RuleLoadError

The Cause

A rule module does not export its rule using a default export

A rule module was loaded but does not export its rule using a default export. Thymian rules and rule sets must be exported using export default (ES modules) or module.exports = (CommonJS).

The rule source specifier could not be resolved

Cannot resolve rule source <input>.

The rule source could not be found. A ruleSets: config entry or a --rule-set value is a rule-set package name or a local path with an explicit extension. This error means the specifier matched neither an installed package nor a file on disk. (A glob is not a valid specifier here — globbing is a rule set’s own pattern: field.)

The rule source specifier resolved, but was refused for what it is

Cannot load rule source <input>: <reason>.

The path exists but is not a loadable module kind — see UserModuleLoadError for the full list of reasons (a .d.ts file, .mts/.cts, a missing extension, unbuilt TypeScript in a package, …).

A glob-matched rule set file failed to load

Rule set "<name>" failed to load "<path>": <error>

A file matched by a rule set’s glob pattern resolved and began loading, but threw before finishing (a syntax error, a throwing top-level statement).

A glob matched a nested rule set

"<path>" is a rule set; rule sets cannot contain rule sets.

Rule sets are flat: a glob match whose default export is itself a rule set is an error, not a nested load. See Loading Rules and Plugins.

A glob matched files but produced no loadable rules

Rule set "<name>" pattern matched files but produced no loadable rules.

The glob pattern matched at least one file, but none of the matches were loadable rules — this throws rather than silently resolving to an empty rule set.

The Solution

Make sure your rule file exports the rule or rule set as the default export.

For example, if you have a rule file my-rule.ts:

// ❌ Incorrect - named export
export const myRule = {/* rule definition */};

// ✅ Correct - default export
export default {/* rule definition */};

For the resolution and loading causes above, check the specifier or glob pattern matches the file you intended, and that the file is a loadable kind — see Loading Rules and Plugins for the full contract.