bug#53162: ’guix shell ghc@8.4’ downloads ghc@8.10

[Ludovic Courtès]

Hi,

zimoun <zimon.toutoune@gmail.com> skribis:

>>From the profile.drv, the culprit is identified:
> /gnu/store/…-ghc-package-cache.drv,
>
> Derive
> ([("out","/gnu/store/mcmwdg13f5rc9vdklgbmsn6h84bgdp3q-ghc-package-cache","","")]
>  ,[("/gnu/store/8m7vppxy4l824yk4036iisk2zy7qzgcx-ghc-8.4.4.drv",["out"])
>    ,("/gnu/store/bc5cm1g1b884nvgiysq8x0i0wxplkqhl-ghc-8.10.7.drv",["out"])
>    ,("/gnu/store/m0nbbk3vgl637ibrz7z72r5v0dkswpi2-guile-3.0.7.drv",["out"])
>    
> ,("/gnu/store/qcksap17gs36gpnjj3by4d7r7yxfq405-module-import-compiled.drv",["out"])]
>  
> ,["/gnu/store/45dpf18lzvzs6sbmihifw6ch9p6y20yr-ghc-package-cache-builder","/gnu/store/4j2xcm5s0hvmpjm8fdbmb02ipvr6wyxn-module-import"]
>  
> ,"x86_64-linux","/gnu/store/fidl08nms5v63lkqv627zibxpd85zxqb-guile-3.0.7/bin/guile",["--no-auto-compile","-L","/gnu/store/4j2xcm5s0hvmpjm8fdbmb02ipvr6wyxn-module-import","-C","/gnu/store/n7687sw6nkrhpjkdgysgz7baihzipgl0-module-import-compiled","/gnu/store/45dpf18lzvzs6sbmihifw6ch9p6y20yr-ghc-package-cache-builder"]
>  ,[("allowSubstitutes","0")
>    ,("guix properties","((type . profile-hook) (hook . ghc-package-cache))")
>    ,("out","/gnu/store/mcmwdg13f5rc9vdklgbmsn6h84bgdp3q-ghc-package-cache")
>    ,("preferLocalBuild","1")])
>
>
>
>>From my perspective, it is a bug from (guix profiles)
> ’ghc-package-cache-file’ which always includes ’ghc’, currently pointing
> to ghc@8.10.
>
>   (define ghc                                     ;lazy reference
>     (module-ref (resolve-interface '(gnu packages haskell)) 'ghc))
>
> Well, the fix is not jumping to my eyes.  If someone has an idea to
> conditionally remove this reference to ’ghc’?

Is it a problem that the latest GHC is used to build the package cache?
(Apart from being surprising and suboptimal.)

Some profile hooks, such as ‘gdk-pixbuf-loaders-cache-file’, use the
package available in the closure (gdk-pixbuf in this case) rather than
the latest version.  It’s a bit of a hack, but if required, we could do
that.

Ludo’.