nix: Fix the cargo-bundle override

[rrbutani]

With the recent deprecation of rustPlatform.fetchCargoTarball + migration to using fetchCargoVendor by default in buildRustPackage (NixOS/nixpkgs#394012), the cargo-bundle override strategy used here, as prescribed by the
nixos asia wiki no longer works:

zed/nix/build.nix

Lines 100 to 116 in c6e2d20

	(cargo-bundle.overrideAttrs (
	new: old: {
	version = "0.6.1-zed";
	src = fetchFromGitHub {
	owner = "zed-industries";
	repo = "cargo-bundle";
	rev = "2be2669972dff3ddd4daf89a2cb29d2d06cad7c7";
	hash = "sha256-cSvW0ND148AGdIGWg/ku0yIacVgW+9f1Nsi+kAQxVrI=";
	};
	# https://nixos.asia/en/buildRustPackage
	cargoDeps = old.cargoDeps.overrideAttrs ({
	inherit src;
	name = "${new.pname}-${new.version}-vendor.tar.gz";
	outputHash = "sha256-Q49FnXNHWhvbH1LtMUpXFcvGKu9VHwqOXXd+MjswO64=";
	});
	}
	))

fetchCargoTarball produced a single derivation but fetchCargoVendor produces two:

• ${name}-vendor-staging (inner; FoD)
• ${name}-vendor (outer)

overrideAttrs here is setting outputHash on the latter (which isn't a fixed-output-derivation and does not have outputHashMode set which implies outputHashMode = "flat") instead of the inner; this results in errors like this:

❯ nix develop
error: output path '/nix/store/cb57w05zvsqxshqjl789kmsy9pbqjn06-cargo-bundle-0.6.1-zed-vendor.tar.gz' should be a non-executable regular file since recursive hashing is not enabled (outputHashMode=flat)
error: 1 dependencies of derivation '/nix/store/k3azmxljgjn26hqyhg9m1y3lhx32y939-cargo-bundle-0.6.1-zed.drv' failed to build
error: 1 dependencies of derivation '/nix/store/8ag4v0m90m4kcaq1ypp7f85pp8s6fxgc-nix-shell-env.drv' failed to build

Note

you will need to remove /nix/store/cb57w05zvsqxshqjl789kmsy9pbqjn06-cargo-bundle-0.6.1-zed-vendor.tar.gz
from your nix store in order to be able to reproduce this

We want to be setting outputHash on the first derivation instead. This change has us just do the call to fetchCargoTarball manually instead of using overrides.

---

I suspect CI/other machines didn't catch this due to a store path matching the name + outputHash already being present but I'm not entirely sure how this happened...

sha256-Q49FnXNHWhvbH1LtMUpXFcvGKu9VHwqOXXd+MjswO64= is actually a fetchCargoTarball hash, not a fetchCargoVendor hash (and upstream cargo-about's cargoDeps has been using cargoVendor since before the nixpkgs bump in 50ad71a)

---

Note

eventually we'll be able to just have .overrideAttrs (_: { cargoHash = "..."; }) work as expected ¹

---

Release Notes:

• N/A

Footnotes

1. now that buildRustPackage uses lib.extendMkDerivation (NixOS/nixpkgs/#234651) the groundwork is in place; a follow PR needs to use cargoHash and friends from finalAttrs ↩

[P1n3appl3]

Thanks for the fix and the clear/detailed explanation!