argoproj/argo-workflows · error

invalid shell %q: supported shells are bash, zsh, and fish

Error message

invalid shell %q: supported shells are bash, zsh, and fish

What it means

`argo completion <shell>` looks up the shell name in a fixed map containing only bash, zsh, and fish. Any other string reaches the default path and returns this error. Note powershell completion is not offered by this command even though cobra supports it.

Source

Thrown at cmd/argo/commands/completion.go:144

For zsh, output to a file in a directory referenced by the $fpath shell
variable.

For fish, output to a file in ~/.config/fish/completions
`,
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			shell := args[0]
			rootCommand := NewCommand()
			rootCommand.BashCompletionFunction = bashCompletionFunc
			availableCompletions := map[string]func(out io.Writer, cmd *cobra.Command) error{
				"bash": runCompletionBash,
				"zsh":  runCompletionZsh,
				"fish": runCompletionFish,
			}
			completion, ok := availableCompletions[shell]
			if !ok {
				return fmt.Errorf("invalid shell %q: supported shells are bash, zsh, and fish", shell)
			}
			return completion(os.Stdout, rootCommand)
		},
	}
	return command
}

func runCompletionBash(out io.Writer, cmd *cobra.Command) error {
	return cmd.GenBashCompletion(out)
}

func runCompletionZsh(out io.Writer, cmd *cobra.Command) error {
	return cmd.GenZshCompletion(out)
}

func runCompletionFish(out io.Writer, cmd *cobra.Command) error {
	return cmd.GenFishCompletion(out, true)
}

View on GitHub (pinned to 35bff19146)

Solutions

1. Use one of: `argo completion bash`, `argo completion zsh`, `argo completion fish`
2. For PowerShell, generate bash-compatible completion is not available — use the shell's own completion for external tools or file an upstream feature request
3. For POSIX sh, source bash completion under bash or use fish/zsh instead
4. Check spelling and casing: the shell argument must be exactly lowercase bash/zsh/fish

Example fix

// before
argo completion powershell
// after
argo completion bash   # or zsh / fish

case "$shell" in
  bash|zsh|fish) argo completion "$shell";;
  *) echo "unsupported shell: $shell (use bash|zsh|fish)" >&2; exit 1;;
esac

When it happens

Trigger: Running `argo completion powershell`, `argo completion sh`, `argo completion Bash` (case-sensitive map), or `argo completion` with an empty/typo'd argument.

Common situations: Windows/PowerShell users expecting a powershell subcommand; POSIX `sh` (dash) users; scripts generating completion for a shell name held in a variable with wrong case or whitespace.

Related errors

• unknown output mode: %s
• failed to get existing cluster workflow template %q to updat
• failed to update cluster workflow template: %s, %w
• error converting %s: %w
• failed to parse TypeMeta: %w

AI-assisted analysis of argoproj/argo-workflows@35bff19146 (2026-09-03). Data as JSON: /api/errors/7b01458728e1c486. Report an issue: GitHub.