Merge pull request #286 from OffchainLabs/update-pendingblk-blkctxtime

Update blockContext's time field for pending blocks to match current time. Enable eth_estimateGas and eth_call rpcs to utilize this

internal/ethapi/api.go

@@ -1165,13 +1165,28 @@ func doCall(ctx context.Context, b Backend, args TransactionArgs, state *state.S
 	return result, nil
 }
 
+func updateHeaderForPendingBlocks(blockNrOrHash rpc.BlockNumberOrHash, header *types.Header) *types.Header {
+	if blockNrOrHash.BlockNumber != nil &&
+		*blockNrOrHash.BlockNumber == rpc.PendingBlockNumber {
+		headerCopy := *header
+		now := uint64(time.Now().Unix())
+		if now > headerCopy.Time {
+			headerCopy.Time = now
+		}
+		headerCopy.Number = new(big.Int).Add(headerCopy.Number, common.Big1)
+		return &headerCopy
+	}
+	return header
+}
+
 func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *StateOverride, blockOverrides *BlockOverrides, timeout time.Duration, globalGasCap uint64, runMode core.MessageRunMode) (*core.ExecutionResult, error) {
 	defer func(start time.Time) { log.Debug("Executing EVM call finished", "runtime", time.Since(start)) }(time.Now())
 
 	state, header, err := b.StateAndHeaderByNumberOrHash(ctx, blockNrOrHash)
 	if state == nil || err != nil {
 		return nil, err
 	}
+	header = updateHeaderForPendingBlocks(blockNrOrHash, header)
 
 	return doCall(ctx, b, args, state, header, overrides, blockOverrides, timeout, globalGasCap, runMode)
 }
@@ -1303,6 +1318,7 @@ func DoEstimateGas(ctx context.Context, b Backend, args TransactionArgs, blockNr
 	if err := overrides.Apply(state); err != nil {
 		return 0, err
 	}
+	header = updateHeaderForPendingBlocks(blockNrOrHash, header)
 
 	// Recap the highest gas limit with account's available balance.
 	if feeCap.BitLen() != 0 {
@@ -1399,7 +1415,7 @@ func DoEstimateGas(ctx context.Context, b Backend, args TransactionArgs, blockNr
 // value is capped by both `args.Gas` (if non-nil & non-zero) and the backend's RPCGasCap
 // configuration (if non-zero).
 func (s *BlockChainAPI) EstimateGas(ctx context.Context, args TransactionArgs, blockNrOrHash *rpc.BlockNumberOrHash, overrides *StateOverride) (hexutil.Uint64, error) {
-	bNrOrHash := rpc.BlockNumberOrHashWithNumber(rpc.LatestBlockNumber)
+	bNrOrHash := rpc.BlockNumberOrHashWithNumber(rpc.PendingBlockNumber)
 	if blockNrOrHash != nil {
 		bNrOrHash = *blockNrOrHash
 	}