What causes "--log must specify a path to write" in helix-editor/helix?

Supply a writable path: hx --log /tmp/helix.log -v

--log must specify a path to write

Error message

--log must specify a path to write

What it means

The --log option requires a file path to write the log to; when no following token exists (argv.next() returned None) the parser bails. The value becomes args.log_file, overriding the default log location for this session.

Source

Thrown at helix-term/src/args.rs:78

                },
                "--health" => {
                    args.health = true;
                    args.health_arg = argv.next_if(|opt| !opt.starts_with('-'));
                }
                "-g" | "--grammar" => match argv.next().as_deref() {
                    Some("fetch") => args.fetch_grammars = true,
                    Some("build") => args.build_grammars = true,
                    _ => {
                        anyhow::bail!("--grammar must be followed by either 'fetch' or 'build'")
                    }
                },
                "-c" | "--config" => match argv.next().as_deref() {
                    Some(path) => args.config_file = Some(path.into()),
                    None => anyhow::bail!("--config must specify a path to read"),
                },
                "--log" => match argv.next().as_deref() {
                    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)
                }

View on GitHub (pinned to 079a789e8c)

Solutions

Supply a writable path: hx --log /tmp/helix.log -v
Ensure the directory exists and is writable (the log file is created/truncated)
For verbosity, combine with -v..vvvv; only the file path goes to --log

Example fix

# before
hx --log

# after
hx --log /tmp/helix.log -v file.rs

Defensive patterns

Strategy: validation

Validate before calling

# Ensure the log path is writable before launching
LOG="${LOG:-/tmp/helix.log}"
touch "$LOG" 2>/dev/null || { echo "cannot write $LOG" >&2; exit 2; }
exec hx --log "$LOG" -v "$@"

Prevention

Follow --log with a concrete writable file path
Create the parent directory first
Keep verbosity flags (-v..vvvv) separate from the log path

When it happens

Trigger: 'hx --log' as the final argument, or followed by another flag the user expected to be the log target's prefix; script truncation dropping the path.

Common situations: Copy-pasting a log command with the path lost in formatting; intending '--log <file> -v' but omitting the file; Windows path quoting issues leaving an empty next token after shell parsing.

Related errors

AI-assisted analysis of helix-editor/helix@079a789e8c (2026-08-16). Data as JSON: /api/errors/f51dc0405401af38. Report an issue: GitHub.