error: while calling the 'derivationStrict' builtin at /builtin/derivation.nix:9:12: (source not available)

OS Version: 24.10
OS Distro: Ubuntu

I run the install commands and everything looks like it's working until this:

Configured https://simula.cachix.org binary cache in /home/user/.config/nix/nix.conf

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error:
       … while calling the 'derivationStrict' builtin

         at /builtin/derivation.nix:9:12: (source not available)

       … while evaluating derivation 'Simula'
         whose name attribute is located at /nix/store/izxcyr1301yh0yi4g94ghfc72wrxn8sc-nixpkgs-24.05/pkgs/stdenv/generic/make-derivation.nix:331:7

       … while evaluating attribute 'src' of derivation 'Simula'

         at /home/user/Documents/VR/Simula/Simula.nix:338:7:

          337|       name = "Simula";
          338|       src = if externalSrc != null then externalSrc else localSrc;
             |       ^
          339|       buildInputs = [ xpra xrdb wmctrl fontconfig glibc-locales xfce4-terminal-wrapped openxr-loader midori-wrapped pernoscoSubmit i3status-wrapped cabal-install ghc ] ++ simulaPackages;

       error: '/home/user/Documents/VR/Simula' is a shallow Git repository, but shallow repositories are only allowed when `shallow = true;` is specified.

Please let me know what info to provide and I'll see what I can do. It's probably something silly that I missed.

Thanks and Happy Holidays.

Start by reproducing the install failure and inspect Simula.nix around line 338, where the derivation selects its source. Check how the local Git checkout is obtained and why its shallow state reaches this derivation. Done means the intended checkout is accepted and the Simula derivation completes successfully.