lts-14.* snapshots fails with "'libiserv' missing"

[madjar]

Hi there!

After upgrading to the recent overlay changes, it appears my stack project has stopped working. The issue seems to boil down to the following:

Inside of nix repl (or, anywhere you would evaluate nix code), run:
(import <nixpkgs> (import (builtins.fetchTarball https://github.com/input-output-hk/haskell.nix/archive/master.tar.gz))).haskell-nix.snapshots."lts-14.11"

It fails with attribute 'libiserv' missing, at /nix/store/xxidvhr3q8z5g4r85mp92dvfw4rxiy9h-stackage-snapshot-source/lts-14.11.nix:1388:32

This is an issue for all lts-14* snapshots, but not 13. It seems that all lts-14.*.nix files in stackage.nix refer to libiserv, which is not actually in hackage (it seems to be part of ghc, if I understand correctly).

[angerman]

@madjar thanks for the report. And yes libiserv is something that comes with ghc (recent versions), and is provided by the ghc-packages overlay. I wonder why this isn't picked up for lts-14.11 though.

[blitz]

@angerman We are hitting this issue as well. What component actually needs fixing here and is there a way to help?

[fiadliel]

In case it helps someone (temporarily) to get past this issue, I forked stackage.nix to remove the "libiserv" attribute, following https://github.com/input-output-hk/haskell.nix/blob/master/docs/user-guide.md#overriding-the-hackage-version

[blitz]

@hamishmack @angerman Ping. Do you have any idea how to fix this without resorting to overriding?

[purefn]

I tried updating to the latest commit b8af990 and am still encountering this issue. :(

[roberth]

Still happens on f2fffb6

[hamishmack]

Ah I see. I only fixed this for the haskell-nix.snapshots. So things like:

nix-build -E '(import ./nixpkgs (import ./.)).haskell-nix.snapshots."lts-14.13".hpack.components.exes.hpack'

now work.