handle PoA block difficulty during block creation

- in vmState
- in txpool
- in sealing engine

fix #1105

nimbus/p2p/clique/clique_sealer.nim

@@ -12,8 +12,6 @@
 ## Mining Support for Clique PoA Consensus Protocol
 ## ================================================
 ##
-## Note that mining in currently unsupported by `NIMBUS`
-##
 ## For details see
 ## `EIP-225 <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-225.md>`_
 ## and
@@ -322,7 +320,7 @@ proc seal*(c: Clique; ethBlock: var EthBlock):
   ok()
 
 # clique/clique.go(673): func (c *Clique) CalcDifficulty(chain [..]
-proc calcDifficulty(c: Clique;
+proc calcDifficulty*(c: Clique;
                     parent: BlockHeader): Result[DifficultyInt,CliqueError]
                       {.gcsafe, raises: [Defect,CatchableError].} =
   ## For the Consensus Engine, `calcDifficulty()` is the difficulty adjustment

nimbus/sealer.nim

@@ -126,8 +126,6 @@ proc generateBlock(engine: SealingEngineRef,
                    timestamp = getTime(),
                    prevRandao = Hash256()): Result[void, string] =
   # deviation from standard block generator
-  # - no local and remote transactions inclusion(need tx pool)
-  # - no receipts from tx
   # - no DAO hard fork
   # - no local and remote uncles inclusion
 
@@ -188,6 +186,20 @@ proc sealingLoop(engine: SealingEngineRef): Future[void] {.async.} =
 
   clique.authorize(engine.signer, signerFunc)
 
+  proc diffCalculator(timeStamp: EthTime, parent: BlockHeader): DifficultyInt {.gcsafe, raises:[].}  =
+    # pesky Nim effect system
+    try:
+      discard timestamp
+      let rc = clique.calcDifficulty(parent)
+      if rc.isErr:
+        return 0.u256
+      rc.get()
+    except:
+      0.u256
+
+  # switch to PoA difficulty calculator
+  engine.txPool.calcDifficulty = diffCalculator
+
   # convert times.Duration to chronos.Duration
   let period = chronos.seconds(clique.cfg.period.inSeconds)
 

nimbus/utils/tx_pool.nim

@@ -772,6 +772,11 @@ proc `feeRecipient=`*(xp: TxPoolRef; beneficiary: EthAddress) =
   ## a.k.a miner in PoW chain or coinbase
   xp.chain.miner = beneficiary
 
+proc `calcDifficulty=`*(xp: TxPoolRef; val: DifficultyCalculator) =
+  ## Setter, either PoW or PoA difficulty calculator
+  ## PoS difficulty always zero
+  xp.chain.calcDifficulty = val
+
 # ------------------------------------------------------------------------------
 # Public functions, per-tx-item operations
 # ------------------------------------------------------------------------------

nimbus/utils/tx_pool/tx_chain.nim

@@ -20,6 +20,7 @@ import
   ../../forks,
   ../../p2p/executor,
   ../../utils,
+  ../../utils/difficulty,
   ../../vm_state,
   ../../vm_types,
   ./tx_chain/[tx_basefee, tx_gaslimits],
@@ -53,6 +54,8 @@ type
     txRoot: Hash256          ## `rootHash` after packing
     stateRoot: Hash256       ## `stateRoot` after packing
 
+  DifficultyCalculator* = proc(timeStamp: EthTime, parent: BlockHeader): DifficultyInt {.gcsafe, raises:[].}
+
   TxChainRef* = ref object ##\
     ## State cache of the transaction environment for creating a new\
     ## block. This state is typically synchrionised with the canonical\
@@ -69,6 +72,9 @@ type
     # EIP-4399 and EIP-3675
     prevRandao: Hash256      ## PoS block randomness
 
+    # overrideable difficulty calculator
+    calcDifficulty: DifficultyCalculator
+
 # ------------------------------------------------------------------------------
 # Private functions
 # ------------------------------------------------------------------------------
@@ -77,12 +83,16 @@ proc resetTxEnv(dh: TxChainRef; parent: BlockHeader; fee: Option[UInt256])
   {.gcsafe,raises: [Defect,CatchableError].} =
   dh.txEnv.reset
 
