caddyserver/caddy · error

adding regexp operation for field %s: %v

Error message

adding regexp operation for field %s: %v

What it means

Error "adding regexp operation for field %s: %v" thrown in caddyserver/caddy.

Source

Thrown at modules/logging/filterencoder.go:245

			err := parseField()
			if err != nil {
				return err
			}
		}
	}

	// After parsing all fields, merge multiple regexp filters into MultiRegexpFilter
	for field, filters := range regexpFilters {
		if len(filters) == 1 {
			// Single regexp filter, use the original RegexpFilter
			fe.FieldsRaw[field] = caddyconfig.JSONModuleObject(filters[0], "filter", "regexp", nil)
		} else {
			// Multiple regexp filters, merge into MultiRegexpFilter
			multiFilter := &MultiRegexpFilter{}
			for _, regexpFilter := range filters {
				err := multiFilter.AddOperation(regexpFilter.RawRegexp, regexpFilter.Value)
				if err != nil {
					return fmt.Errorf("adding regexp operation for field %s: %v", field, err)
				}
			}
			fe.FieldsRaw[field] = caddyconfig.JSONModuleObject(multiFilter, "filter", "multi_regexp", nil)
		}
	}

	return nil
}

// AddArray is part of the zapcore.ObjectEncoder interface.
// Array elements do not get filtered.
func (fe FilterEncoder) AddArray(key string, marshaler zapcore.ArrayMarshaler) error {
	if filter, ok := fe.Fields[fe.keyPrefix+key]; ok {
		filter.Filter(zap.Array(key, marshaler)).AddTo(fe.wrapped)
		return nil
	}
	return fe.wrapped.AddArray(key, marshaler)
}

View on GitHub (pinned to 50e54ee279)

Solutions

1. Fix the regexp operation for the named field; the wrapped error explains the compile failure.

When it happens

Trigger: Thrown at modules/logging/filterencoder.go:245 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/ac9235a277747a06. Report an issue: GitHub.