astral-sh/ruff · error · anyhow::Error

{e}

Error message

{e}

What it means

`ty rule <name>` resolves the argument through the default lint registry; this anyhow wrapper just forwards the registry's `GetLintError` Display text. In practice the message is one of: `Unknown rule \`name\`` (optionally with `Did you mean \`...\`?` from fuzzy matching), `Removed rule \`name\``, or the prefixed-with-category form that suggests the unprefixed name — all meaning the given name does not resolve to a currently selectable lint.

Source

Thrown at crates/ty/src/rule.rs:53

        let status = match self.status {
            LintStatus::Stable { since } => format!("Stable (since {since})"),
            LintStatus::Deprecated { since, reason } => {
                format!("Deprecated (since {since}): {reason}")
            }
            LintStatus::Removed { since, reason } => format!("Removed (since {since}): {reason}"),
        };

        writeln!(f, "Default level: {} | {status}\n", self.default_level)?;

        f.write_str(self.documentation.trim())
    }
}

/// Explain a single rule.
pub(crate) fn rule(name: &str, format: HelpFormat) -> Result<()> {
    let registry = default_lint_registry();
    let lint = registry.get(name).map_err(|e| anyhow::anyhow!("{e}"))?;

    let mut stdout = BufWriter::new(io::stdout().lock());
    match format {
        HelpFormat::Text => {
            writeln!(stdout, "{}", Explanation::from_lint(&lint))?;
        }
        HelpFormat::Json => {
            serde_json::to_writer_pretty(&mut stdout, &Explanation::from_lint(&lint))?;
        }
    }
    Ok(())
}

/// Explain all rules.
pub(crate) fn rules(format: HelpFormat) -> Result<()> {
    let registry = default_lint_registry();
    let mut lints: Vec<LintId> = registry.lints().to_vec();
    lints.sort_by_key(|l| l.name());

View on GitHub (pinned to 672bb4edf0)

Solutions

1. Apply the `Did you mean ...` suggestion printed in the error, if present
2. List exact current names with `ty rules` (or `ty rules --format json`) and copy the name verbatim
3. For a `Removed rule` message, read the removal version/reason shown by the registry and switch to the replacement rule

Example fix

# before
ty rule unresolveed-import
# after (use the suggested/actual name)
ty rule unresolved-import

ty rules | grep -Fx "$RULE_NAME" >/dev/null \
  || { echo "unknown rule: $RULE_NAME" >&2; exit 2; }

When it happens

Trigger: `ty rule unresolved-imports` (typo), passing a name that was removed in an earlier ty release (registry entry now `LintStatus::Removed`), or passing a name that still carries its category prefix; the registry suggests a close name when one exists.

Common situations: Copy-pasting rule names from older docs, issue threads, or `# ty: ignore` comments; scripts that loop over rule names and feed them to `ty rule`; shell-history typos.

Related errors

• Provided project path `{project}` is not a directory
• {flag} <reason> cannot contain newline characters
• The current working directory `{}` contains non-Unicode char
• `--watch` is not supported with uv workspace integration
• could not find task named `{}`

AI-assisted analysis of astral-sh/ruff@672bb4edf0 (2026-08-16). Data as JSON: /api/errors/f93d393e7c050201. Report an issue: GitHub.