message: Turn this into an internal exception
diff: @@ -26,7 +26,9 @@ public:
  ~TransactionContext();
  MetaTransaction &ActiveTransaction() {
  - D_ASSERT(current_transaction);
  + if (!current_transaction) {
  + throw InternalException("TransactionContext::ActiveTransaction called without active transaction");
  + }
  return *current_transaction;
  }
  