Function classifyConnectionError

src/utils/error-classifier.ts:60–90

(
  error: unknown,
  connectorType: ConnectorType,
  sourceId: string
)

 * Pure; never throws.
 */
export function classifyConnectionError(
  error: unknown,
  connectorType: ConnectorType,
  sourceId: string
): { code: ConnectionErrorCode; message: string } | null {
  if (!error || typeof error !== "object") {
    return null;
  }
  const err = error as Record<string, unknown>;

  // Tunnel marker wins over the underlying network code.
  if (err[TUNNEL_ERROR_MARKER] === true) {
    return { code: "TUNNEL_FAILED", message: tunnelMessage(sourceId) };
  }

  const code = err.code;
  if (typeof code === "string" && NETWORK_CODES.has(code)) {
    return { code: "SOURCE_UNREACHABLE", message: unreachableMessage(sourceId) };
  }

  const authCodes = AUTH_CODES[connectorType];
  const errno = err.errno;
  if (
    (typeof code === "string" && authCodes.includes(code)) ||
    (typeof errno === "number" && authCodes.includes(errno))
  ) {
    return { code: "AUTH_FAILED", message: authMessage(sourceId) };
  }

  return null;
}