fix benchmark extrinsic creation

node/src/service/client.rs

@@ -16,8 +16,8 @@
 
 use common_runtime::{AccountId, Balance, Block, BlockNumber, Hash, Header, Index};
 use sc_client_api::{
-    AuxStore, Backend as BackendT, BlockchainEvents, KeysIter, MerkleValue, PairsIter,
-    UsageProvider,
+    AuxStore, Backend as BackendT, BlockBackend, BlockchainEvents, KeysIter, MerkleValue,
+    PairsIter, UsageProvider,
 };
 use sp_api::{CallApiAt, ProvideRuntimeApi};
 use sp_blockchain::{HeaderBackend, HeaderMetadata};
@@ -26,7 +26,7 @@ use sp_core::{Encode, Pair};
 use sp_runtime::{
     generic::SignedBlock,
     traits::{BlakeTwo256, Block as BlockT},
-    Justifications,
+    Justifications, SaturatedConversion,
 };
 use sp_storage::{ChildInfo, StorageData, StorageKey};
 use std::sync::Arc;
@@ -385,9 +385,10 @@ impl frame_benchmarking_cli::ExtrinsicBuilder for Client {
                         let signer = sp_keyring::Sr25519Keyring::Bob.pair();
 
                         let period = super::runtime_executor::runtime::BlockHashCount::get().checked_next_power_of_two().map(|c| c / 2).unwrap_or(2) as u64;
-                let genesis = client.usage_info().chain.best_hash;
+                        let genesis = client.block_hash(0).ok().flatten().expect("Genesis block exists; qed");
+        let best_block = client.chain_info().best_number;
 
-                Ok(client.sign_call(call, nonce, 0, period, genesis, signer))
+                        Ok(client.sign_call(call, nonce, best_block.saturated_into(), period, genesis, signer))
                     }
                 }
     }