How to tell haskell.nix to ignore versions for packages that come with ghc

[domenkozar]

Since Cabal 3.0.1.0 is not on hackage yet, I get:

error: attribute '3.0.1.0' missing, at /nix/store/gbihrrlh3m6d2ihms7lr2fkf0x9wj7r0-stackage-snapshot-source/nightly-2020-02-03.nix:1623:28

I'd like to tell haskell.nix to just use the one from ghc.

[angerman]

@domenkozar you can set a module like:

{
                nonReinstallablePkgs = [ "Cabal" "array" "base" "binary" "bytestring" "containers" "deepseq"
                                         "directory" "filepath" "ghc" "ghc-boot" "ghc-boot-th" "ghc-compact"
                                         "ghc-heap" "ghc-prim" "ghci" "haskeline" "hpc" "integer-gmp"
                                         "libiserv" "mtl" "parsec" "pretty" "process" "rts" "stm"
                                         "template-haskell" "terminfo" "text" "time" "transformers" "unix"
                                         "xhtml"
                                         ];
}

which should make haskell.nix pick those libraries from the ones in the pkg-db that ghc ships.

[domenkozar]

Still the same error.

[angerman]

Just adding this info from IRC (irc.freenode.net#haskell.nix):

<domenkozar[m]> oh btw, you can just play with it yourself
<domenkozar[m]> https://github.com/hercules-ci/ghcide-nix
<domenkozar[m]> ghc-8.8 branch

[dhess]

We're now hitting this, as well, with cabalProject. Trying the nonReinstallablePkgs trick didn't work for us, either.

[domenkozar]

Cabal versions are now on hackage.

[dhess]

So the next haskell.nix auto-update should see them, right?

[domenkozar]

It already does have them :)

[dhess]

Indeed!

I had to add this stanza to my GHC 8.8.3 cabalProject:

 pkg-def-extras = [
    (hackage: {
      alex = hackage.alex."3.2.5".revisions.default;
    })
  ];

but at least it's building now!

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[hamishmack]

This is still potentially a problem for the packages still in nonReinstallablePks by default, but now that reinstallableLibGhc is the default that list is much smaller.

haskell.nix/modules/component-driver.nix

Lines 56 to 65 in e94f30c

	config.nonReinstallablePkgs =
	[ "rts" "ghc-prim" "integer-gmp" "integer-simple" "base"
	"deepseq" "array" "ghc-boot-th" "pretty" "template-haskell"
	# ghcjs custom packages
	"ghcjs-prim" "ghcjs-th"
	]
	# TODO make this unconditional
	++ lib.optionals (
	__elem config.compiler.nix-name ["ghc901" "ghc902" "ghc921" "ghc922" "ghc923" "ghc924"]) [
	"ghc-bignum" ]

Making the remaining packages reinstallable would still be nice, but I think we can track that work in issues like #1254