Support fetching pending nonce

CHANGELOG.md

@@ -60,6 +60,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (evm) [tharsis#24](https://github.com/tharsis/ethermint/pull/24) Implement metrics for `MsgEthereumTx`, state transitions, `BeginBlock` and `EndBlock`.
 * (rpc) [#124](https://github.com/tharsis/ethermint/issues/124) Implement `txpool_content`, `txpool_inspect` and `txpool_status` RPC methods
 * (rpc) [tharsis#112](https://github.com/tharsis/ethermint/pull/153) Fix `eth_coinbase` to return the ethereum address of the validator
+* (rpc) [tharsis#176](https://github.com/tharsis/ethermint/issues/176) Support fetching pending nonce
 
 ### Bug Fixes
 

ethereum/rpc/namespaces/eth/api.go

@@ -256,7 +256,8 @@ func (e *PublicAPI) GetTransactionCount(address common.Address, blockNum rpctype
  return &n, nil
  }
 
- _, nonce, err := accRet.GetAccountNumberSequence(e.clientCtx, from)
+ includePending := blockNum == rpctypes.EthPendingBlockNumber
+ nonce, err := getAccountNonce(e.clientCtx, e.backend, address, includePending, e.logger)
  if err != nil {
  return nil, err
  }
@@ -565,16 +566,12 @@ func (e *PublicAPI) doCall(
  accessList = args.AccessList
  }
 
- // Set destination address for call
- var fromAddr sdk.AccAddress
- if args.From != nil {
- fromAddr = sdk.AccAddress(args.From.Bytes())
- } else {
- fromAddr = sdk.AccAddress(common.Address{}.Bytes())
+ if args.From == nil {
  args.From = &common.Address{}
  }
 
- _, seq, err := e.clientCtx.AccountRetriever.GetAccountNumberSequence(e.clientCtx, fromAddr)
+ includePending := blockNr == rpctypes.EthPendingBlockNumber
+ seq, err := getAccountNonce(e.clientCtx, e.backend, *args.From, includePending, e.logger)
  if err != nil {
  return nil, err
  }
@@ -1018,9 +1015,6 @@ func (e *PublicAPI) GetProof(address common.Address, storageKeys []string, block
 // provided on the args
 func (e *PublicAPI) setTxDefaults(args rpctypes.SendTxArgs) (rpctypes.SendTxArgs, error) {
 
- // Get nonce (sequence) from sender account
- from := sdk.AccAddress(args.From.Bytes())
-
  if args.GasPrice == nil {
  // TODO: Change to either:
  // - min gas price from context once available through server/daemon, or
@@ -1031,7 +1025,7 @@ func (e *PublicAPI) setTxDefaults(args rpctypes.SendTxArgs) (rpctypes.SendTxArgs
  if args.Nonce == nil {
  // get the nonce from the account retriever
  // ignore error in case tge account doesn't exist yet
- _, nonce, _ := e.clientCtx.AccountRetriever.GetAccountNumberSequence(e.clientCtx, from)
+ nonce, _ := getAccountNonce(e.clientCtx, e.backend, args.From, true, e.logger)
  args.Nonce = (*hexutil.Uint64)(&nonce)
  }
 
@@ -1084,3 +1078,40 @@ func (e *PublicAPI) setTxDefaults(args rpctypes.SendTxArgs) (rpctypes.SendTxArgs
 
  return args, nil
 }
+
+// getAccountNonce returns the account nonce for the given account address.
+// If the pending value is true, it will iterate over the mempool (pending)
+// txs in order to compute and return the pending tx sequence.
+// Todo: include the ability to specify a blockNumber
+func getAccountNonce(ctx client.Context, backend backend.Backend, accAddr common.Address, pending bool, logger log.Logger) (uint64, error) {
+ _, nonce, err := ctx.AccountRetriever.GetAccountNumberSequence(ctx, accAddr.Bytes())
+ if err != nil {
+ return 0, err
+ }
+
+ if !pending {
+ return nonce, nil
+ }
+
+ // the account retriever doesn't include the uncommitted transactions on the nonce so we need to
+ // to manually add them.
+ pendingTxs, err := backend.PendingTransactions()
+ if err != nil {
+ logger.Errorln("fails to fetch pending transactions")
+ return nonce, nil
+ }
+
+ // add the uncommitted txs to the nonce counter
+ if len(pendingTxs) != 0 {
+ for i := range pendingTxs {
+ if pendingTxs[i] == nil {
+ continue
+ }
+ if pendingTxs[i].From == accAddr {
+ nonce++
+ }
+ }
+ }
+
+ return nonce, nil
+}