Only cancels transactions if nonce has been incremented since the last estimateGas failure

ethers/contract.nim

@@ -8,6 +8,7 @@ import ./provider
 import ./signer
 import ./events
 import ./fields
+import ./exceptions
 
 export basics
 export provider
@@ -116,6 +117,38 @@ proc call(contract: Contract,
   let response = await contract.provider.call(transaction, overrides)
   return decodeResponse(ReturnType, returnMultiple, response)
 
+proc populateTransaction(
+  contract: Contract,
+  tx: Transaction
+): Future[Transaction] {.async.} =
+
+  if signer =? contract.signer:
+    try:
+      return await signer.populateTransaction(tx)
+    except EstimateGasError as e:
+      if nonce =? e.transaction.nonce:
+
+        if lastSeenNonce =? signer.lastSeenNonce and
+          lastSeenNonce > nonce:
+            discard await signer.cancelTransaction(e.transaction)
+            let revertReason = if not e.parent.isNil: e.parent.msg
+                               else: "unknown"
+            info "A cancellation transaction has been sent to prevent stuck " &
+              "transactions",
+              nonce = e.transaction.nonce,
+              revertReason
+
+        # nonce wasn't incremented by another transaction, so force update the
+        # lastSeenNonce
+        else:
+          signer.updateNonce(nonce - 1, force = true)
+          trace "nonce decremented -- estimateGas failed but no further " &
+            "nonces were generated. Prevents stuck txs.",
+            failedNonce = nonce,
+            newNonce = nonce - 1
+
+      raiseContractError e.msgStack
+
 proc send(contract: Contract,
           function: string,
           parameters: tuple,
@@ -123,7 +156,7 @@ proc send(contract: Contract,
          Future[?TransactionResponse] {.async.} =
   if signer =? contract.signer:
     let transaction = createTransaction(contract, function, parameters, overrides)
-    let populated = await signer.populateTransaction(transaction, cancelOnEstimateGasError = true)
+    let populated = await contract.populateTransaction(transaction)
     let txResp = await signer.sendTransaction(populated)
     return txResp.some
   else:

ethers/exceptions.nim

@@ -0,0 +1,7 @@
+import ./basics
+
+func msgStack*(error: ref EthersError): string =
+  var msg = error.msg
+  if not error.parent.isNil:
+    msg &= " -- Parent exception: " & error.parent.msg
+  return msg

ethers/signer.nim

@@ -66,7 +66,9 @@ method estimateGas*(signer: Signer,
 method getChainId*(signer: Signer): Future[UInt256] {.base, gcsafe.} =
   signer.provider.getChainId()
 
-method getNonce(signer: Signer): Future[UInt256] {.base, gcsafe, async.} =
+func lastSeenNonce*(signer: Signer): ?UInt256 = signer.lastSeenNonce
+
+method getNonce*(signer: Signer): Future[UInt256] {.base, gcsafe, async.} =
   var nonce = await signer.getTransactionCount(BlockTag.pending)
 
   if lastSeen =? signer.lastSeenNonce and lastSeen >= nonce:
@@ -84,7 +86,7 @@ method updateNonce*(
     signer.lastSeenNonce = some nonce
     return
 
-  if nonce > lastSeen:
+  if force or nonce > lastSeen:
     signer.lastSeenNonce = some nonce
 
 method decreaseNonce*(signer: Signer) {.base, gcsafe.} =
@@ -92,8 +94,7 @@ method decreaseNonce*(signer: Signer) {.base, gcsafe.} =
     signer.lastSeenNonce = some lastSeen - 1
 
 method populateTransaction*(signer: Signer,
-                            transaction: Transaction,
-                            cancelOnEstimateGasError = false):
+                            transaction: Transaction):
                            Future[Transaction] {.base, async.} =
 
   if sender =? transaction.sender and sender != await signer.getAddress():

testmodule/testContracts.nim

@@ -16,6 +16,7 @@ type
 
 method mint(token: TestToken, holder: Address, amount: UInt256): ?TransactionResponse {.base, contract.}
 method myBalance(token: TestToken): UInt256 {.base, contract, view.}
+method doRevert(token: TestToken, reason: string): ?TransactionResponse {.base, contract.}
 
 for url in ["ws://localhost:8545", "http://localhost:8545"]:
 

testnode/contracts/TestToken.sol

@@ -21,4 +21,9 @@ contract TestToken is ERC20 {
   function myBalance() public view returns (uint256)  {
     return balanceOf(msg.sender);
   }
+
+  function doRevert(string memory reason) public {
+    // Revert every tx with given reason
+    require(false, reason);
+  }
 }