Function formatExplicitPortUnavailableError

browse/src/server.ts:813–827

(
  port: number,
  result: Extract<PortCheckResult, { available: false }>
)

}

function formatExplicitPortUnavailableError(
  port: number,
  result: Extract<PortCheckResult, { available: false }>
): Error {
  if (isOccupiedPort(result)) {
    return new Error(`[browse] Port ${port} (from BROWSE_PORT env) is in use`);
  }

  const detail = result.code ? `${result.code}: ${result.message}` : result.message;
  return new Error(
    `[browse] Cannot bind BROWSE_PORT=${port} on 127.0.0.1 (${detail}). ` +
    `This usually means localhost port binding is blocked by the current sandbox or OS permissions, ` +
    `not that the port is occupied. Allow localhost binding, or run browse from an unrestricted terminal.`
  );
}

function formatRandomPortUnavailableError(attempts: FailedPortAttempt[]): Error {
  const blockingAttempts = attempts.filter((attempt) => !isOccupiedPort(attempt.result));