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Re: Strange message from "bzr pull"


From: Óscar Fuentes
Subject: Re: Strange message from "bzr pull"
Date: Wed, 30 Dec 2009 00:32:56 +0100
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1.90 (gnu/linux)

Eli Zaretskii <address@hidden> writes:

[snip]

>> Nobody that reads that document knows that the key information that
>> makes DVCS possible is what you see with
>> 
>> bzr log --show-ids
>
> And why is that information important?

Distributed version control is about exchanging revisions. You need a
way to know what revisions you are missing from some other branch, and a
way to know how the revisions are arranged. Those unique revision-ids
are the solution. A branch is, essentially, a set of revisions arranged
on a DAG. As far as Bazaar is concerned, the revision-id of a revision
(and the revision-ids of its parents) is the interesting info.

The revision number (revno) is only meaningful for a given branch or a
mirror of it. Some tools, like git, do not try to use revision numbers
and use the revision-id instead. This is the Right Thing but too much
people think that those long unique ids are too cumbersome, so Bazaar
and Mercurial have revision numbers too.

Hence, when someone says "revision 98834 broke the build" he must take
care of referring to the master trunk, and you shall look at that
revision number on your local mirror of trunk, because other branches
may have different numeration. But if you say "revision
address@hidden broke the build" you can
see the changes it introduced on any branch with

bzr diff -c revid:address@hidden

> More to the point, where _is_ it described?

No idea. But the above description should suffice for our purposes.

> What I see is this:
>
>     revno: 99212 [merge]
>     revision-id: address@hidden
>     parent: address@hidden
>     parent: address@hidden

This revision has two parents because it is a merge point. I'm sure you
get the idea.

[snip]

-- 
Óscar





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