Re: [Haskell-cafe] Make your Darcs repositories hashed?
Hey Haskellers (and darcs-users CC'ed) On Sat, Oct 09, 2010 at 23:08:12 +, Jason Dagit wrote: I answered you immediate question in a different email. Now I'll do a bit of explanation on why people want hashed. Thanks to Jason for the explanation. I've linked to it from http://wiki.darcs.net/RepositoryFormats so that we'll have an easier time in the future encouraging people to move to the hashed format. Also: If you don't have darcs 2.4.4, you can upgrade to the hashed format by doing: cd /srv/code/myrepo darcs get . ~/myrepo-hashed rm -rf ~/myrepo-hashed/_darcs/prefs cp -R _darcs/prefs ~/myrepo-hashed/_darcs/prefs mv ~/myrepo-hashed/_darcs _darcs.new mv _darcs _darcs.old mv _darcs.new _darcs rm -rf ~/myrepo-hashed rm -rf _darcs.old I may put this on the wiki. We had pruned this sort of thing away in favour of the optimize --upgrade command, in the interest of tidiness, but getting recent Darcs into people's hands takes a while. Also, the maintainers behind code.haskell.org are aware about the need for a Darcs 2.4.4 upgrade (I filed a request on 15 Sep). We're looking into an easy way to do this on Debian Etch. See also * http://wiki.darcs.net/RepositoryFormats The three formats in a nutshell * http://wiki.darcs.net/DarcsTwo#hashed-repository-format More about hashed repositories (covers a lot of the same stuff Jason did) * http://lists.osuosl.org/pipermail/darcs-users/2010-August/024941.html Discussion on eventually retiring support for old-fashioned repositories I can guarantee that at least Darcs 2.5 (the upcoming release) will continue to provide full support for old-fashioned repositories. But they are going away eventually so that we can focus on making Darcs better. Thanks! -- Eric Kow http://www.nltg.brighton.ac.uk/home/Eric.Kow For a faster response, try +44 (0)1273 64 2905 or xmpp:ko...@jabber.fr (Jabber or Google Talk only) signature.asc Description: Digital signature ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Make your Darcs repositories hashed?
Every Darcs repository I've pulled this year has always showed me this message: *** Fetching a hashed repository would be faster. Perhaps you could persuade the maintainer to run darcs optimize --upgrade with darcs 2.4.0 or higher? *** Maintainers! Please run darcs optimize --upgrade ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Make your Darcs repositories hashed?
The darcs installed on code.haskell.org is still version 2.02. It doesn't know about 'optimize --upgrade'. How do I upgrade those repositories? On Sat, Oct 9, 2010 at 2:30 PM, Christopher Done chrisd...@googlemail.com wrote: Every Darcs repository I've pulled this year has always showed me this message: *** Fetching a hashed repository would be faster. Perhaps you could persuade the maintainer to run darcs optimize --upgrade with darcs 2.4.0 or higher? *** Maintainers! Please run darcs optimize --upgrade ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Make your Darcs repositories hashed?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/9/10 08:30 , Christopher Done wrote: Every Darcs repository I've pulled this year has always showed me this message: *** Fetching a hashed repository would be faster. Perhaps you could persuade the maintainer to run darcs optimize --upgrade with darcs 2.4.0 or higher? *** The problem with this message is that it knows that *you* have a darcs that can take advantage of it, but no way to know if other users of the repository can (or, for that matter, if the repository is managed by a capable version of darcs). - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkyw52oACgkQIn7hlCsL25XbLACg0SE1NAbQKkKYY5pCQWQxRJLy noQAoNRlwRCDC78R2Sroo5rq1GkX59+L =FcxO -END PGP SIGNATURE- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Make your Darcs repositories hashed?
