[svn.haxx.se] · SVN Dev · SVN Users · SVN Org · TSVN Dev · TSVN Users · Subclipse Dev · Subclipse Users · this month's index

Re: Tags and branches are NOT the same

From: Julian Foad <julianfoad_at_btopenworld.com>
Date: 2006-03-19 12:00:33 CET

John Calcote wrote:
> On 2006-03-18 at 14:34:32 Julian Foad wrote:
> >
> > Unfortunately not, because you have fallen into the same trap as so many other
> > correspondents, and that is to approach the subject with the assumption that it
> > is conceptually simple, having an obvious Right Answer. The "solution" you
> > mention here is that a "tag" should be an alias name for a revision number.
>
> I don't know Julian, it seems conceptually simple to me, according to
> the CVS manual [...], tags seem to be
> just symbolic names for revision numbers. Section 4.4 is entitled, "Tags
> - Symbolic Revisions", which seems to convey the very simple three-word
> definition that I used in my original note, which you strongly state is
> not the case.

That's the case for CVS. Subversion is not CVS. One particularly pertinent
difference is that a CVS revision number is per file, whereas in Subversion a
revision number is across the whole repository. This difference has more than
trivial implications.

[...]
> > You don't even acknowledge in this mail that there are other possible
> > definitions, such as a tag marking only a subset of the files and
> > directories in the repository, which is something that CVS tags can do.
>
> I'm sorry if I wasn't clear on this point in my original message. I'm
> not really interested in possible new interpretations of the concept of
> tagging. Granted there is probably value in doing a use-case study as
> you suggest, but my original point was that existing CVS users expect
> tags to act as symbolic names for specific revisions of file sets.

Ah, I see. (That was't clear before, as you didn't mention CVS except in the
negative. Apology accepted.)

In contrast, the Subversion team is not really interested in just implementing
something that is as close as possible to the CVS concept of tagging without
thinking about whether that is the best concept for Subversion, nor in
providing Subversion with two different ways of tagging without very good
reason. There may be good reasons for supplementing or changing Subversion's
tagging abilities, but they have not been adequately studied and justified.

[...]
> In fact, I didn't provide a complete user
> experience in my examples. This surely needs to be done, but it's likely
> not that hard.

I love it when people say that. :-) Actually, you're probably right in that
collecting a fairly comprehensive set of use cases should require only a few
hours of one person's time plus maybe a fortnight or so of collecting examples
from other people. Indeed, I'm pretty sure a partial collection exists in the
mailing list archive as part of a previous discussion. Analysing those use
cases and arguing about whether they should be supported directly or whether
the user should be taught a new way to achieve the same goal is likely to take
longer.

> > I know I'm being harsh on you, but this is the way your message comes
> > across after having seen many others like it. Bear with me a minute.
> I don't mind you being harsh - I only mind being ignored, because then
> no intelligent exchange of ideas can happen. :)

OK. I'm sorry that all I can offer at the moment is an invitation for you or
someone else to study the requirements, arguments and proposals that have been
made so far and present them in a coherent form to enable further progress.

- Julian

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@subversion.tigris.org
For additional commands, e-mail: dev-help@subversion.tigris.org
Received on Sun Mar 19 12:00:54 2006

This is an archived mail posted to the Subversion Dev mailing list.

This site is subject to the Apache Privacy Policy and the Apache Public Forum Archive Policy.