-So if you want to differentiate between "transaction failed" and
-"succeeded" then your C<$code_ref> should never return C<undef>
-itself.
+If you just use the snippet above, your code will catch everything related to
+the transaction aborting, but will not catch other errors that might have been
+thrown. The transaction will be rolled back in both cases.
+
+If you want to play nice in case your transaction is embedded in another
+transaction, just rethrow the error:
+
+ $db->with_transaction(sub {
+ # code deep in the engine
+ 1;
+ }) or die $db->error;
+
+=back