golang/go · error

did not find package for %s in go list output

Error message

did not find package for %s in go list output

What it means

Thrown by 'go tool cover' findFile (func.go) when a source file path from the coverage profile cannot be mapped to a package in the `go list -json` output. findFile looks up pkgs[path.Dir(file)]; if no package owns that directory and there's no pkg.Error, the file is unresolvable.

Source

Thrown at src/cmd/cover/func.go:240

	return pkgs, nil
}

// findFile finds the location of the named file in GOROOT, GOPATH etc.
func findFile(pkgs map[string]*Pkg, file string) (string, error) {
	if strings.HasPrefix(file, ".") || filepath.IsAbs(file) {
		// Relative or absolute path.
		return file, nil
	}
	pkg := pkgs[path.Dir(file)]
	if pkg != nil {
		if pkg.Dir != "" {
			return filepath.Join(pkg.Dir, path.Base(file)), nil
		}
		if pkg.Error != nil {
			return "", errors.New(pkg.Error.Err)
		}
	}
	return "", fmt.Errorf("did not find package for %s in go list output", file)
}

func percent(covered, total int64) float64 {
	if total == 0 {
		total = 1 // Avoid zero denominator.
	}
	return 100.0 * float64(covered) / float64(total)
}

View on GitHub (pinned to b6b368adc5)

Solutions

1. Regenerate the coverage profile in the current checkout (`go test -coverprofile=...`)
2. Ensure you run `go tool cover` from the same module root where the test ran
3. If the file path is absolute or relative ('.'/'..'), findFile short-circuits — convert external paths accordingly

Example fix

# before (stale profile from another checkout)
go tool cover -func=old.out
# after
go test -coverprofile=c.out ./...
go tool cover -func=c.out

# Confirm every profile file's dir maps to a package before reporting
for f in $(awk '{print $1}' c.out | cut -d: -f1); do
  d=$(dirname "$f"); go list -e "$d" >/dev/null 2>&1 || echo "unresolved: $f"
done

When it happens

Trigger: `go tool cover -func=profile.out` / `-html` where the profile references a file whose directory is not a package known to `go list` — e.g. a generated file whose directory was removed, a vendored path, or a stale profile from a different checkout.

Common situations: Profile generated in one checkout/module then consumed in another where the package layout differs. Deleted or moved packages. Files under /tmp or non-module paths. Stale profile after a refactor.

Related errors

• cannot run go list: %v %s
• decoding go list json: %v
• can't read %q: %v
• too many options
• -var: %q is not a valid identifier

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/7d3b1a029d7a32da. Report an issue: GitHub.