golangci/golangci-lint · error

invalid source regex: %w

Error message

invalid source regex: %w

What it means

Validation guard in BaseRule.Validate: the 'source' field of a rule is set but failed to compile as a regular expression. validateOptionalRegex rejects the rule before it can be used for filtering issues; the regex compile error is preserved via %w.

Source

Thrown at pkg/config/base_rule.go:34

	// For compatibility with exclude-use-default/include.
	InternalReference string `mapstructure:"-"`
}

func (b *BaseRule) Validate(minConditionsCount int) error {
	if err := validateOptionalRegex(b.Path); err != nil {
		return fmt.Errorf("invalid path regex: %w", err)
	}

	if err := validateOptionalRegex(b.PathExcept); err != nil {
		return fmt.Errorf("invalid path-except regex: %w", err)
	}

	if err := validateOptionalRegex(b.Text); err != nil {
		return fmt.Errorf("invalid text regex: %w", err)
	}

	if err := validateOptionalRegex(b.Source); err != nil {
		return fmt.Errorf("invalid source regex: %w", err)
	}

	if b.Path != "" && b.PathExcept != "" {
		return errors.New("path and path-except should not be set at the same time")
	}

	nonBlank := 0
	if len(b.Linters) > 0 {
		nonBlank++
	}

	// Filtering by path counts as one condition, regardless how it is done (one or both).
	// Otherwise, a rule with Path and PathExcept set would pass validation
	// whereas before the introduction of path-except that wouldn't have been precise enough.
	if b.Path != "" || b.PathExcept != "" {
		nonBlank++
	}

View on GitHub (pinned to ed7a235d2d)

Solutions

1. Fix the `source` regex to valid Go RE2 syntax
2. Rewrite lookbehind/backreference patterns using RE2-compatible constructs
3. Prefer single-quoted YAML scalars for regexes to avoid backslash mangling
4. Validate the pattern compiles with Go's regexp before committing config

Example fix

# before
source: "(?<=foo)bar"
# after
source: 'foobar'

func checkSourceRegex(pattern string) error {
	if pattern == "" {
		return nil
	}
	_, err := regexp.Compile(pattern)
	return err
}
// before running: checkSourceRegex(rule.Source)

When it happens

Trigger: An exclusion/inclusion rule sets `source` to a pattern Go's regexp package cannot compile — syntax errors or RE2-unsupported features like lookbehinds and backreferences.

Common situations: Reusing PCRE-style source filters from other linters; regexes with `(?<=...)` lookbehinds; escaping mistakes in YAML double-quoted strings.

Related errors

• invalid path regex: %w
• invalid path-except regex: %w
• invalid text regex: %w
• the configuration contains invalid elements
• the configuration contains invalid elements

AI-assisted analysis of golangci/golangci-lint@ed7a235d2d (2026-09-02). Data as JSON: /api/errors/dfe0ff3fa3ea9e4f. Report an issue: GitHub.