On transaction failure, fetch revert reason with replayed transaction (#57)

When transaction fails (receipt.status is Failed), fetch revert reason by replaying transaction.

Author: emizzle

ethers.nimble

@@ -4,6 +4,7 @@ description = "library for interacting with Ethereum"
 license = "MIT"
 
 requires "nim >= 1.6.0"
+requires "chronicles >= 0.10.3 & < 0.11.0"
 requires "chronos >= 3.0.0 & < 4.0.0"
 requires "contractabi >= 0.6.0 & < 0.7.0"
 requires "questionable >= 0.10.2 & < 0.11.0"

ethers/contract.nim

@@ -1,6 +1,7 @@
 import std/json
 import std/macros
 import std/sequtils
+import pkg/chronicles
 import pkg/chronos
 import pkg/contractabi
 import ./basics
@@ -13,6 +14,9 @@ export basics
 export provider
 export events
 
+logScope:
+  topics = "ethers contract"
+
 type
   Contract* = ref object of RootObj
     provider: Provider

ethers/provider.nim

@@ -1,3 +1,5 @@
+import pkg/chronicles
+import pkg/stew/byteutils
 import ./basics
 import ./transaction
 import ./blocktag
@@ -47,18 +49,53 @@ type
     logs*: seq[Log]
     blockNumber*: ?UInt256
     cumulativeGasUsed*: UInt256
+    effectiveGasPrice*: ?UInt256
     status*: TransactionStatus
+    transactionType*: TransactionType
   LogHandler* = proc(log: Log) {.gcsafe, upraises:[].}
   BlockHandler* = proc(blck: Block) {.gcsafe, upraises:[].}
   Topic* = array[32, byte]
   Block* = object
     number*: ?UInt256
     timestamp*: UInt256
     hash*: ?BlockHash
+  PastTransaction* = object
+    blockHash*: BlockHash
+    blockNumber*: UInt256
+    sender*: Address
+    gas*: UInt256
+    gasPrice*: UInt256
+    hash*: TransactionHash
+    input*: seq[byte]
+    nonce*: UInt256
+    to*: Address
+    transactionIndex*: UInt256
+    transactionType*: ?TransactionType
+    chainId*: ?UInt256
+    value*: UInt256
+    v*, r*, s*: UInt256
 
 const EthersDefaultConfirmations* {.intdefine.} = 12
 const EthersReceiptTimeoutBlks* {.intdefine.} = 50 # in blocks
 
+logScope:
+  topics = "ethers provider"
+
+template raiseProviderError(msg: string) =
+  raise newException(ProviderError, msg)
+
+func toTransaction*(past: PastTransaction): Transaction =
+  Transaction(
+    sender: some past.sender,
+    gasPrice: some past.gasPrice,
+    data: past.input,
+    nonce: some past.nonce,
+    to: past.to,
+    transactionType: past.transactionType,
+    gasLimit: some past.gas,
+    chainId: past.chainId
+  )
+
 method getBlockNumber*(provider: Provider): Future[UInt256] {.base, gcsafe.} =
   doAssert false, "not implemented"
 
@@ -79,6 +116,11 @@ method getTransactionCount*(provider: Provider,
                            Future[UInt256] {.base, gcsafe.} =
   doAssert false, "not implemented"
 
+method getTransaction*(provider: Provider,
+                       txHash: TransactionHash):
+                      Future[?PastTransaction] {.base, gcsafe.} =
+  doAssert false, "not implemented"
+
 method getTransactionReceipt*(provider: Provider,
                             txHash: TransactionHash):
                            Future[?TransactionReceipt] {.base, gcsafe.} =
@@ -94,7 +136,8 @@ method getLogs*(provider: Provider,
   doAssert false, "not implemented"
 
 method estimateGas*(provider: Provider,
-                    transaction: Transaction): Future[UInt256] {.base, gcsafe.} =
+                    transaction: Transaction,
+                    blockTag = BlockTag.latest): Future[UInt256] {.base, gcsafe.} =
   doAssert false, "not implemented"
 
 method getChainId*(provider: Provider): Future[UInt256] {.base, gcsafe.} =
@@ -114,11 +157,73 @@ method subscribe*(provider: Provider,
 method unsubscribe*(subscription: Subscription) {.base, async.} =
   doAssert false, "not implemented"
 