On Sat, Oct 9, 2010 at 3:06 PM, Brandon S Allbery KF8NH allb...@ece.cmu.edu wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/9/10 08:30 , Christopher Done wrote: Every Darcs repository I've pulled this year has always showed me this message: *** Fetching a hashed repository would be faster. Perhaps you could persuade the maintainer to run darcs optimize --upgrade with darcs 2.4.0 or higher? *** The problem with this message is that it knows that *you* have a darcs that can take advantage of it, but no way to know if other users of the repository can (or, for that matter, if the repository is managed by a capable version of darcs). Welcome to the world of distributed computing :) In general, you can't really tell what others are doing with their copies of the repository. It's both good and bad. Newer darcs clients are compatible with repos created with older darcs clients and using the newer client will not interfere with using the older clients on that repo. In other words: It's safe to use the newer clients. So you can think of your repo as being managed by the latest stable release if you like. The Haskell.org server doesn't have to be upgraded. Maintainers can install a newer darcs locally (cabal install darcs), do the upgrade locally and then copy the repository back to the haskell.org server. Or, if haskell.orgservers upgrade their copy of darcs, or you install newer darcs in your home dir, you can do the upgrade in-pace. Some things to keep in mind: * Darcs 2.4.4 is perfectly backwards compatible with older darcs and older repos. * cabal install makes upgrading/installing darcs painfree. * Newer darcs has fewer bugs and the performance continues to improve as well[1]. The over arching theme is: It is safe to upgrade your darcs client and you shoud upgrade your darcs client. If you have specific questions or concerns, I'd recommend asking on the darcs-users mailing list[2]. Thanks, Jason [1] If you poke around on this page following links you can get a feeling for how performance changes between releases: http://wiki.darcs.net/Benchmarks 2.4.4 is a solid release. [2] http://lists.osuosl.org/mailman/listinfo/darcs-users ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Make your Darcs repositories hashed?
On Sat, Oct 09, 2010 at 03:43:42PM -0700, Jason Dagit wrote: The Haskell.org server doesn't have to be upgraded. Maintainers can install a newer darcs locally (cabal install darcs), do the upgrade locally and then copy the repository back to the haskell.org server. Really? But then the version of darcs on code.haskell.org wouldn't be able to read those repositories, which would cause darcs over ssh to fail -- wouldn't it? Or am I missing something? -Brent ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Make your Darcs repositories hashed?
On Sat, Oct 9, 2010 at 8:52 PM, Brent Yorgey byor...@seas.upenn.edu wrote: On Sat, Oct 09, 2010 at 03:43:42PM -0700, Jason Dagit wrote: The Haskell.org server doesn't have to be upgraded. Maintainers can install a newer darcs locally (cabal install darcs), do the upgrade locally and then copy the repository back to the haskell.org server. Really? But then the version of darcs on code.haskell.org wouldn't be able to read those repositories, which would cause darcs over ssh to fail -- wouldn't it? Or am I missing something? You'd be fine. I tried to make this clear by saying: Some things to keep in mind: * Darcs 2.4.4 is perfectly backwards compatible with older darcs and older repos. In particular, the manual[1] says: The --upgrade option for darcs optimize performs an inplace upgrade of your repository to the latest compatible format. Right now means that darcs 1 old-fashioned repositories will be upgraded to darcs-1 hashed repositories (and notably, not to darcs 2 repositories as that would not be compatible; see darcs convert). Jason [1] http://darcs.net/manual/node7.html#SECTION00784000 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Make your Darcs repositories hashed?
On Sat, Oct 9, 2010 at 8:52 PM, Brent Yorgey byor...@seas.upenn.edu wrote: On Sat, Oct 09, 2010 at 03:43:42PM -0700, Jason Dagit wrote: The Haskell.org server doesn't have to be upgraded. Maintainers can install a newer darcs locally (cabal install darcs), do the upgrade locally and then copy the repository back to the haskell.org server. Really? But then the version of darcs on code.haskell.org wouldn't be able to read those repositories, which would cause darcs over ssh to fail -- wouldn't it? Or am I missing something? I answered you immediate question in a different email. Now I'll do a bit of explanation on why people want hashed. I should also mention that darcs 2.0.2 (which is the version on c.h.o) does read darcs 2 repositories as support for that feature exists in all darcs 2.x clients. And I personally think that c.h.o should be upgraded to darcs 2.4.4, but that issue is orthogonal to the issue of getting maintainers to upgrade to hashed format repos. Darcs currently has 3 options for repo formats: * old fashioned * darcs 1 hashed * darcs 2 hashed The old fashioned format will eventually be removed as it's not as robust or safe as the hashed variants. The big difference between darcs 1 hashed and darcs 2 hashed is how patches behave when commuted. The darcs 2 hashed variant is a refinement that better handles some corner cases that result from conflicts. Something like 90% of the code in darcs is shared between darcs 1 hashed and darcs 2 hashed. The hashed formats are more robust because: * the hashes guard against accidental modification of patches that are stored on disk * the hashes guard against a buggy darcs client that misapplies patches (the hashes would be off, git has similar safe guards) * the hashed formats have better atomicity and hence better transactional properties If you try the hashed format and find it unpleasant for any reason it's something to report as a bug. We really want (and need) people to switch to hashed, so if it's not good enough we need to know why so we can fix it. Jason ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
