haskellPackages.callCabal2nix has no way to specify cabal2nix flags

[Taneb]

Issue description

Often when developing Haskell with nix, we want to specify cabal flags. There's currently haskell.lib.(en/dis)ableCabalFlag, but this can't change the build inputs, which causes frustrating breakages. The solution to this is to pass the flag to cabal2nix. haskellSrc2nix already has the extraCabal2nixOptions parameter, which does exactly this, but there's no way to prapogate this from callCabal2nix.

[cocreature]

There are already two PRs that would fix this, so it seems like it’s just a question of merging one of these: #44424 and #42658

[Taneb]

Closed by #44424

[steve-chavez]

Just find out the way to do this:

pkgs.haskell.lib.enableCabalFlag (pkgs.haskellPackages.callCabal2nix name src {}) "myflag";