+  let timestamp = getTime().utc.toTime
+  # we don't consider PoS difficulty here
+  # because that is handled in vmState
   dh.txEnv.vmState = BaseVMState.new(
     parent    = parent,
-    timestamp = getTime().utc.toTime,
+    timestamp = timestamp,
     gasLimit  = (if dh.maxMode: dh.limits.maxLimit else: dh.limits.trgLimit),
     fee       = fee,
     prevRandao= dh.prevRandao,
+    difficulty= dh.calcDifficulty(timestamp, parent),
     miner     = dh.miner,
     chainDB   = dh.db)
 
@@ -118,6 +128,12 @@ proc new*(T: type TxChainRef; db: BaseChainDB; miner: EthAddress): T
   result.miner = miner
   result.lhwm.lwmTrg = TRG_THRESHOLD_PER_CENT
   result.lhwm.hwmMax = MAX_THRESHOLD_PER_CENT
+  result.calcDifficulty = proc(timeStamp: EthTime, parent: BlockHeader):
+                               DifficultyInt {.gcsafe, raises:[].} =
+    try:
+      db.config.calcDifficulty(timestamp, parent)
+    except:
+      0.u256
   result.update(db.getCanonicalHead)
 
 # ------------------------------------------------------------------------------
@@ -311,6 +327,10 @@ proc `prevRandao=`*(dh: TxChainRef; val: Hash256) =
   ## Setter
   dh.prevRandao = val
 
+proc `calcDifficulty=`*(dh: TxChainRef; val: DifficultyCalculator) =
+  ## Setter
+  dh.calcDifficulty = val
+
 # ------------------------------------------------------------------------------
 # End
 # ------------------------------------------------------------------------------

nimbus/vm/state.nim

@@ -67,6 +67,7 @@ proc init(
       gasLimit:    GasInt;
       fee:         Option[UInt256];
       prevRandao:  Hash256;
+      difficulty:  UInt256;
       miner:       EthAddress;
       chainDB:     BaseChainDB;
       ttdReached:  bool;
@@ -80,6 +81,7 @@ proc init(
   self.gasLimit = gasLimit
   self.fee = fee
   self.prevRandao = prevRandao
+  self.blockDifficulty = difficulty
   self.chainDB = chainDB
   self.ttdReached = ttdReached
   self.tracer = tracer
@@ -96,6 +98,7 @@ proc init(
       gasLimit:    GasInt;
       fee:         Option[UInt256];
       prevRandao:  Hash256;
+      difficulty:  UInt256;
       miner:       EthAddress;
       chainDB:     BaseChainDB;
       tracerFlags: set[TracerFlags])
@@ -109,6 +112,7 @@ proc init(
     gasLimit  = gasLimit,
     fee       = fee,
     prevRandao= prevRandao,
+    difficulty= difficulty,
     miner     = miner,
     chainDB   = chainDB,
     ttdReached= chainDB.isTtdReached(parent.blockHash),
@@ -132,6 +136,7 @@ proc new*(
       gasLimit:    GasInt;          ## tx env: gas limit
       fee:         Option[UInt256]; ## tx env: optional base fee
       prevRandao:  Hash256;         ## tx env: POS block randomness
+      difficulty:  UInt256,         ## tx env: difficulty
       miner:       EthAddress;      ## tx env: coinbase(PoW) or signer(PoA)
       chainDB:     BaseChainDB;     ## block chain database
       tracerFlags: set[TracerFlags] = {};
@@ -152,6 +157,7 @@ proc new*(
     gasLimit    = gasLimit,
     fee         = fee,
     prevRandao  = prevRandao,
+    difficulty  = difficulty,
     miner       = miner,
     chainDB     = chainDB,
     tracerFlags = tracerFlags)
@@ -162,6 +168,7 @@ proc reinit*(self:      BaseVMState;     ## Object descriptor
              gasLimit:  GasInt;          ## tx env: gas limit
              fee:       Option[UInt256]; ## tx env: optional base fee
              prevRandao:Hash256;         ## tx env: POS block randomness
+             difficulty:UInt256,         ## tx env: difficulty
              miner:     EthAddress;      ## tx env: coinbase(PoW) or signer(PoA)
              pruneTrie: bool = true): bool
     {.gcsafe, raises: [Defect,CatchableError].} =
@@ -187,6 +194,7 @@ proc reinit*(self:      BaseVMState;     ## Object descriptor
       gasLimit    = gasLimit,
       fee         = fee,
       prevRandao  = prevRandao,
+      difficulty  = difficulty,
       miner       = miner,
       chainDB     = db,
       ttdReached  = db.isTtdReached(parent.blockHash),
@@ -211,6 +219,7 @@ proc reinit*(self:      BaseVMState; ## Object descriptor
     gasLimit  = header.gasLimit,
     fee       = header.fee,
     prevRandao= header.prevRandao,
+    difficulty= header.difficulty,
     miner     = self.chainDB.getMinerAddress(header),
     pruneTrie = pruneTrie)
 
