First, a joke... since I can't tell jokes, I offer:
http://changelog.complete.org/posts/698-If-Version-Control-Systems-were-Airlines.html Fortunately, I won't be getting in to the Distributed Version Control Systems (DVCS) wars here... but I had a question about how Sage uses Hg.. and from the answers, (and after checking to make sure I didn't have this entirely wrong) I figured I'd bring it forward. My question is: Why are we using "hg clone" when doing development? Hg clone, basically, copies over an entire repository to a new location which, from a DVCS perspective, is only done when creating the local repository on a machine. Doing a clone of a "local" repository, basically, doesn't make sense from the perspective of a DVCS. The idea as practiced in Sage is, I think, that one can maintain the "original copy" and "development" areas separately... but, says I, that's the entire point of DVCS in general, and Hg in particular. So, I propose there's a misunderstanding of Hg and clone vs. branch. I claim that branching is a trivial operation, switching between branches is fast, and that the entire point of DVCS is lost with the clone operation. Furthermore, by cloning, we need to maintain symlinks and have code specifically written to manage the updating of the symlinks to no advantage. Furthermore, it takes time and space and reduces the effectiveness of tools (e.g. branch visualization) for doing what I think the intent of the clone is. -glenn P.S. Below is a broader discussion of the issue... WARNING: its entirely up to you whether you wanna get into this... and DVCS wars easily exceed politics and religion in the emotions and vitriol generated. The DVCS battle is currently between hg, bzr and git with hg giving up ground to bzr... and git being git <<<< opinion warning >>> IMHO, git is technically superior than the others but because Linus is such a "git" will likely not become mainstream... I personally believe there is a very intentional barrier to keep git users at the level of kernel hackers where folks pine for the day when you needed to be a hard core hacker to even dabble in linux... a cabal where only the anointed need apply. a shame, but such is life. to get an idea, check out Linus on git: http://www.youtube.com/watch?v=4XpnKHJAok8 and a much better follow up by Randall Schwarz which should have been titled: "What Linus means to say is:" http://www.youtube.com/watch?v=8dhZ9BXQgc4 <<< opinion end >>> So, the going-in assumption of any DVCS is that the developer always has a complete copy of the distro... whatever she wants to decide the distro is... although for most that will mean one of the "officially" tagged releases... and the DVCS system presents a specific "branch" to the user. To avoid terminology confusion: A "branch" is a particular path through the development tree. The tree has many branches at any point in time composed of the aggregate set of development activities of all developers and the merging which has taken place along the way throughout the DVCS spatio-temporal mesh. Some branches after a specific commit will be "tagged" as a release or as a specific starting point for a group activity to help coordinate. However, its critical to recognize that there is no central control in a DVCS... the importance of a tag or a release is only that to which the community assigns: a particular tag / user / repository is only important if you make it important. This is very much in contrast with CVS/SVN where there was a central managed system with clear lines of authority and permissions and security.... nope, DVCS is all about true meritocracy... I care about your branch cuz I trust you. In Sage's case, its when mabshoff or wstein or the other folks whom we all know... say so... because we trust them... not because they have the password. However, you can have both... since Sage cares about sagemath.org, it can be managed in such a way that a specific tag signed by the "usual suspects" means what we think it means. So, we have both kinds, centralized and distributed. Of course, one might argue that its the gpg signature that really matters, not sagemath.org... but I digress. To emphasize: DVCS allows untethered users complete flexibility to go off the reservation for very long periods of time... creating branches, committing changes etc... and allowing them to be merged back into ANY other DVCS repo within the DVCS mesh. Due to the magic of sha1 encoding, the paths are unambiguous... merging it all together if there's been no coordination is another matter... but that's a social not a technical issue. -glenn -- Glenn H. Tarbox, PhD || 206-494-0819 || [EMAIL PROTECTED] "Don't worry about people stealing your ideas. If your ideas are any good you'll have to ram them down peoples throats" -- Howard Aiken --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
