June 2009 - cabal-devel

patch applied (cabal-branches/cabal-install-0.6): Only report preferred new versions of cabal-install are available
by Duncan Coutts 05 Jun '09

05 Jun '09

Thu Jun 4 10:57:26 PDT 2009 Duncan Coutts <duncan(a)haskell.org> * Only report preferred new versions of cabal-install are available That is, use the "preferred-versions" mechanism when deciding whether there is a new version available. This would allow us to upload a new version without everyone immediately being told to get it and try it out. M ./Distribution/Client/Update.hs -12 +21 View patch online: http://darcs.haskell.org/cabal-branches/cabal-install-0.6/_darcs/patches/20…

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[Hackage] #549: The reason for an upload error is not reported
by Hackage 04 Jun '09

04 Jun '09

#549: The reason for an upload error is not reported ---------------------------------+------------------------------------------ Reporter: guest | Owner: Type: defect | Status: new Priority: normal | Milestone: Component: cabal-install tool | Version: 1.6.0.2 Severity: normal | Keywords: Difficulty: unknown | Ghcversion: Platform: | ---------------------------------+------------------------------------------ I don't have a paste to hand, but when `cabal upload` fails due to an error from the server, the error message is not displayed unless you also increase the verbosity (`-v3` worked for me). See also #338. Apparently this also affects download, not only upload. -- Ticket URL: <http://hackage.haskell.org/trac/hackage/ticket/549> Hackage <http://haskell.org/cabal/> Hackage: Cabal and related projects

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patch applied (cabal-install): Fix use of deprecated version constructors
by Duncan Coutts 04 Jun '09

04 Jun '09

Thu Jun 4 11:05:00 PDT 2009 Duncan Coutts <duncan(a)haskell.org> * Fix use of deprecated version constructors M ./Distribution/Client/Update.hs -2 +2 View patch online: http://darcs.haskell.org/cabal-install/_darcs/patches/20090604180500-adfee-…

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patch applied (cabal-install): Only report preferred new versions of cabal-install are available
by Duncan Coutts 04 Jun '09

04 Jun '09

Thu Jun 4 10:57:26 PDT 2009 Duncan Coutts <duncan(a)haskell.org> * Only report preferred new versions of cabal-install are available That is, use the "preferred-versions" mechanism when deciding whether there is a new version available. This would allow us to upload a new version without everyone immediately being told to get it and try it out. M ./Distribution/Client/Update.hs -12 +21 View patch online: http://darcs.haskell.org/cabal-install/_darcs/patches/20090604175726-adfee-…

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patch applied (cabal-install): Make cabal upload/check print out the error messages reported by the server
by Duncan Coutts 04 Jun '09

04 Jun '09

Thu Jun 4 05:48:36 PDT 2009 Duncan Coutts <duncan(a)haskell.org> * Make cabal upload/check print out the error messages reported by the server The code to do it was already there but we were checking for the mime type text/plain using just (==) when in fact the server reports text/plain; charset="ISO-8859-1" so we have to parse the field a bit better (still a bit of a hack). M ./Distribution/Client/Upload.hs -4 +6 View patch online: http://darcs.haskell.org/cabal-install/_darcs/patches/20090604124836-adfee-…

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Re: Notice for package authors
by Duncan Coutts 04 Jun '09

04 Jun '09

On Thu, 2009-06-04 at 09:13 +0000, kahl(a)cas.mcmaster.ca wrote: > [Not replying to haskell-cafe since not subscribed.] > > Duncan wrote: > > > > There is no way for the tools to discover if you mean base 3 or 4 and > > yet most packages break when we pick the wrong one. You must specify an > > upper bound so that your package does not break when the next major > > version of the base library is released. > > > > For example, if you've tested with base 3 and 4 then use: > > > > build-depends: base >= 3 && < 5 > > Then ``build-depends'' is a misnomer because most packages will most likely > not DEPEND on the fact that the used base package has version less than 5. It depends on how much base 5 changes from 4 as to the likelihood of the package breaking. Looking back at the days of base 2, I think retrospectively we can reasonably say that all the packages that used "build-depends: base >=2" really did "DEPEND" on the fact that the used base package has version less than 3. The transition to base 3 was very disruptive, only the most trivial programs did not break. It's true that it's pessimistic and based on future unknowns. Other people have also suggested that it should not be "depends" but something else to say that it's a speculative upper bound rather than a known one based on testing. > This misnomer is one major source of my uneasiness with cabal. The upper bound bits specifically or generally using version ranges? Version ranges do only make sense when you know the versioning policy of the package you're depending on, so that you know how changes in future versions of the package will be reflected in version number changes. > I would like to propose ``tested-with'' as a better name, > and would like to see a way for users to easily test with a version > I did not have avaliable, and report that back (perhaps to hackage). Certainly speculatively trying with later versions and reporting is a useful thing. Doing it via hackage build clients and emailing authors would be nice. > Of ocurse, I can, for example, honestly only write > > tested-with: base `elem` [2.1.1, 3.0.1.0, 3.0.3.1, 4.1.0.0] > > because those are the versions I happen to have lying around, > and you probably would like to allow building with Given that you know the versions that worked and you know that the package in question is following the PVP (otherwise none of this makes sense) then you can derive the upper bounds you're interested in. > But in general there is no guarantee that a give package actually > implements that, or does hackage test for compliance with the > version convention? Right, it only makes sense if you know the versioning policy of the package. In particular we know base follows the PVP. An idea is to let packages opt-in to following a named version policy (eg the PVP). > Yet another problem is that if I write > > tested-with: > pkg1 == v1_1 || == v1_2 > ... > pkg9 == v9_1 || == v9_2 > > , I probably won't have tested all 2^9 combinations... Yes, we have to assume some kind of independence. Clearly version numbers are an approximation of precise type (and semantic) interfaces. It's not a total solution but should help significantly reduce the number of packages that needlessly break in confusing ways when end-users upgrade things. We're certainly not trying to suppress ideas or work on better, more complete solutions. In the mean time we're trying to reduce the expected pain of breakage at major transitions. Duncan

