Thanks!

I think the merging logic would need to be adapted to propagate the more problematic exception, instead of keeping the same exception type it has to start with.

In particular for this codepath:

		try {
			if (!error.HasError()) {
				// Commit the transaction.
				error = transaction_manager.CommitTransaction(context, transaction);
			} else {
				// Rollback due to previous error.
				transaction_manager.RollbackTransaction(transaction);
			}
		} catch (std::exception &ex) {
			error.Merge(ErrorData(ex));
		}

Say there is an error already entering this codepath, say an OutOfMemoryException, and say that RollbackTransaction throws something that should invalidate like a FatalException.

Now instead of throwing a FatalException, an OutOfMemory is re-thrown, and this might end up being ignored.

The other two codepaths I think after this PR are in a better state, but still can benefit from improved merging logic.