Re: newbie questions about git design and features (some wrt hg)

On Friday, 02 February 2007 at 11:42, Linus Torvalds wrote:

On Fri, 2 Feb 2007, Brendan Cully wrote:

quoted

I don't think I do, no. (Maybe it's the double negative construction.)
Local tags don't get pushed. Tags on private branches don't get
pushed. Tags on public branches do. This business you describe, where
you push tags around completely separate from the revisions they tag,
sounds a little odd. But nothing stops you from maintaining your local
tags in their own repository, if that's what makes you happy.

quoted

In other words, tags are just like branches. You don't tie two tags 
together, because one may (and does) make sense without the other.

Which tags are being tied together?

If you tie "tag" together with "history", and push out history, what 
happens?

The public tags on the public history get pushed. This still sounds to
me like the right thing.

quoted

It seems to me they clearly do have history.

No they don't. Quite often, tags are generated outside of history, ie you 
tag something as being "known bad" long after it was done. Or you 
(hopefully) tag it with the test-information after it passed (or 
didn't) pass some debug check. Neither of which is something you'd do when 
the thing is actually committed or developed.

So tags are *events*. But if you think they are events "within" the 
history of a tree, you're missing a big issue.

Your distinction between "history" and "events" is unclear to
me. What's history if not a series of events?

Just because a tag is created at a different time than the revision it
tags, that doesn't mean that it is ahistorical. It's still interesting
to know what the state of the repository was when the tag was
created.

My personal use of tags tends to be
 - I tag releases I make, and sign them etc.
 - when debugging (and using "git bisect" in particular), I tag things for 
   my own memory (ie if a bisection selected something that didn't 
   compile, and I have to pick another point by hand, I tag that bad one 
   temporarily for explanation - the tag shows up nicely in the graphical 
   history viewers)

Mercurial supports local tags too. As far as I can tell, these
unversioned tags are about equivalent to git tags. They could
certainly be used for your bisection scenario.

I want tags to be useful for *anybody*. A total non-developer, who decides 
that he wants to test a release, should be able to tag the particular 
versions he happened to test, and it damn well shouldn't be just 
"my-tag-1023". It should allow him to write a small story about what the 
results of the tests were!

Which is how git tags are desiged. They're separate from history, but that 
doesn't make them less useful - it makes them *more* widely useful.

Mercurial supports both, because both are useful.