caddyserver/caddy · error

compiling matcher regexp %s: %v

Error message

compiling matcher regexp %s: %v

What it means

Error "compiling matcher regexp %s: %v" thrown in caddyserver/caddy.

Source

Thrown at modules/caddytls/matchers.go:181

	// The regular expression to evaluate, in RE2 syntax,
	// which is the same general syntax used by Go, Perl,
	// and Python. For details, see
	// [Go's regexp package](https://golang.org/pkg/regexp/).
	// Captures are accessible via placeholders. Unnamed
	// capture groups are exposed as their numeric, 1-based
	// index, while named capture groups are available by
	// the capture group name.
	Pattern string `json:"pattern"`

	compiled *regexp.Regexp
}

// Provision compiles the regular expression which may include placeholders.
func (mre *MatchRegexp) Provision(caddy.Context) error {
	repl := caddy.NewReplacer()
	re, err := regexp.Compile(repl.ReplaceAll(mre.Pattern, ""))
	if err != nil {
		return fmt.Errorf("compiling matcher regexp %s: %v", mre.Pattern, err)
	}
	mre.compiled = re
	return nil
}

// Validate ensures mre is set up correctly.
func (mre *MatchRegexp) Validate() error {
	if mre.Name != "" && !wordRE.MatchString(mre.Name) {
		return fmt.Errorf("invalid regexp name (must contain only word characters): %s", mre.Name)
	}
	return nil
}

// Match returns true if input matches the compiled regular
// expression in m. It sets values on the replacer repl
// associated with capture groups, using the given scope
// (namespace).
func (mre *MatchRegexp) Match(input string, repl *caddy.Replacer) bool {

View on GitHub (pinned to 50e54ee279)

Solutions

1. Fix the regular expression syntax; the wrapped error explains the compile failure.

When it happens

Trigger: Thrown at modules/caddytls/matchers.go:181 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of caddyserver/caddy@50e54ee279 (2026-08-15). Data as JSON: /api/errors/bb4a9287a63cf6b2. Report an issue: GitHub.