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Notice for package authors
by Duncan Coutts 03 Jun '09

03 Jun '09

Package authors, We are about to add an additional quality check in the Hackage upload process that will affect many packages. Hackage will require an upper bound on the version of the base package and reject packages that omit it. Lots of packages currently specify: build-depends: base or build-depends: base >= 3 This is bad. There is no way for the tools to discover if you mean base 3 or 4 and yet most packages break when we pick the wrong one. You must specify an upper bound so that your package does not break when the next major version of the base library is released. For example, if you've tested with base 3 and 4 then use: build-depends: base >= 3 && < 5 Or if it needs version 4 then use: build-depends: base == 4.* Background ---------- When base 4 was released with ghc-6.10.x the vast majority of packages would have broken were it not for a compatibility shim that we added to the cabal-install tool. It defaulted to picking base 3 when the version constraints did not otherwise specify the use of base 4. The same trick will not work when base 5 is released because it will likely not be possible to continue to ship base 3. It is also important that we start to move towards making the majority of packages compatible with base 4. cabal-install changes --------------------- We will shortly release a minor update to cabal-install to change the way it picks between base 3 and 4. Currently if it has the choice it picks version 3. However that is not optimal for cases like: build-depends: base >= 3 && < 5 where it is clear that it is supposed to work with both. In this case we should not be pessimistic in going with the old base 3 and should instead pick base 4. More precisely, we will only apply the compatibility shim when the version is unbounded above. When it is bounded above, as Hackage will soon require, the normal preference to use the latest version applies. If you'd like to help us check this feature is working properly then grab the latest darcs version of cabal-install (which needs the latest darcs version the Cabal lib). See also http://hackage.haskell.org/trac/hackage/ticket/485 Duncan

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checking upper bounds on base
by Duncan Coutts 03 Jun '09

03 Jun '09

Hi Ross, I'd like to get Hackage using the new check for base being bounded above. I think it'll make a big difference when it comes to future ghc/base upgrades. The last one was papered over by cabal-install defaulting to base 3 when the package author did not specify otherwise. That will not work forever. You mentioned in the ticket that we need to have base strictly following the PVP. That's true of course. I'm assured by the GHC hackers that they're committed to the PVP. The reason for bumping 4.0 -> 4.1 is being looked at but their first guess is that it was the change in GHC's finaliser semantics (which did indeed break a couple programs). For the practical issues: I'll can send announcement to the haskell (+cafe) mailing list explaining what people have to do and the rationale. There have been a number of changes in the Cabal lib recently, it may be that you prefer to just pull the checking patch for the hackage-scripts rebuild, rather than everything. OTOH, I don't expect any problems from pulling everything as the changes have been mostly in the build system side of things. What do you think? Is this a sane plan? Duncan

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patch applied (cabal-install): Require latest Cabal lib version
by Duncan Coutts 03 Jun '09

03 Jun '09

Wed Jun 3 03:23:12 PDT 2009 Duncan Coutts <duncan(a)haskell.org> * Require latest Cabal lib version M ./cabal-install.cabal -1 +1 View patch online: http://darcs.haskell.org/cabal-install/_darcs/patches/20090603102312-adfee-…

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patch applied (cabal-install): Improve formatting of cabal check output
by Duncan Coutts 03 Jun '09

03 Jun '09

Wed Jun 3 03:22:54 PDT 2009 Duncan Coutts <duncan(a)haskell.org> * Improve formatting of cabal check output M ./Distribution/Client/Check.hs -9 +9 View patch online: http://darcs.haskell.org/cabal-install/_darcs/patches/20090603102254-adfee-…

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