+proc replay*(provider: Provider, tx: Transaction, blockNumber: UInt256) {.async.} =
+  # Replay transaction at block. Useful for fetching revert reasons, which will
+  # be present in the raised error message. The replayed block number should
+  # include the state of the chain in the block previous to the block in which
+  # the transaction was mined. This means that transactions that were mined in
+  # the same block BEFORE this transaction will not have their state transitions
+  # included in the replay.
+  # More information: https://snakecharmers.ethereum.org/web3py-revert-reason-parsing/
+  trace "replaying transaction", gasLimit = tx.gasLimit, tx = $tx
+  discard await provider.call(tx, BlockTag.init(blockNumber))
+
+method getRevertReason*(
+  provider: Provider,
+  hash: TransactionHash,
+  blockNumber: UInt256
+): Future[?string] {.base, async.} =
+
+  without pastTx =? await provider.getTransaction(hash):
+    return none string
+
+  try:
+    await provider.replay(pastTx.toTransaction, blockNumber)
+    return none string
+  except ProviderError as e:
+    # should contain the revert reason
+    return some e.msg
+
+method getRevertReason*(
+  provider: Provider,
+  receipt: TransactionReceipt
+): Future[?string] {.base, async.} =
+
+  if receipt.status != TransactionStatus.Failure:
+    return none string
+
+  without blockNumber =? receipt.blockNumber:
+    return none string
+
+  return await provider.getRevertReason(receipt.transactionHash, blockNumber - 1)
+
+proc ensureSuccess(
+  provider: Provider,
+  receipt: TransactionReceipt
+) {.async, upraises: [ProviderError].} =
+  ## If the receipt.status is Failed, the tx is replayed to obtain a revert
+  ## reason, after which a ProviderError with the revert reason is raised.
+  ## If no revert reason was obtained
+
+  # TODO: handle TransactionStatus.Invalid?
+  if receipt.status == TransactionStatus.Failure:
+    logScope:
+      transactionHash = receipt.transactionHash.to0xHex
+
+    trace "transaction failed, replaying transaction to get revert reason"
+
+    if revertReason =? await provider.getRevertReason(receipt):
+      trace "transaction revert reason obtained", revertReason
+      raiseProviderError(revertReason)
+    else:
+      trace "transaction replay completed, no revert reason obtained"
+      raiseProviderError("Transaction reverted with unknown reason")
+
 proc confirm*(tx: TransactionResponse,
               confirmations = EthersDefaultConfirmations,
               timeout = EthersReceiptTimeoutBlks):
              Future[TransactionReceipt]
-             {.async, upraises: [EthersError].} =
+             {.async, upraises: [ProviderError, EthersError].} =
   ## Waits for a transaction to be mined and for the specified number of blocks
   ## to pass since it was mined (confirmations).
   ## A timeout, in blocks, can be specified that will raise an error if too many
@@ -157,6 +262,7 @@ proc confirm*(tx: TransactionResponse,
 
     if txBlockNumber + confirmations.u256 <= blockNumber + 1:
       await subscription.unsubscribe()
+      await tx.provider.ensureSuccess(receipt)
       return receipt
 
 proc confirm*(tx: Future[TransactionResponse],

ethers/providers/jsonrpc.nim

@@ -1,6 +1,8 @@
 import std/json
 import std/tables
 import std/uri
+import pkg/chronicles
+import pkg/eth/common/eth_types_json_serialization
 import pkg/json_rpc/rpcclient
 import pkg/json_rpc/errors
 import ../basics
@@ -13,9 +15,13 @@ import ./jsonrpc/subscriptions
 export json
 export basics
 export provider
+export chronicles
 
 push: {.upraises: [].}
 
+logScope:
+  topics = "ethers jsonrpc"
+
 type
   JsonRpcProvider* = ref object of Provider
     client: Future[RpcClient]
@@ -137,6 +143,13 @@ method getTransactionCount*(provider: JsonRpcProvider,
     let client = await provider.client
     return await client.eth_getTransactionCount(address, blockTag)
 
