CODEWITHSUNDEEP
haskellpackagecabal
Code-Apprentice
Code-Apprentice

Reputation: 83567

Compile Haskell program with third-party dependencies

I am trying to jump into some Haskell again after being away for a while. One piece of code I wrote ages ago inclues import qualified Data.MultiMap as MultiMap. Since Data.MultipMap is in the containers package, I get errors when I just run ghc program.hs. I've attempted to write a project.cabal file based on How to make a Haskell cabal project with library+executables that still run with runhaskell/ghci?. My latest attempt is

name: project
version: 1.0
executable project
    main-is: project.hs
    build-dependencies:
        base >= 4 && <= 5
      , containers

Now when I do cabal build project, I get

Resolving dependencies...
cabal.exe: Could not resolve dependencies:
[__0] trying: project-1.0 (user goal)
[__1] next goal: project:setup.Cabal (dependency of project)
[__1] rejecting: project:setup.Cabal-3.4.0.0/installed-3.4.0.0 (conflict:
project => project:setup.Cabal>=1.0 && <1.25)
[__1] skipping: project:setup.Cabal-3.4.0.0, project:setup.Cabal-3.2.1.0,
project:setup.Cabal-3.2.0.0, project:setup.Cabal-3.0.2.0,
project:setup.Cabal-3.0.1.0, project:setup.Cabal-3.0.0.0,
project:setup.Cabal-2.4.1.0, project:setup.Cabal-2.4.0.1,
project:setup.Cabal-2.4.0.0, project:setup.Cabal-2.2.0.1,
project:setup.Cabal-2.2.0.0, project:setup.Cabal-2.0.1.1,
project:setup.Cabal-2.0.1.0, project:setup.Cabal-2.0.0.2 (has the same
characteristics that caused the previous version to fail: excluded by
constraint '>=1.0 && <1.25' from 'project')
[__1] rejecting: project:setup.Cabal-1.24.2.0, project:setup.Cabal-1.24.0.0,
project:setup.Cabal-1.22.8.0, project:setup.Cabal-1.22.7.0,
project:setup.Cabal-1.22.6.0, project:setup.Cabal-1.22.5.0,
project:setup.Cabal-1.22.4.0, project:setup.Cabal-1.22.3.0,
project:setup.Cabal-1.22.2.0, project:setup.Cabal-1.22.1.1,
project:setup.Cabal-1.22.1.0, project:setup.Cabal-1.22.0.0,
project:setup.Cabal-1.20.0.4, project:setup.Cabal-1.20.0.3,
project:setup.Cabal-1.20.0.2, project:setup.Cabal-1.20.0.1,
project:setup.Cabal-1.20.0.0, project:setup.Cabal-1.18.1.7,
project:setup.Cabal-1.18.1.6, project:setup.Cabal-1.18.1.5,
project:setup.Cabal-1.18.1.4, project:setup.Cabal-1.18.1.3,
project:setup.Cabal-1.18.1.2, project:setup.Cabal-1.18.1.1,
project:setup.Cabal-1.18.1, project:setup.Cabal-1.18.0,
project:setup.Cabal-1.16.0.3, project:setup.Cabal-1.16.0.2,
project:setup.Cabal-1.16.0.1, project:setup.Cabal-1.16.0,
project:setup.Cabal-1.14.0, project:setup.Cabal-1.12.0,
project:setup.Cabal-1.10.2.0, project:setup.Cabal-1.10.1.0,
project:setup.Cabal-1.10.0.0, project:setup.Cabal-1.8.0.6,
project:setup.Cabal-1.8.0.4, project:setup.Cabal-1.8.0.2,
project:setup.Cabal-1.6.0.3, project:setup.Cabal-1.6.0.2,
project:setup.Cabal-1.6.0.1, project:setup.Cabal-1.4.0.2,
project:setup.Cabal-1.4.0.1, project:setup.Cabal-1.4.0.0,
project:setup.Cabal-1.2.4.0, project:setup.Cabal-1.2.3.0,
project:setup.Cabal-1.2.2.0, project:setup.Cabal-1.2.1,
project:setup.Cabal-1.1.6, project:setup.Cabal-1.24.1.0 (constraint from
minimum version of Cabal used by Setup.hs requires >=3.4)
[__1] fail (backjumping, conflict set: project, project:setup.Cabal)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: project:setup.Cabal, project

What am I missing to get this to work? What should I do to compile my Haskell program?

Upvotes: 0

Views: 384

Answers (1)

duplode
duplode

Reputation: 34398

Change your project.cabal to:

cabal-version: 3.4
name: project
version: 1.0
executable project
    main-is: project.hs
    build-depends:
        base >= 4 && <= 5
      , multimap

cabal-version: 3.4 picks the latest version of the Cabal package format, which should be fine to use given that you are using Cabal 3.4 already. Left unspecified, cabal-version defaults to a very old version (as in recent versions the field is mandatory), which makes the build-type field default to Custom rather than Simple. That, in turn, leads to the error you got, as described in cabal issue #5278. In addition, I have changed build-dependencies to build-depends, and containers to multimap (as the latter package is the one that provides Data.MultiMap).

Upvotes: 2

Related Questions