fix: EthAPI: Make newEthBlockFromFilecoinTipSet faster and correct

node/impl/full/eth.go

@@ -1792,18 +1792,27 @@ func newEthBlockFromFilecoinTipSet(ctx context.Context, ts *types.TipSet, fullTx
 
 	block := ethtypes.NewEthBlock(len(msgs) > 0)
 
-	// this seems to be a very expensive way to get gasUsed of the block. may need to find an efficient way to do it
 	gasUsed := int64(0)
-	for txIdx, msg := range msgs {
-		msgLookup, err := sa.StateSearchMsg(ctx, types.EmptyTSK, msg.Cid(), api.LookbackNoLimit, false)
-		if err != nil || msgLookup == nil {
-			return ethtypes.EthBlock{}, nil
+	compOutput, err := sa.StateCompute(ctx, ts.Height(), nil, ts.Key())
+	if err != nil {
+		return ethtypes.EthBlock{}, xerrors.Errorf("failed to compute state: %w", err)
+	}
+
+	for txIdx, msg := range compOutput.Trace {
+		// skip system messages like reward application and cron
+		if msg.Msg.From == builtintypes.SystemActorAddr {
+			continue
 		}
-		gasUsed += msgLookup.Receipt.GasUsed
 
-		tx, err := newEthTxFromMessageLookup(ctx, msgLookup, txIdx, cs, sa)
+		gasUsed += msg.MsgRct.GasUsed
+		tx, err := newEthTxFromMessageLookup(ctx, &api.MsgLookup{
+			Message: msg.MsgCid,
+			Receipt: *msg.MsgRct,
+			TipSet:  ts.Key(),
+			Height:  ts.Height(),
+		}, txIdx, cs, sa)
 		if err != nil {
-			return ethtypes.EthBlock{}, nil
+			return ethtypes.EthBlock{}, xerrors.Errorf("failed to convert msg to ethTx")
 		}
 
 		if fullTxInfo {