Cannot get cabal-fmt to build with hackage-tool

[ocharles]

If I do:

    self.haskell-nix.hackage-tool {
      compiler-nix-name = "ghc8101";
      name = "cabal-fmt";
      version = "0.1.4";
    }

I get:

❯ nix-build -E '(import ./nix/pkgs {}).cabal-fmt'
warning: unknown setting 'experimental-features'
trace: No index state specified for cabal-fmt, using the latest index state that we know about (2021-01-19T00:00:00Z)!
warning: unknown setting 'experimental-features'
building '/nix/store/4v7mg6xvvncw8lpw3rmg8jr2jrhfkha6-cabal-fmt-plan-to-nix-pkgs.drv'...
Using index-state 2021-01-19T00:00:00Z
Warning: The package list for 'hackage.haskell.org-at-2021-01-19T000000Z' is
18646 days old.
Run 'cabal update' to get the latest list of available packages.
Warning: Requested index-state2021-01-19T00:00:00Z is newer than
'hackage.haskell.org-at-2021-01-19T000000Z'! Falling back to older state
(2021-01-18T22:55:30Z).
Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] next goal: Cabal (user goal)
[__0] rejecting: Cabal-3.2.1.0, Cabal-3.2.0.0/installed-3.2.0.0,
Cabal-3.2.0.0, Cabal-3.0.2.0, Cabal-3.0.1.0, Cabal-3.0.0.0 (constraint from
user target requires ==2.5.0.0)
[__0] trying: Cabal-2.5.0.0
[__1] rejecting: Cabal:!test (constraint from config file, command line flag,
or user target requires opposite flag selection)
[__1] trying: Cabal:*test
[__2] next goal: optparse-applicative (dependency of Cabal *test)
[__2] rejecting: optparse-applicative-0.16.1.0, optparse-applicative-0.16.0.0,
optparse-applicative-0.15.1.0, optparse-applicative-0.15.0.0 (conflict: Cabal
*test => optparse-applicative>=0.13.2.0 && <0.15)
[__2] trying: optparse-applicative-0.14.3.0
[__3] next goal: base (dependency of Cabal)
[__3] rejecting: base-4.14.0.0/installed-4.14.0.0 (conflict:
optparse-applicative => base>=4 && <4.13)
[__3] skipping: base-4.14.1.0, base-4.14.0.0, base-4.13.0.0 (has the same
characteristics that caused the previous version to fail: excluded by
constraint '>=4 && <4.13' from 'optparse-applicative')
[__3] rejecting: base-4.12.0.0, base-4.11.1.0, base-4.11.0.0, base-4.10.1.0,
base-4.10.0.0, base-4.9.1.0, base-4.9.0.0, base-4.8.2.0, base-4.8.1.0,
base-4.8.0.0, base-4.7.0.2, base-4.7.0.1, base-4.7.0.0, base-4.6.0.1,
base-4.6.0.0, base-4.5.1.0, base-4.5.0.0, base-4.4.1.0, base-4.4.0.0,
base-4.3.1.0, base-4.3.0.0, base-4.2.0.2, base-4.2.0.1, base-4.2.0.0,
base-4.1.0.0, base-4.0.0.0, base-3.0.3.2, base-3.0.3.1 (constraint from
non-upgradeable package requires installed instance)
[__3] fail (backjumping, conflict set: Cabal, base, optparse-applicative)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: Cabal, optparse-applicative,
Cabal:test, base
Try running with --minimize-conflict-set to improve the error message.

I'm not really sure what's going on. I tried adding

      modules = [ { reinstallableLibGhc = true; } ];

But I get the same.

[ocharles]

With

      configureArgs = "--disable-tests";

❯ nix-build -E '(import ./nix/pkgs {}).cabal-fmt'
warning: unknown setting 'experimental-features'
trace: No index state specified for cabal-fmt, using the latest index state that we know about (2021-01-19T00:00:00Z)!
warning: unknown setting 'experimental-features'
building '/nix/store/8vr7aj6s3gj85klr3ci194m0rszb71pr-cabal-fmt-plan-to-nix-pkgs.drv'...
Using index-state 2021-01-19T00:00:00Z
Warning: The package list for 'hackage.haskell.org-at-2021-01-19T000000Z' is
18646 days old.
Run 'cabal update' to get the latest list of available packages.
Warning: Requested index-state2021-01-19T00:00:00Z is newer than
'hackage.haskell.org-at-2021-01-19T000000Z'! Falling back to older state
(2021-01-18T22:55:30Z).
Resolving dependencies...
cabal: Could not resolve dependencies:
[__0] next goal: cabal-fmt (user goal)
[__0] rejecting: cabal-fmt-0.1.5.1, cabal-fmt-0.1.5, cabal-fmt-0.1.4,
cabal-fmt-0.1.3, cabal-fmt-0.1.2, cabal-fmt-0.1.1, cabal-fmt-0.1 (constraint
from user target requires ==0)
[__0] rejecting: cabal-fmt-0 (constraint from user target requires ==0.1.4)
[__0] fail (backjumping, conflict set: cabal-fmt)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: cabal-fmt

[michaelpj]

That's very weird. The log output makes no sense to me: the first thing we see is it trying to solve for Cabal and saying it has a user goal of Cabal==2.5.0.0, whereas cabal-fmt says Cabal >=3.2.0.0. I have no idea what's going on there.

[michaelpj]

[__0] rejecting: cabal-fmt-0.1.5.1, cabal-fmt-0.1.5, cabal-fmt-0.1.4,
cabal-fmt-0.1.3, cabal-fmt-0.1.2, cabal-fmt-0.1.1, cabal-fmt-0.1 (constraint
from user target requires ==0)

what on earth???

[ocharles]

Yea, very puzzling! I'm going to try adding a cabal.project...

[ocharles]

Bingo! It's the lack of a cabal.project that blows this all up. The following works:

    self.haskell-nix.hackage-tool {
      compiler-nix-name = "ghc8101";
      name = "cabal-fmt";
      version = "0.1.4";
      cabalProject = ''
        packages: .
      '';
    };

[brendanhay]

I'm glad I came across this by chance - I've had this issue with cabal-fmt for over a year, thanks @ocharles!

[michaelpj]

Hm, I think this should still be open: you shouldn't need the cabal.project, something is rather odd.

[TerrorJack]

Seems that the cabalProject hack can be removed given the latest haskell.nix revision, just fyi.

[ocharles]

I wonder what fixed it!

[hamishmack]

Checked this and it seems ok now:

nix-build -E '((import ./. {}).pkgs-unstable.haskell-nix.tool "ghc8107" "cabal-fmt" {})'