@@ -249,6 +258,7 @@ proc init*(
     gasLimit    = header.gasLimit,
     fee         = header.fee,
     prevRandao  = header.prevRandao,
+    difficulty  = header.difficulty,
     miner       = chainDB.getMinerAddress(header),
     chainDB     = chainDB,
     tracerFlags = tracerFlags)
@@ -305,12 +315,6 @@ proc setupTxContext*(vmState: BaseVMState, origin: EthAddress, gasPrice: GasInt,
       vmState.chainDB.config.toFork(vmState.parent.blockNumber + 1)
   vmState.gasCosts = vmState.fork.forkToSchedule
 
-proc consensusEnginePoA*(vmState: BaseVMState): bool =
-  # PoA consensus engine have no reward for miner
-  # TODO: this need to be fixed somehow
-  # using `real` engine configuration
-  vmState.chainDB.config.poaEngine
-
 method coinbase*(vmState: BaseVMState): EthAddress {.base, gcsafe.} =
   vmState.minerAddress
 
@@ -324,7 +328,7 @@ method difficulty*(vmState: BaseVMState): UInt256 {.base, gcsafe.} =
     # EIP-4399/EIP-3675
     UInt256.fromBytesBE(vmState.prevRandao.data, allowPadding = false)
   else:
-    vmState.chainDB.config.calcDifficulty(vmState.timestamp, vmState.parent)
+    vmState.blockDifficulty
 
 method baseFee*(vmState: BaseVMState): UInt256 {.base, gcsafe.} =
   if vmState.fee.isSome:

nimbus/vm/types.nim

@@ -39,6 +39,7 @@ type
     gasLimit*      : GasInt
     fee*           : Option[UInt256]
     prevRandao*    : Hash256
+    blockDifficulty*: UInt256
     ttdReached*    : bool
     name*          : string
     flags*         : set[VMFlag]

