Re: Deciding between Git/Mercurial

[Leo Razoumov <slonik.az@gmail.com>]

On 2009-09-29, Jakub Narebski <jnareb@gmail.com> wrote:
> On Tue, 29 Sep 2009, Leo Razoumov wrote:
>  > On 2009-09-28, Jakub Narebski <jnareb@gmail.com> wrote:
>  > > [..snip..]
>  > >  Besides with nonlinear history with
>  > >  revision numbers such as 12678 and 12687 you know that 12678 is older
>  > >  than 12687 if and only if 12678 and 12687 are on the same line of
>  > >  development.
>  >
>  > The statement above is incorrect!! In a Mercurial repo local revision
>  > numbers are strictly ordered in commit time. 12678 < 12687 means that
>  > 12678 was committed prior to 12687. But these two commits could belong
>  > to two completely unrelated lines of development.
>
>
> This is impossible with distributed development.  If the second branch
>  comes from other repository, with commits _created_ (in that repository)
>  earlier than commits in current repository, but commits in first
>  branch (from current repository) were created earlier than _fetching_
>  those commits in second branch:
>
>   .---.---.---.---x---1---2---3---M---.
>                    \             /
>                     \-A---B---C-/             <-- from repository B
>
>
>  Either you would have to change commits numbers, and therefore they would
>  be not stable, or you would have to change commit time to mean 'time this
>  commit got into current repository', which would kill performance for sure.
>

Jakub,
in Mercurial sequential commit numbers are local to a repo and are not
unique between the clones. Unique ID is SHA1 as in git. So mercurial
commit 127:aaf123453dfgdfgddd...
means commit number 127 in this repo with SHA1 "aaf123453dfgdfgddd..."
In another clone commit 127 might mean completely different thing.
Sequential commit numbers are strictly for "local convenience".

--Leo--