linus Torvalds <[email-masked]> writes:

> On Fri, 9 Apr 2010, Aghiles wrote:
> > 
> > Oh, I should have read the documentation. I was certain that ".." stands
> > for a range but it is a ... complement.
> 
> Well, technically ".." means two different things
> 
>  - for "set operations" (ie "git log" and friends) it's the "relative 
>    complement" of two sets (or "'reachable from A' \ 'reachable from B'").
> 
>  - for "edge operations" (ie "git diff" and friends) it's just two 
>    end-points (aka "range"). A diff doesn't work on sets, it only works on 
>    the two endpoints.

[...]
> Most SCM's really talk about "ranges". Once you think in those terms, 
> complex history doesn't work. Git very fundamentally is much about set 
> theory, and "ranges" is a bad word to use.

For example from I have got from asking on #mercurial IRC channel on
FreeNode (a bit of self promotion: I have done this research to write
an answer to "Git and Mercurial - Compare and Contrast" question on
StackOverflow[1]), Mercurial implements its ".." equivalent in the
term of _numeric range_, even for "hg log" (sic!).  It turns revision
identifiers used in range (-r <rev1>:<rev2>) to LOCAL number of
revision, and generates range based on numeric range, IIRC inclusive
on both sides (in Git range is exclusive from bottom, inclusive from
top).

Which is plain useless for anything but linear subsets of history
(compare e.g. "master..next", which in Git shows everything in "next"
that is not in "master"; "master" and "next" are not direct
descendants of one oanother, at least not usually).

[1] http://stackoverflow.com/questions/1598759/git-and-mercurial-compare-and-contrast/1599930#1599930

P.S. I wonder if Mercurial development list is subscribe-only...
-- 
Jakub Narebski
Poland
ShadeHawk on #git