helix-editor/helix · error

unexpected double dash argument: {}

Error message

unexpected double dash argument: {}

What it means

Catch-all for any unrecognized long option: after all known '--' flags are matched, any argument starting with '--' that is not '--' itself (the literal separator) bails with 'unexpected double dash argument: <arg>'. This is Helix's unknown-option error, deliberately distinguishing long flags from the short-flag cluster handling that follows.

Source

Thrown at helix-term/src/args.rs:95

                    Some(path) => args.log_file = Some(path.into()),
                    None => anyhow::bail!("--log must specify a path to write"),
                },
                "-w" | "--working-dir" => match argv.next().as_deref() {
                    Some(path) => {
                        args.working_directory = if Path::new(path).is_dir() {
                            Some(PathBuf::from(path))
                        } else {
                            anyhow::bail!(
                                "--working-dir specified does not exist or is not a directory"
                            )
                        }
                    }
                    None => {
                        anyhow::bail!("--working-dir must specify an initial working directory")
                    }
                },
                arg if arg.starts_with("--") => {
                    anyhow::bail!("unexpected double dash argument: {}", arg)
                }
                arg if arg.starts_with('-') => {
                    let arg = arg.get(1..).unwrap().chars();
                    for chr in arg {
                        match chr {
                            'v' => args.verbosity += 1,
                            'V' => args.display_version = true,
                            'h' => args.display_help = true,
                            _ => anyhow::bail!("unexpected short arg {}", chr),
                        }
                    }
                }
                "+" => line_number = usize::MAX,
                arg if arg.starts_with('+') => {
                    match arg[1..].parse::<usize>() {
                        Ok(n) => line_number = n.saturating_sub(1),
                        _ => insert_file_with_position(arg),
                    };

View on GitHub (pinned to 079a789e8c)

Solutions

1. Check 'hx --help' for the supported long options and correct the flag
2. Use the '--' separator if the token is actually a FILE whose name starts with '--': hx -- --weird-filename
3. Update scripts after Helix upgrades - flags occasionally move (e.g. grammar/log/config/working-dir all take values)

Example fix

# before
hx --wait file.rs

# after
hx file.rs
hx -- --strange-file-name   # to open a file starting with --

# Script guard: verify long flags against the known set before exec
known='--version --help --strict --tutor --vsplit --hsplit --health --grammar --config --log --working-dir --'
for a in "$@"; do
  case " $known " in
    *" $a "*) ;;
    --*) echo "unknown flag: $a" >&2; hx --help >&2; exit 2;;
  esac
done
exec hx "$@"

When it happens

Trigger: 'hx --nushell', 'hx --vs-split', 'hx --file a.txt' - any typo'd or unsupported long flag. Note everything after a bare '--' is treated as filenames and never reaches this arm.

Common situations: Flags from other editors' muscle memory (--wait, --new-window, --diff); typos (--vplits); flags removed or renamed across Helix versions; scripts written against clap-style flag sets that don't exist here.

Related errors

• expected a path to file, but found a directory: {file:?}. (t
• can only set a split once of a specific type
• --grammar must be followed by either 'fetch' or 'build'
• --config must specify a path to read
• --log must specify a path to write

AI-assisted analysis of helix-editor/helix@079a789e8c (2026-08-16). Data as JSON: /api/errors/61521ab4203e2a0a. Report an issue: GitHub.