xai-org/x-algorithm · error · ConfigFailure

Field name '$fieldName' does not match $fieldNameRegex.

Error message

Field name '$fieldName' does not match $fieldNameRegex.

What it means

Field names in BotMaker configs (struct/dataclass fields passed through the codegen pipeline) must match fieldNameRegex. validateFieldName throws ConfigFailure naming both the field and the regex when the field identifier does not conform.

Source

Thrown at botmaker/src/scala/com/twitter/botmaker/runtime/config/ServiceConfigs.scala:72

  }

  def validate(condition: Boolean, err: String): Unit = {
    if (!condition) {
      throw ConfigFailure(err)
    }
  }

  def validateEventType(eventType: String): Unit = {
    if (eventTypeRegex.findFirstIn(eventType).isEmpty) {
      throw ConfigFailure(
        s"Event type '$eventType' does not match $eventTypeRegex."
      )
    }
  }

  def validateFieldName(fieldName: String): Unit = {
    if (fieldNameRegex.findFirstIn(fieldName).isEmpty) {
      throw ConfigFailure(
        s"Field name '$fieldName' does not match $fieldNameRegex."
      )
    }
  }

  def validateFuncName(funcName: String): Unit = {
    if (funcNameRegex.findFirstIn(funcName).isEmpty) {
      throw ConfigFailure(
        s"Func name '$funcName' does not match $funcNameRegex."
      )
    }
  }

  def validateEndpoint(endpoint: String): Unit = {
    if (endpoint != "ScribeClient"
      && endpointRegex.findFirstIn(endpoint).isEmpty) {
      throw ConfigFailure(
        s"Endpoint '$endpoint' does not match $endpointRegex."

View on GitHub (pinned to 24c60942c5)

Solutions

  1. Rename the field to plain alphanumeric identifier style (typically camelCase)
  2. If the source schema has odd keys, map them to safe Scala identifiers and translate at the serialization boundary
  3. Pre-validate all field names against the same regex in a unit test of your config module

Example fix

// before
case class Rule(match-threshold: Int) // invalid identifier

// after
case class Rule(matchThreshold: Int)
Defensive patterns

Strategy: type-guard

Validate before calling

FIELD_NAME_RE = re.compile(r'^[a-zA-Z][a-zA-Z0-9_]*$')
bad = [f for f in dataclass_fields(Cfg) if not FIELD_NAME_RE.match(f.name)]
assert not bad, bad

Type guard

def isValidFieldName(name: str) -> bool:
    return bool(re.match(r'^[a-zA-Z][a-zA-Z0-9_]*$', name))

Prevention

When it happens

Trigger: Defining a config data type whose field name fails fieldNameRegex — e.g. names with hyphens, '$', leading underscores or digits, or reserved punctuation — when the config is registered and validated.

Common situations: Mirroring an external JSON/Thrift schema whose keys contain dashes or '@'; Scala keywords or synthetic field names like 'x$1'; fields copied from YAML with odd characters.

Related errors

AI-assisted analysis of xai-org/x-algorithm@24c60942c5 (2026-08-28). Data as JSON: /api/errors/910cdd9b7af133aa. Report an issue: GitHub.