Re: [Haskell-cafe] I do not want to be a bitch, but ghc-6.8.3 and haskell binary policy are really horrible.

Thank you for your reply. So the main information I got is that cabal is not safe. And my problems are all related to cabal, I think, dependency, ABI version.... I hope everything could be better soon. At least, tools should not block the way of producing. Thomas Schilling wrote:

2008/10/14 Magicloud :

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Sorry, let me say it this way: 1. Ghc cannot be bootstrap-installed. And the ghc-6.8.3 binary from official website also cannot run in my box, some kind of overflow error. So I have to look for help, a few hours later, I found 6.4.2 (I am not sure) which runs well in my box, and install ghc-6.8.3 indirectly.

Hm, the only issue with binary installers I had were old versions of some libraries which could be resolved by adding a few symlinks. What system are you on?

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2. After `cabal update && cabal upgrade`, ghc-6.8.3 cannot be built.

Which version of cabal-install ( cabal --version ) are you using? Note that 'cabal upgrade' is not guaranteed to work since libraries on hackage don't always specify their dependencies correctly and older versions of cabal-install might have some issues. There's an ongoing initiative to have a set of more controlled packages, the Haskell Platform. It should soon has its first release.

That said, you shouldn't need to upgrade anything if you want to build ghc 6.8.3 with 6.4.2. Also, what version of ghc does you distribution provide?

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Lib Network.URI cannot be compiled because: Network/CGI/Protocol.hs:41:0: Failed to load interface for `Network.URI': Perhaps you haven't installed the profiling libraries for package network-2.2.0.0? Use -v to see a list of the files searched for. I remove this SUBDIRS from the Makefile, luckly, it works. A few more hours lost in my life. 3. When I `ghc -v`, there are lots of "hiding package xxx to avoid conflict with later version yyy", do I have a way to remove these hiding packages? And "package xx will be ignored due to missing or recursive dependencies: yy", what does this mean? If it is ignored, my program using it compiled and run well. If the dependencies are not right, how can I fix it? I installed this by cabal. It reports nothing wrong and cannot check if all packages dependencies are OK. 4. When `cabal upgrade`, I do not think it knows what it is doing. There were many times that I cannot upgrade because I should manually reinstall some packages to make it work (Some guy say that this is because ghc cannot know the difference between two lib files with the same name). And, cabal does not upgrade all packages, I do not know why.

The issue is binary compatibility. At the moment, GHC cannot make sure that a library compiled with an older GHC can work with a newer GHC. GHC does many cross-module optimisations, and its runtime system changes occasionally, so it is very pessimistic in that regard. This becomes an issue for packages that GHC has been build with itself (like base, process, array), since these cannot be upgraded without recompiling GHC (hence requiring recompiling every other package). Older versions of cabal-install could not deal with this correctly. So in short, "cabal upgrade" (without arguments) is probably not very safe, atm.

There are ongoing efforts to provide more ABI compatibility guarantees, but that requires solving of some difficult issues, so we're not there yet.

There are certainly some things that could be improved. For example GHC 6.10 won't let you unregister a package that other packages depend on and it keeps checksums of the ABI which may be used by future versions of Cabal/cabal-install.

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5. Sometimes when I upgrade some libraries, ghc failed to compile, because ld failed to find the new libraries. (Which proves that ghc cannot deal with binary files right). I need to recompile this, and recompile that, MAYBE it would be resolved.

Without further details I can just guess, but I think this is related to the problems with binary compatibility above.

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Everyday, I spend a few hours on compiling. Does it really need to be so terrible? With erlang or ruby, I never spend more time debugging as haskell's feature says but less time on how to run my code.

Many projects can just be loaded via ghci which is a lot faster. Just cd to the toplevel source directory, type :l ModuleName. Then edit the source code, and type :r to reload the current module.

With many of these smaller issues you can often find quick help on Haskell's IRC channel #haskell or #ghc if you have problems specific to GHC (although asking at #haskell will often give you an answer more quickly, so ask there first anyway)

HTH,

Thomas

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Thomas Schilling wrote:

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It would be helpful if you could describe exactly what you did so we can work on improving the issue in the long term (and help you fix it in the short term).

2008/10/14 Magicloud :

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1. I cannot install ghc-6.8.3 in my box until I found the old runable binary. 2. After I installed cabal, and upgraded, ghc-6.8.3 cannot rebuild itself. Because its libraries are conflict with the ones upgraded by cabal. 3. Sometimes, ghc just ignore some libs, because it does not meet its dependencies. Well, ghc does not even tell me. It knows what I want? 4. I use cabal, thinking it would make dependencies installation easier for me. Well it does not, once an error happened, nothing would work since. I cannot even remove the broken lib. 5. No more needed. The above ones, which are important enough to drive me crazy. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe