Difference between revisions of "Upgrading packages/Updating to GHC 6.10"
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− | == |
+ | == Typical breakages with GHC 6.10 == |
+ | [http://article.gmane.org/gmane.comp.lang.haskell.glasgow.user/15430 54 new packages] break with the current GHC 6.10 release candidate. |
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− | * Exceptions |
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+ | |||
+ | The primary reasons are: |
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+ | |||
+ | * Changes to Arrow class definition |
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+ | * Changes to Map monadic types |
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+ | * Cabal changes |
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+ | * Changes to ghc-api |
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+ | * Changes to when 'forall' is parsed |
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+ | * GHC.Prim was moved, |
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+ | * Changes to -fvia-C and headers? |
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+ | * GADT changes, |
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+ | * pragma warnings tightened |
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+ | * Integer constructors have moved |
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+ | * New warnings and used -Werror |
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+ | |||
+ | Each of these has a standard way to solve the problem. Techniques should be attached here. |
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== Backwards compatibility == |
== Backwards compatibility == |
Revision as of 17:14, 11 October 2008
A list of things that need updating when porting packages to newer library/cabal versions.
If you maintain a Haskell package this is for you. For older versions of this document:
Updating to GHC 6.10 and Cabal 1.6
When upgrading to GHC 6.10, any of your packages that worked against the base-3 library will continue to work. GHC 6.10 provides both the old base-3 library and the new base-4.
To ensure your old code continues to work, you can have the code compile and link against base-3, and then, over time, migrate code to the base-4 series.
Adding base-3 constraints
How to do this depends on how you build your Haskell code. We'll start with the most simplistic build mechanisms. cabal-install, the most sophisticated tool, will sort this all out for you anyway, so things should change.
ghc --make
Force use of package base-3 when using --make,
ghc --make --package base-3.0.3.0
runhaskell
If you build your packages with the 'runhaskell Setup.hs configure' method, then you can force the use of base-3,
--constraint="base<4"
cabal-install
It is worth upgrading cabal-install immediately (maybe before installing GHC). This way you can use the smart dependency solver to work out what to install for you.
* install HTTP from hackage * install zlib from hackage
Then build cabal-install.
You can also override the dependencies when using the 'cabal' binary, with
--constraint="base<4"
Typical breakages with GHC 6.10
54 new packages break with the current GHC 6.10 release candidate.
The primary reasons are:
- Changes to Arrow class definition
- Changes to Map monadic types
- Cabal changes
- Changes to ghc-api
- Changes to when 'forall' is parsed
- GHC.Prim was moved,
- Changes to -fvia-C and headers?
- GADT changes,
- pragma warnings tightened
- Integer constructors have moved
- New warnings and used -Werror
Each of these has a standard way to solve the problem. Techniques should be attached here.
Backwards compatibility
The new, suggested Cabal version range syntax,
build-depends: base-3.*
is not backwards compatible with older versions of Cabal. Users will need to upgrade to the newer Cabal to build packages that start using this syntax.