go-task/task · error

task: --json only applies to --list or --list-all

Error message

task: --json only applies to --list or --list-all

What it means

Flag validation error raised by the Validate function after CLI parsing before task execution. It fires when --json is passed without either --list or --list-all; JSON formatting of task listings is only supported for those two listing modes, so the flag has no effect otherwise. Fix by adding --list or --list-all, or removing --json.

Source

Thrown at internal/flags/flags.go:233

	if Output.Name != "group" {
		if Output.Group.Begin != "" {
			return errors.New("task: You can't set --output-group-begin without --output=group")
		}
		if Output.Group.End != "" {
			return errors.New("task: You can't set --output-group-end without --output=group")
		}
		if Output.Group.ErrorOnly {
			return errors.New("task: You can't set --output-group-error-only without --output=group")
		}
	}

	if List && ListAll {
		return errors.New("task: cannot use --list and --list-all at the same time")
	}

	if ListJson && !List && !ListAll {
		return errors.New("task: --json only applies to --list or --list-all")
	}

	if NoStatus && !ListJson {
		return errors.New("task: --no-status only applies to --json with --list or --list-all")
	}

	if Nested && !ListJson {
		return errors.New("task: --nested only applies to --json with --list or --list-all")
	}

	// Validate certificate flags
	if (Cert != "" && CertKey == "") || (Cert == "" && CertKey != "") {
		return errors.New("task: --cert and --cert-key must be provided together")
	}

	return nil
}

View on GitHub (pinned to 385e5ad92a)

Solutions

1. Use `--json --list --no-status` (or --list-all) as the full flag set
2. Remove --no-status if you don't want JSON list output
3. Fix scripts so --no-status is only added when --json listing is enabled

Example fix

# before
task --list --no-status

# after
task --list --json --no-status

if flags.NoStatus && !flags.ListJson {
	return errors.New("--no-status requires --json with --list or --list-all")
}

if err := flags.Validate(); err != nil {
	if strings.Contains(err.Error(), "--no-status only applies") {
		fmt.Fprintln(os.Stderr, "use: task --list --json --no-status")
		os.Exit(2)
	}
	return err
}

When it happens

Trigger: Running `task --no-status` (or with --list/--list-all but without --json) so NoStatus is true while ListJson is false when Validate() executes.

Common situations: CI scripts passing --no-status for compact output but missing the required --json --list combination; stale documentation examples.

Understand the failure class

Background: "mutually exclusive" flag errors: what "can't supply both nx and xx", "--raw is not compatible with -i" and "cannot be used with" mean, and how to fix them — this error's family across 29 libraries.

Related errors

• task: cannot use --list and --list-all at the same time
• task: --no-status only applies to --json with --list or --li
• task: You can't set both --download and --offline flags
• task: You can't set both --download and --clear-cache flags
• task: You can't set both --global and --dir

AI-assisted analysis of go-task/task@385e5ad92a (2026-09-05). Data as JSON: /api/errors/b3459a58ccb0c241. Report an issue: GitHub.