datasource/ethereum: Assert calls len > 0 in `EthereumAdapter`
@@ -684,6 +684,7 @@ where
// incorrect block_hash we can catch this and error. But if the call streams returns no calls
// for the correct block_number but the incorrect block_hash, there is no way to tell.
// Since we are asking for all the calls in the block this is not a problem.
+ assert!(calls.len() > 0);
for call in calls.iter() {
if call.block_hash != block_hash {
return future::err(format_err!(