+method getTransaction*(provider: JsonRpcProvider,
+                       txHash: TransactionHash):
+                      Future[?PastTransaction] {.async.} =
+  convertError:
+    let client = await provider.client
+    return await client.eth_getTransactionByHash(txHash)
+
 method getTransactionReceipt*(provider: JsonRpcProvider,
                               txHash: TransactionHash):
                              Future[?TransactionReceipt] {.async.} =
@@ -164,10 +177,11 @@ method getLogs*(provider: JsonRpcProvider,
     return logs
 
 method estimateGas*(provider: JsonRpcProvider,
-                    transaction: Transaction): Future[UInt256] {.async.} =
+                    transaction: Transaction,
+                    blockTag = BlockTag.latest): Future[UInt256] {.async.} =
   convertError:
     let client = await provider.client
-    return await client.eth_estimateGas(transaction)
+    return await client.eth_estimateGas(transaction, blockTag)
 
 method getChainId*(provider: JsonRpcProvider): Future[UInt256] {.async.} =
   convertError:

ethers/providers/jsonrpc/conversions.nim

@@ -1,4 +1,5 @@
 import std/json
+import std/strformat
 import std/strutils
 import pkg/json_rpc/jsonmarshal
 import pkg/stew/byteutils
@@ -9,6 +10,16 @@ import ../../provider
 
 export jsonmarshal
 
+type JsonSerializationError = object of EthersError
+
+template raiseSerializationError(message: string) =
+  raise newException(JsonSerializationError, message)
+
+proc expectFields(json: JsonNode, expectedFields: varargs[string]) =
+  for fieldName in expectedFields:
+    if not json.hasKey(fieldName):
+      raiseSerializationError(fmt"'{fieldName}' field not found in ${json}")
+
 func fromJson*(T: type, json: JsonNode, name = ""): T =
   fromJson(json, name, result)
 
@@ -47,6 +58,15 @@ func `%`*(integer: UInt256): JsonNode =
 func fromJson*(json: JsonNode, name: string, result: var UInt256) =
   result = UInt256.fromHex(json.getStr())
 
+# TransactionType
+
+func fromJson*(json: JsonNode, name: string, result: var TransactionType) =
+  let val = fromHex[int](json.getStr)
+  result = TransactionType(val)
+
+func `%`*(txType: TransactionType): JsonNode =
+  %("0x" & txType.int.toHex(1))
+
 # Transaction
 
 func `%`*(transaction: Transaction): JsonNode =
@@ -70,6 +90,9 @@ func `%`*(blockTag: BlockTag): JsonNode =
 # Log
 
 func fromJson*(json: JsonNode, name: string, result: var Log) =
+  if not (json.hasKey("data") and json.hasKey("topics")):
+    raise newException(ValueError, "'data' and/or 'topics' fields not found")
+
   var data: seq[byte]
   var topics: seq[Topic]
   fromJson(json["data"], "data", data)
@@ -83,4 +106,83 @@ func fromJson*(json: JsonNode, name: string, result: var TransactionStatus) =
   result = TransactionStatus(val)
 
