gastownhall/beads · error

vendorHash not found in default.nix

Error message

vendorHash not found in default.nix

What it means

fixNixHash locates the vendorHash assignment using the regex `(vendorHash\s*=\s*)"([^"]+)"`. If no match is found in default.nix, the automated repair cannot proceed and this error is returned. This catches default.nix files that don't set vendorHash, or spell it differently (e.g. `vendorSha256` used by older Nixpkgs, or `outputHash` in vendored derivations).

Source

Thrown at cmd/bd/preflight.go:767

		)
	}

	nixPath := "default.nix"
	nixInfo, err := os.Stat(nixPath)
	if err != nil {
		return false, "", "", fmt.Errorf("cannot stat default.nix: %v", err)
	}
	nixPerm := nixInfo.Mode().Perm()

	content, err := os.ReadFile(nixPath)
	if err != nil {
		return false, "", "", fmt.Errorf("cannot read default.nix: %v", err)
	}

	re := regexp.MustCompile(`(vendorHash\s*=\s*)"([^"]+)"`)
	loc := re.FindSubmatchIndex(content)
	if loc == nil {
		return false, "", "", fmt.Errorf("vendorHash not found in default.nix")
	}
	oldHash := string(content[loc[4]:loc[5]])

	const sentinel = "sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="
	probed := append(append([]byte{}, content[:loc[4]]...), append([]byte(sentinel), content[loc[5]:]...)...)
	if err := os.WriteFile(nixPath, probed, nixPerm); err != nil {
		return false, "", "", fmt.Errorf("cannot write default.nix: %v", err)
	}

	restored := false
	defer func() {
		if !restored {
			_ = os.WriteFile(nixPath, content, nixPerm)
		}
	}()

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
	defer cancel()

View on GitHub (pinned to 71377f2769)

Solutions

1. Open default.nix and ensure it contains `vendorHash = "sha256-...";` inside buildGoModule — add or rename the attribute (e.g. change vendorSha256 to vendorHash if on a modern nixpkgs)
2. Then re-run `bd fix` so the automated hash repair can find and update it
3. If your derivation intentionally doesn't vendor Go modules, skip the nix fix entirely (the file legitimately has no vendorHash)

Example fix

// before (default.nix)
vendorSha256 = "sha256-old==";
// after
vendorHash = "sha256-old==";

grep -qE 'vendorHash\s*=\s*"[^"]+"' default.nix || { echo "default.nix lacks a vendorHash assignment"; exit 1; }

out, err := exec.Command("bd", "fix").CombinedOutput()
if err != nil && strings.Contains(string(out), "vendorHash not found in default.nix") {
    // add/rename the vendorHash attribute in default.nix, then retry
}

When it happens

Trigger: Running `bd fix` against a default.nix that lacks a `vendorHash = "..."` assignment, uses an attribute name other than vendorHash, formats it so the value is not a simple quoted string, or contains only commented-out vendorHash.

Common situations: Projects using the older `vendorSha256` attribute name from pre-23.05 nixpkgs; a mkGoModule/mkVendor derivation using `overrideAttrs` style hashes; hand-edited default.nix that dropped the vendorHash line.

Related errors

• could not parse correct hash from nix output: %s
• nix not found in PATH Manual fix: 1. Edit default.nix:
• dolt version output is unparseable
• embeddeddolt: requires CGO (build with CGO_ENABLED=1)
• errNoCGO

AI-assisted analysis of gastownhall/beads@71377f2769 (2026-08-30). Data as JSON: /api/errors/30b91bd537cda9b8. Report an issue: GitHub.