How to make cabal build to ignore ~/.cache/cabal

[yaitskov]

Hi,

I noticed that some packages from ~/.cache/cabal can contaminate cabal build.

cabal build is executed inside nix-shell which provides dependencies
and doesn't keep packages in ~/.cache/cabal,
but if somehow a package shows up in ~/.cache/cabal it overrides dependency from nixs-store.

Current workaround is just remove ~/.cache/cabal from time to time, but I would like to have an command line option or an environment variable to disable cache.

cabal --global --package-db= still looks at the cache folder.

[yaitskov]

cabal-install version 3.10.2.1
compiled using version 3.10.2.1 of the Cabal library

uname -a
Linux diehard 5.13.11 #1 SMP Sun Aug 15 11:46:11 EDT 2021 x86_64 GNU/Linux

    "nixpkgs": {
        "branch": "master",
        "description": "Nix Packages collection",
        "homepage": "",
        "owner": "NixOS",
        "repo": "nixpkgs",
        "rev": "5154a46001b1c012f63fa078a741449593545eec",
        "sha256": "136v59r9lsli97nzy26p1j1cqz7xcgrwdjvb8ndwhladzv7ih660",
        "type": "tarball",
        "url": "https://github.com/NixOS/nixpkgs/archive/5154a46001b1c012f63fa078a741449593545eec.tar.gz",
        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
    },

[yaitskov]

Update:

building cabal project with explicit even empty config files solves the issue.

cabal --config-file=foo build

[gbaz]

Note you can also override the cabal-dir using an environment variable (either xdg or cabal_dir specifically): #7386