 func `%`*(status: TransactionStatus): JsonNode =
-  %(status.int.toHex)
+  %("0x" & status.int.toHex(1))
+
+# PastTransaction
+
+func fromJson*(json: JsonNode, name: string, result: var PastTransaction) =
+  # Deserializes a past transaction, eg eth_getTransactionByHash.
+  # Spec: https://ethereum.org/en/developers/docs/apis/json-rpc/#eth_gettransactionbyhash
+  json.expectFields "blockHash", "blockNumber", "from", "gas", "gasPrice",
+                    "hash", "input", "nonce", "to", "transactionIndex", "value",
+                    "v", "r", "s"
+
+  result = PastTransaction(
+    blockHash: BlockHash.fromJson(json["blockHash"], "blockHash"),
+    blockNumber: UInt256.fromJson(json["blockNumber"], "blockNumber"),
+    sender: Address.fromJson(json["from"], "from"),
+    gas: UInt256.fromJson(json["gas"], "gas"),
+    gasPrice: UInt256.fromJson(json["gasPrice"], "gasPrice"),
+    hash: TransactionHash.fromJson(json["hash"], "hash"),
+    input: seq[byte].fromJson(json["input"], "input"),
+    nonce: UInt256.fromJson(json["nonce"], "nonce"),
+    to: Address.fromJson(json["to"], "to"),
+    transactionIndex: UInt256.fromJson(json["transactionIndex"], "transactionIndex"),
+    value: UInt256.fromJson(json["value"], "value"),
+    v: UInt256.fromJson(json["v"], "v"),
+    r: UInt256.fromJson(json["r"], "r"),
+    s: UInt256.fromJson(json["s"], "s"),
+  )
+  if json.hasKey("type"):
+    result.transactionType = fromJson(?TransactionType, json["type"], "type")
+  if json.hasKey("chainId"):
+    result.chainId = fromJson(?UInt256, json["chainId"], "chainId")
+
+func `%`*(tx: PastTransaction): JsonNode =
+  let json = %*{
+    "blockHash": tx.blockHash,
+    "blockNumber": tx.blockNumber,
+    "from": tx.sender,
+    "gas": tx.gas,
+    "gasPrice": tx.gasPrice,
+    "hash": tx.hash,
+    "input": tx.input,
+    "nonce": tx.nonce,
+    "to": tx.to,
+    "transactionIndex": tx.transactionIndex,
+    "value": tx.value,
+    "v": tx.v,
+    "r": tx.r,
+    "s": tx.s
+  }
+  if txType =? tx.transactionType:
+    json["type"] = %txType
+  if chainId =? tx.chainId:
+    json["chainId"] = %chainId
+  return json
+
+# TransactionReceipt
+
+func fromJson*(json: JsonNode, name: string, result: var TransactionReceipt) =
+  # Deserializes a transaction receipt, eg eth_getTransactionReceipt.
+  # Spec: https://ethereum.org/en/developers/docs/apis/json-rpc/#eth_gettransactionreceipt
+  json.expectFields "transactionHash", "transactionIndex", "cumulativeGasUsed",
+                    "effectiveGasPrice", "gasUsed", "logs", "logsBloom", "type",
+                    "status"
+
+  result = TransactionReceipt(
+    transactionHash: fromJson(TransactionHash, json["transactionHash"], "transactionHash"),
+    transactionIndex: UInt256.fromJson(json["transactionIndex"], "transactionIndex"),
+    blockHash: fromJson(?BlockHash, json["blockHash"], "blockHash"),
+    blockNumber: fromJson(?UInt256, json["blockNumber"], "blockNumber"),
+    sender: fromJson(?Address, json["from"], "from"),
+    to: fromJson(?Address, json["to"], "to"),
+    cumulativeGasUsed: UInt256.fromJson(json["cumulativeGasUsed"], "cumulativeGasUsed"),
+    effectiveGasPrice: fromJson(?UInt256, json["effectiveGasPrice"], "effectiveGasPrice"),
+    gasUsed: UInt256.fromJson(json["gasUsed"], "gasUsed"),
+    contractAddress: fromJson(?Address, json["contractAddress"], "contractAddress"),
+    logs: seq[Log].fromJson(json["logs"], "logs"),
+    logsBloom: seq[byte].fromJson(json["logsBloom"], "logsBloom"),
+    transactionType: TransactionType.fromJson(json["type"], "type"),
+    status: TransactionStatus.fromJson(json["status"], "status")
+  )

ethers/providers/jsonrpc/signatures.nim

@@ -5,9 +5,10 @@ proc eth_call(transaction: Transaction, blockTag: BlockTag): seq[byte]
 proc eth_gasPrice(): UInt256
 proc eth_getBlockByNumber(blockTag: BlockTag, includeTransactions: bool): ?Block
 proc eth_getLogs(filter: EventFilter | Filter | FilterByBlockHash): JsonNode
+proc eth_getTransactionByHash(hash: TransactionHash): ?PastTransaction
 proc eth_getBlockByHash(hash: BlockHash, includeTransactions: bool): ?Block
 proc eth_getTransactionCount(address: Address, blockTag: BlockTag): UInt256
-proc eth_estimateGas(transaction: Transaction): UInt256
+proc eth_estimateGas(transaction: Transaction, blockTag: BlockTag): UInt256
 proc eth_chainId(): UInt256
 proc eth_sendTransaction(transaction: Transaction): TransactionHash
 proc eth_sendRawTransaction(data: seq[byte]): TransactionHash