From f3880126eeffb978f31059738112645f57612f3e Mon Sep 17 00:00:00 2001
From: Harry Kalodner <harry@offchainlabs.com>
Date: Mon, 29 Aug 2022 22:42:25 -0400
Subject: [PATCH] Support optional block num arg for estimate gas

---
 packages/arb-rpc-node/dev/fees_test.go  | 2 +-
 packages/arb-rpc-node/web3/eth.go       | 9 ++++++---
 packages/arb-rpc-node/web3/ethclient.go | 2 +-
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/packages/arb-rpc-node/dev/fees_test.go b/packages/arb-rpc-node/dev/fees_test.go
index ea2ac440f8..19ac91653e 100644
--- a/packages/arb-rpc-node/dev/fees_test.go
+++ b/packages/arb-rpc-node/dev/fees_test.go
@@ -326,7 +326,7 @@ func TestNonAggregatorFee(t *testing.T) {
 			To:         &simpleAddr,
 			Data:       (*hexutil.Bytes)(&data),
 			Aggregator: &emptyAgg,
-		})
+		}, nil)
 		test.FailIfError(t, err)
 		userOpts.GasLimit = uint64(estimatedGas)
 		t.Log("estimate:", userOpts.GasLimit)
diff --git a/packages/arb-rpc-node/web3/eth.go b/packages/arb-rpc-node/web3/eth.go
index 4a12b2c0f6..842360ef80 100644
--- a/packages/arb-rpc-node/web3/eth.go
+++ b/packages/arb-rpc-node/web3/eth.go
@@ -239,13 +239,16 @@ func (s *Server) Call(ctx context.Context, callArgs CallTxArgs, blockNum rpc.Blo
 	return res.ReturnData, nil
 }
 
-func (s *Server) EstimateGas(ctx context.Context, args CallTxArgs) (hexutil.Uint64, error) {
+func (s *Server) EstimateGas(ctx context.Context, args CallTxArgs, optBlockNum *rpc.BlockNumberOrHash) (hexutil.Uint64, error) {
 	if args.To != nil && *args.To == arbos.ARB_NODE_INTERFACE_ADDRESS {
 		// Fake gas for call
 		return hexutil.Uint64(21000), nil
 	}
-	blockNum := rpc.PendingBlockNumber
-	snap, err := s.getSnapshot(ctx, &blockNum)
+	blockNum := rpc.BlockNumberOrHashWithNumber(rpc.PendingBlockNumber)
+	if optBlockNum != nil {
+		blockNum = *optBlockNum
+	}
+	snap, err := s.getSnapshotForNumberOrHash(ctx, blockNum)
 	if err != nil {
 		return 0, err
 	}
diff --git a/packages/arb-rpc-node/web3/ethclient.go b/packages/arb-rpc-node/web3/ethclient.go
index 663733ff44..ad4f8fd196 100644
--- a/packages/arb-rpc-node/web3/ethclient.go
+++ b/packages/arb-rpc-node/web3/ethclient.go
@@ -152,7 +152,7 @@ func (c *EthClient) EstimateGas(ctx context.Context, call ethereum.CallMsg) (uin
 		Value:    (*hexutil.Big)(call.Value),
 		Data:     (*hexutil.Bytes)(&call.Data),
 	}
-	gas, err := c.srv.EstimateGas(ctx, args)
+	gas, err := c.srv.EstimateGas(ctx, args, nil)
 	if err != nil {
 		return 0, err
 	}