What causes "run_as_user is not supported on Windows" in chenhg5/cc-connect?

Remove the run_as_user setting from config.toml on Windows hosts.

run_as_user is not supported on Windows

Error message

run_as_user is not supported on Windows

What it means

The Windows build of VerifyRunAsUserCheap always fails with this error because run_as_user isolation depends on sudo, which does not exist on Windows. The empty-runAsUser case returns nil (nothing to verify), but any real user yields this unsupported-platform error. It mirrors the Unix implementation's signature so callers need no build-tag branching.

Source

Thrown at core/runas_windows.go:55

// SudoRunner is a stub interface on Windows for API compatibility.
type SudoRunner interface {
	Run(ctx context.Context, args ...string) ([]byte, error)
}

// ExecSudoRunner is a stub on Windows.
type ExecSudoRunner struct{}

// Run always fails on Windows.
func (ExecSudoRunner) Run(ctx context.Context, args ...string) ([]byte, error) {
	return nil, errors.New("sudo is not supported on Windows")
}

// VerifyRunAsUserCheap always fails on Windows.
func VerifyRunAsUserCheap(_ context.Context, _ SudoRunner, runAsUser string) error {
	if runAsUser == "" {
		return nil
	}
	return errors.New("run_as_user is not supported on Windows")
}

View on GitHub (pinned to 4000b2338a)

Solutions

Remove the run_as_user setting from config.toml on Windows hosts.
Deploy cc-connect on a Unix-like OS when run_as_user isolation is required.
Check runtime.GOOS before configuring run_as_user and warn instead of attempting verification.

Example fix

// before
if err := core.VerifyRunAsUserCheap(ctx, runner, cfg.RunAsUser); err != nil {
    return err
}
// after
if runtime.GOOS == "windows" {
    return fmt.Errorf("run_as_user is not supported on Windows; unset it in config.toml")
}
if err := core.VerifyRunAsUserCheap(ctx, runner, cfg.RunAsUser); err != nil {
    return err
}

Defensive patterns

Strategy: validation

Validate before calling

if runtime.GOOS == "windows" && cfg.RunAsUser != "" {
    return errors.New("run_as_user cannot be used on Windows; remove it from config")
}

Try / catch

if err := core.VerifyRunAsUserCheap(ctx, runner, user); err != nil {
    if runtime.GOOS == "windows" {
        return fmt.Errorf("isolation unsupported here: %w", err)
    }
    return err
}

Prevention

Validate at config-load time that run_as_user is only set on Unix hosts.
Reuse configs across OSes only after stripping OS-specific keys.
Surface the unsupported-platform error in doctor output for Windows users.

When it happens

Trigger: Calling VerifyRunAsUserCheap with a non-empty runAsUser on a Windows build (core/runas_windows.go:55), e.g. from newClaudeSession during session creation with run_as_user configured.

Common situations: Config copied from a Linux deployment (containing run_as_user) run on Windows; unit/integration tests on a windows runner; users attempting sandboxed agents on a Windows desktop.

Understand the failure class

Background: "unsupported platform" / "not supported on this platform" errors: what they mean and how to fix them — this error's family across 47 libraries.

Related errors

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/a05cfb6cc0f49b30. Report an issue: GitHub.