Mercurial 1.1 DVCS Released

http://selenic.com/pipermail/mercurial/2008-December/022670.html

by gecko • 18 years ago

33 7 18 years ago

You can see a full list of the new features at http://www.selenic.com/mercurial/wiki/index.cgi/WhatsNew. My favorites:

1. A real rebase command, rather than having to use quilt voodoo 2. bookmarks, git-style lightweight local branches (though git users beware, though bookmarks and local branches have the same functionality, their semantics are radically different (and speaking as a Mercurial user, I prefer git's, but whatever)) 3. Much more Windows-friendly repository format (and improvements to case-folding systems in general) 4. Vastly improved web interface

There's lots more, but having used the development version for the last several weeks, the above features are my favorites.

shutter• 18 years ago

Cool. The changelog lists lots of updates; I'd be interested to hear from those who have had more experience with Git as to whether this improves Mercurial's stance versus Git.

gecko3• 18 years ago

So, disclaimer: I'm a Mercurial fan.

There are two big things git has traditionally done better than Mercurial: lightweight branching, and rebasing. Both were possible in Mercurial using mq (plus qguards, in the case of lightweight branching), but the experience was rather clumsy. I didn't mind putting up with it, since, at the time the two systems came out, Mercurial was markedly easier to use than git. But, over the last year, git closed a lot of the usability gap, while Mercurial has held almost completely still, and that's resulted in a lot of arguments that Mercurial's time had passed, and git was the way to go.

The good news is that this release fully eliminates git's first advantage, and either eliminates, eliminates and beats, or fails to address the second, depending on where you're coming from. The easy news to process: the rebase extension enables full git-style rebasing, end of story. You can do an automatic pull and rebase via `hg pull --rebase`, if that's what you want, or you can do more customized rebasing via `hg rebase`. So that's done, and, based on my use in production environments, works very well.

Now, Mercurial 1.1 introduces real lightweight branching--no mq hackery--via an extension called `bookmarks`, which ships with Mercurial. These provide identical capabilities and benefits as git's local branches. The complicated discussion we can have revolves around bookmark semantics. bookmarks, like git branches, are basically "floating tags"--tags that mark a head in the repo's DAG, and that move with that head as you issue additional commits. The difference comes from the fact that bookmarks very directly expose what's going on, whereas git's branch command hides what's going on behind what I personally feel is a more intuitive UI. So, the argument is: is exposing what's actually going on better, because it gives you more power; equivalent, since the functionality provided is identical; or worse, because too much implementation is exposed in interface. I personally need more time to sort out preconceived bias of what micorbranching should look like, from the bookmark extension in particular.

yummyfajitas• 18 years ago

Ok, a question from a darcs guy who recently switched to hg:

What are the use cases for rebase and lightweight branching? I really don't understand why I should prefer rebase to simply pull + merge. Also, is lightweight branching just a performance hack, or is there more to it?

schacon• 18 years ago

Disclaimer: I'm a git fan.

Just to be clear - this does not have identical capabilities and benefits to gits branching model.

For one, it does not appear that you can push these branches, which means that you can't work on topic branches with anyone else.

Second, you can't _not_ push commits you have made under another 'bookmark' - in other words, you can't branch to try out some stuff, switch back to your main branch, do a fix and then push, without everyone getting all the crap in your 'try-out' branch. It may not be in the code that is checked out, but it is in the history, which does not look like it can be removed easily.

Also, it's awkward to use - you can't be working and then just create a bookmark, work some more, then go back to where you diverged easily - you have to create a new bookmark at the diverge point, which you have to look up. If you try to create two bookmarks at the same time (so one will stay where you where and the other will move forward) it will (for some reason) move both bookmarks forward (which is pretty confusing).

Apparently, the only way to _really_ do what git does with local branching is to do what the hg book recommends, which is to do a local clone. This takes orders of magnitude more time (depending on the repo), doubles the space taken up on disk and clutters your disk with a bunch of directories.

It may be slightly better than the local branches in hg in that it isn't recorded in the commit itself, but 'bookmarks' are very much not git branches.

Mercurial 1.1 DVCS Released

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