Add a projectArgs CLI argument to hix run

[demaledetti]

hix run could be even more useful if it allowed tweaking the build on the fly by passing custom arguments to callCabalProjectToNix.

For example latest hlint wants latest ghc:

$ nix run github:input-output-hk/haskell.nix#hix -- run github:ndmitchell/hlint#hlint:exe:hlint -- --version 2>&1 | tail -n 20

       error: builder for '/nix/store/kaywxgj98har99969q8hjrzgnj6b7997-haskell-project-plan-to-nix-pkgs.drv' failed with exit code 1;
       last 15 log lines:
       > Configuration is affected by the following files:
       > - cabal.project
       > Warning: The package list for 'hackage.haskell.org' is 20235 days old.
       > Run 'cabal update' to get the latest list of available packages.
       > Resolving dependencies...
       > Error: [Cabal-7107]
       > Could not resolve dependencies:
       > [__0] trying: hlint-3.10 (user goal)
       > [__1] trying: ghc-lib-parser-9.12.2.20250421 (dependency of hlint +/-ghc-lib)
       > [__2] next goal: base (dependency of hlint)
       > [__2] rejecting: base-4.18.3.0/installed-4.18.3.0 (conflict: ghc-lib-parser => base>=4.19 && <4.22)
       > [__2] rejecting: base; 4.21.0.0, 4.20.1.0, 4.20.0.1, 4.20.0.0, 4.19.2.0, 4.19.1.0, 4.19.0.0, 4.18.3.0, 4.18.2.1, 4.18.2.0, 4.18.1.0, 4.18.0.0, 4.17.2.1, 4.17.2.0, 4.17.1.0, 4.17.0.0, 4.16.4.0, 4.16.3.0, 4.16.2.0, 4.16.1.0, 4.16.0.0, 4.15.1.0, 4.15.0.0, 4.14.3.0, 4.14.2.0, 4.14.1.0, 4.14.0.0, 4.13.0.0, 4.12.0.0, 4.11.1.0, 4.11.0.0, 4.10.1.0, 4.10.0.0, 4.9.1.0, 4.9.0.0, 4.8.2.0, 4.8.1.0, 4.8.0.0, 4.7.0.2, 4.7.0.1, 4.7.0.0, 4.6.0.1, 4.6.0.0, 4.5.1.0, 4.5.0.0, 4.4.1.0, 4.4.0.0, 4.3.1.0, 4.3.0.0, 4.2.0.2, 4.2.0.1, 4.2.0.0, 4.1.0.0, 4.0.0.0, 3.0.3.2, 3.0.3.1 (constraint from non-reinstallable package requires installed instance)
       > [__2] fail (backjumping, conflict set: base, ghc-lib-parser, hlint)
       > After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: hlint, ghc-lib-parser, base
       >
       For full logs, run:
         nix log /nix/store/kaywxgj98har99969q8hjrzgnj6b7997-haskell-project-plan-to-nix-pkgs.drv

Works great if we pass compiler-nix-name:

$ nix run github:demaledetti/haskell.nix/hix-run-projectArgs#hix -- run github:ndmitchell/hlint#hlint:exe:hlint --projectArgs '{compiler-nix-name="ghc9122";}' -- --version 2> /dev/null
HLint v3.10, (C) Neil Mitchell 2006-2025

Another example of a useful tool failing to build with the defaults:

$ nix run github:input-output-hk/haskell.nix#hix -- run github:karknu/rws#rws:exe:rws 2>&1 | tail -n 22
       error: builder for '/nix/store/ykxwaw346zbmbdanviqbmiwjcffh13dn-haskell-project-plan-to-nix-pkgs.drv' failed with exit code 1;
       last 18 log lines:
       > Configuration is affected by the following files:
       > - cabal.project
       > Warning: The package list for 'hackage.haskell.org' is 20235 days old.
       > Run 'cabal update' to get the latest list of available packages.
       > Resolving dependencies...
       > Error: [Cabal-7107]
       > Could not resolve dependencies:
       > [__0] trying: rws-0.1.1.2 (user goal)
       > [__1] next goal: binary (dependency of rws)
       > [__1] rejecting: binary-0.8.9.1/installed-0.8.9.1 (conflict: rws => binary>=0.5 && <0.6)
       > [__1] skipping: binary; 0.8.9.3, 0.8.9.2, 0.8.9.1, 0.8.9.0, 0.8.8.0, 0.8.7.0, 0.8.6.0, 0.8.5.1, 0.8.5.0, 0.8.4.1, 0.8.4.0, 0.8.3.0, 0.8.2.1, 0.8.2.0, 0.8.1.0, 0.8.0.1, 0.8.0.0, 0.7.6.1, 0.7.6.0, 0.7.5.0, 0.7.4.0, 0.7.3.0, 0.7.2.3, 0.7.2.2, 0.7.2.1, 0.7.2.0, 0.7.1.0, 0.7.0.1, 0.7.0.0, 0.6.4.0, 0.6.3.0, 0.6.2.0, 0.6.1.0, 0.6.0.0 (has the same characteristics that caused the previous version to fail: excluded by constraint '>=0.5 && <0.6' from 'rws')
       > [__1] trying: binary-0.5.1.1
       > [__2] next goal: base (dependency of rws)
       > [__2] rejecting: base-4.18.3.0/installed-4.18.3.0 (conflict: binary +/-applicative-in-base +/-bytestring-in-base +/-split-base => base<2.2 || >=3 && <4.7)
       > [__2] rejecting: base; 4.21.0.0, 4.20.1.0, 4.20.0.1, 4.20.0.0, 4.19.2.0, 4.19.1.0, 4.19.0.0, 4.18.3.0, 4.18.2.1, 4.18.2.0, 4.18.1.0, 4.18.0.0, 4.17.2.1, 4.17.2.0, 4.17.1.0, 4.17.0.0, 4.16.4.0, 4.16.3.0, 4.16.2.0, 4.16.1.0, 4.16.0.0, 4.15.1.0, 4.15.0.0, 4.14.3.0, 4.14.2.0, 4.14.1.0, 4.14.0.0, 4.13.0.0, 4.12.0.0, 4.11.1.0, 4.11.0.0, 4.10.1.0, 4.10.0.0, 4.9.1.0, 4.9.0.0, 4.8.2.0, 4.8.1.0, 4.8.0.0, 4.7.0.2, 4.7.0.1, 4.7.0.0, 4.6.0.1, 4.6.0.0, 4.5.1.0, 4.5.0.0, 4.4.1.0, 4.4.0.0, 4.3.1.0, 4.3.0.0, 4.2.0.2, 4.2.0.1, 4.2.0.0, 4.1.0.0, 4.0.0.0, 3.0.3.2, 3.0.3.1 (constraint from non-reinstallable package requires installed instance)
       > [__2] fail (backjumping, conflict set: base, binary, rws)
       > After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: base, binary, rws
       >
       For full logs, run:
         nix log /nix/store/ykxwaw346zbmbdanviqbmiwjcffh13dn-haskell-project-plan-to-nix-pkgs.drv

configureArgs to the rescue to disable-tests and allow-newer:

$ nix run github:demaledetti/haskell.nix/hix-run-projectArgs#hix -- run github:karknu/rws#rws:exe:rws --projectArgs '{configureArgs = "--allow-newer=binary --disable-tests";}'  -- -i <(curl -s https://raw.githubusercontent.com/karknu/rws/refs/heads/master/samples/udp.pkt) -o /dev/stdout 2> /dev/null | nix run nixpkgs#tcpdump -- -enr -
reading from file -, link-type EN10MB (Ethernet), snapshot length 1600
01:00:00.000001 00:11:22:33:44:55 > 00:00:00:00:00:01, ethertype IPv4 (0x0800), length 50: 0.0.0.0.7 > 0.0.0.0.7: UDP, length 8

WARNING:

Before merging it's perhaps best to change the dependency on https://github.com/demaledetti/empty-set to be something under input-output-hk. This is why this pull request is marked as draft.

FAQ:

• Q: Isn't passing arguments to flakes frowned-upon?
  • A: Maybe, but it looks like it's eventually going to become a regular feature, so why not adopt this temporary workaround in the meanwhile?