nimbus/vm2/state.nim

@@ -65,6 +65,7 @@ proc init(
       gasLimit:    GasInt;
       fee:         Option[UInt256];
       prevRandao:  Hash256;
+      difficulty:  UInt256;
       miner:       EthAddress;
       chainDB:     BaseChainDB;
       ttdReached:  bool;
@@ -78,6 +79,7 @@ proc init(
   self.gasLimit = gasLimit
   self.fee = fee
   self.prevRandao = prevRandao
+  self.blockDifficulty = difficulty
   self.chainDB = chainDB
   self.ttdReached = ttdReached
   self.tracer = tracer
@@ -94,6 +96,7 @@ proc init(
       gasLimit:    GasInt;
       fee:         Option[UInt256];
       prevRandao:  Hash256;
+      difficulty:  UInt256;
       miner:       EthAddress;
       chainDB:     BaseChainDB;
       tracerFlags: set[TracerFlags])
@@ -107,6 +110,7 @@ proc init(
     gasLimit  = gasLimit,
     fee       = fee,
     prevRandao= prevRandao,
+    difficulty= difficulty,
     miner     = miner,
     chainDB   = chainDB,
     ttdReached= chainDB.isTtdReached(parent.blockHash),
@@ -130,6 +134,7 @@ proc new*(
       gasLimit:    GasInt;          ## tx env: gas limit
       fee:         Option[UInt256]; ## tx env: optional base fee
       prevRandao:  Hash256;         ## tx env: POS block randomness
+      difficulty:  UInt256,         ## tx env: difficulty
       miner:       EthAddress;      ## tx env: coinbase(PoW) or signer(PoA)
       chainDB:     BaseChainDB;     ## block chain database
       tracerFlags: set[TracerFlags] = {};
@@ -150,6 +155,7 @@ proc new*(
     gasLimit    = gasLimit,
     fee         = fee,
     prevRandao  = prevRandao,
+    difficulty  = difficulty,
     miner       = miner,
     chainDB     = chainDB,
     tracerFlags = tracerFlags)
@@ -160,6 +166,7 @@ proc reinit*(self:      BaseVMState;     ## Object descriptor
              gasLimit:  GasInt;          ## tx env: gas limit
              fee:       Option[UInt256]; ## tx env: optional base fee
              prevRandao:Hash256;         ## tx env: POS block randomness
+             difficulty:UInt256,         ## tx env: difficulty
              miner:     EthAddress;      ## tx env: coinbase(PoW) or signer(PoA)
              pruneTrie: bool = true): bool
     {.gcsafe, raises: [Defect,CatchableError].} =
@@ -185,6 +192,7 @@ proc reinit*(self:      BaseVMState;     ## Object descriptor
       gasLimit    = gasLimit,
       fee         = fee,
       prevRandao  = prevRandao,
+      difficulty  = difficulty,
       miner       = miner,
       chainDB     = db,
       ttdReached  = db.isTtdReached(parent.blockHash),
@@ -209,6 +217,7 @@ proc reinit*(self:      BaseVMState; ## Object descriptor
     gasLimit  = header.gasLimit,
     fee       = header.fee,
     prevRandao= header.prevRandao,
+    difficulty= header.difficulty,
     miner     = self.chainDB.getMinerAddress(header),
     pruneTrie = pruneTrie)
 
@@ -247,6 +256,7 @@ proc init*(
     gasLimit    = header.gasLimit,
     fee         = header.fee,
     prevRandao  = header.prevRandao,
+    difficulty  = header.difficulty,
     miner       = chainDB.getMinerAddress(header),
     chainDB     = chainDB,
     tracerFlags = tracerFlags)
@@ -290,13 +300,6 @@ proc new*(
     tracerFlags = tracerFlags,
     pruneTrie   = pruneTrie)
 
-
-proc consensusEnginePoA*(vmState: BaseVMState): bool =
-  # PoA consensus engine have no reward for miner
-  # TODO: this need to be fixed somehow
-  # using `real` engine configuration
-  vmState.chainDB.config.poaEngine
-
 method coinbase*(vmState: BaseVMState): EthAddress {.base, gcsafe.} =
   vmState.minerAddress
 
@@ -310,7 +313,7 @@ method difficulty*(vmState: BaseVMState): UInt256 {.base, gcsafe.} =
     # EIP-4399/EIP-3675
     UInt256.fromBytesBE(vmState.prevRandao.data, allowPadding = false)
   else:
-    vmState.chainDB.config.calcDifficulty(vmState.timestamp, vmState.parent)
+    vmState.blockDifficulty
 
 method baseFee*(vmState: BaseVMState): UInt256 {.base, gcsafe.} =
   if vmState.fee.isSome:

nimbus/vm2/types.nim

@@ -30,6 +30,7 @@ type
     gasLimit*      : GasInt
     fee*           : Option[UInt256]
     prevRandao*    : Hash256
+    blockDifficulty*: UInt256
     ttdReached*    : bool
     name*          : string
     flags*         : set[VMFlag]

nimbus/vm_state.nim

@@ -26,7 +26,6 @@ export
   vms.blockNumber,
   vms.buildWitness,
   vms.coinbase,
-  vms.consensusEnginePoA,
   vms.difficulty,
   vms.disableTracing,
   vms.enableTracing,