Combining Checkers and Fetchers

A Checker selects the Version to lock. A Fetcher determines how to obtain the contents of that Version. They do not need to use the same platform.

Get a version from crates.io

{ pin }: {
  ripgrep = pin.mk {
    checker = pin.checker.crate { target = "ripgrep"; };
    fetcher = pin.fetcher.zip {
      url = version: "https://github.com/BurntSushi/ripgrep/archive/refs/tags/${version}.tar.gz";
    };
  };
}

This example reads the version from crates.io but fetches source from a GitHub archive. Before using it, confirm that registry versions match repository tag names. A Fetcher's version mapping does not change the original Version stored in the Pins File.

Track a Git branch

{ pin }: {
  project = pin.git {
    target = "https://github.com/NixOS/patchelf.git";
    mode = "branch";
    branch = "master";
  };
}

Git's head, branch, and ref modes return a commit ID; tag mode returns the original tag. Even as the branch advances, downstream consumers use the commit locked in the Pins File.

Get a version from npm

{ pin }: {
  vite = pin.mk {
    checker = pin.checker.npm { target = "vite"; distTag = "latest"; };
    fetcher = pin.fetcher.url {
      url = version: "https://registry.npmjs.org/vite/-/vite-${version}.tgz";
    };
  };
}

url keeps the downloaded file, while zip extracts supported archives. Choose based on whether the downstream project needs the file itself or a source directory.

See Checkers and Fetchers for all built-in options.