internal/ethapi: add block overrides to eth_call

Author: s1na

eth/api_backend.go

@@ -240,12 +240,15 @@ func (b *EthAPIBackend) GetTd(ctx context.Context, hash common.Hash) *big.Int {
 	return nil
 }
 
-func (b *EthAPIBackend) GetEVM(ctx context.Context, msg *core.Message, state *state.StateDB, header *types.Header, vmConfig *vm.Config) (*vm.EVM, func() error, error) {
+func (b *EthAPIBackend) GetEVM(ctx context.Context, msg *core.Message, state *state.StateDB, header *types.Header, vmConfig *vm.Config, blockCtx *vm.BlockContext) (*vm.EVM, func() error, error) {
 	if vmConfig == nil {
 		vmConfig = b.eth.blockchain.GetVMConfig()
 	}
 	txContext := core.NewEVMTxContext(msg)
 	context := core.NewEVMBlockContext(header, b.eth.BlockChain(), nil)
+	if blockCtx != nil {
+		context = *blockCtx
+	}
 	return vm.NewEVM(context, txContext, state, b.eth.blockchain.Config(), *vmConfig), state.Error, nil
 }
 

eth/tracers/api.go

@@ -100,34 +100,10 @@ func NewAPI(backend Backend) *API {
 	return &API{backend: backend}
 }
 
-type chainContext struct {
-	api *API
-	ctx context.Context
-}
-
-func (context *chainContext) Engine() consensus.Engine {
-	return context.api.backend.Engine()
-}
-
-func (context *chainContext) GetHeader(hash common.Hash, number uint64) *types.Header {
-	header, err := context.api.backend.HeaderByNumber(context.ctx, rpc.BlockNumber(number))
-	if err != nil {
-		return nil
-	}
-	if header.Hash() == hash {
-		return header
-	}
-	header, err = context.api.backend.HeaderByHash(context.ctx, hash)
-	if err != nil {
-		return nil
-	}
-	return header
-}
-
 // chainContext constructs the context reader which is used by the evm for reading
 // the necessary chain context.
 func (api *API) chainContext(ctx context.Context) core.ChainContext {
-	return &chainContext{api: api, ctx: ctx}
+	return ethapi.NewChainContext(ctx, api.backend)
 }
 
 // blockByNumber is the wrapper of the chain access function offered by the backend.

graphql/graphql.go

@@ -1067,7 +1067,7 @@ func (c *CallResult) Status() Long {
 func (b *Block) Call(ctx context.Context, args struct {
 	Data ethapi.TransactionArgs
 }) (*CallResult, error) {
-	result, err := ethapi.DoCall(ctx, b.r.backend, args.Data, *b.numberOrHash, nil, b.r.backend.RPCEVMTimeout(), b.r.backend.RPCGasCap())
+	result, err := ethapi.DoCall(ctx, b.r.backend, args.Data, *b.numberOrHash, nil, nil, b.r.backend.RPCEVMTimeout(), b.r.backend.RPCGasCap())
 	if err != nil {
 		return nil, err
 	}
@@ -1131,7 +1131,7 @@ func (p *Pending) Call(ctx context.Context, args struct {
 	Data ethapi.TransactionArgs
 }) (*CallResult, error) {
 	pendingBlockNr := rpc.BlockNumberOrHashWithNumber(rpc.PendingBlockNumber)
-	result, err := ethapi.DoCall(ctx, p.r.backend, args.Data, pendingBlockNr, nil, p.r.backend.RPCEVMTimeout(), p.r.backend.RPCGasCap())
+	result, err := ethapi.DoCall(ctx, p.r.backend, args.Data, pendingBlockNr, nil, nil, p.r.backend.RPCEVMTimeout(), p.r.backend.RPCGasCap())
 	if err != nil {
 		return nil, err
 	}

internal/ethapi/api.go

@@ -33,6 +33,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/consensus/misc"
 	"github.com/ethereum/go-ethereum/core"
@@ -955,7 +956,39 @@ func (diff *BlockOverrides) Apply(blockCtx *vm.BlockContext) {
 	}
 }
 
-func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *StateOverride, timeout time.Duration, globalGasCap uint64) (*core.ExecutionResult, error) {
+// ChainContextBackend provides methods required to implement ChainContext.
+type ChainContextBackend interface {
+	Engine() consensus.Engine
+	HeaderByNumber(context.Context, rpc.BlockNumber) (*types.Header, error)
+}
+
+// ChainContext is an implementation of core.ChainContext. It's main use-case
+// is instantiating a vm.BlockContext without having access to the BlockChain object.
+type ChainContext struct {
+	b   ChainContextBackend
+	ctx context.Context
+}
+
+// NewChainContext creates a new ChainContext object.
+func NewChainContext(ctx context.Context, backend ChainContextBackend) *ChainContext {
+	return &ChainContext{ctx: ctx, b: backend}
+}
+
+func (context *ChainContext) Engine() consensus.Engine {
+	return context.b.Engine()
+}
+
+func (context *ChainContext) GetHeader(hash common.Hash, number uint64) *types.Header {
+	// This method is called to get the hash for a block number when executing the BLOCKHASH
+	// opcode. Hence no need to search for non-canonical blocks.
+	header, err := context.b.HeaderByNumber(context.ctx, rpc.BlockNumber(number))
+	if err != nil || header.Hash() != hash {
+		return nil
+	}
+	return header
+}
+
+func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *StateOverride, blockOverrides *BlockOverrides, timeout time.Duration, globalGasCap uint64) (*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)
@@ -982,7 +1015,11 @@ func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash
 	if err != nil {
 		return nil, err
 	}
-	evm, vmError, err := b.GetEVM(ctx, msg, state, header, &vm.Config{NoBaseFee: true})
+	blockCtx := core.NewEVMBlockContext(header, NewChainContext(ctx, b), nil)
+	if blockOverrides != nil {
+		blockOverrides.Apply(&blockCtx)
+	}
+	evm, vmError, err := b.GetEVM(ctx, msg, state, header, &vm.Config{NoBaseFee: true}, &blockCtx)
 	if err != nil {
 		return nil, err
 	}
@@ -1040,14 +1077,18 @@ func (e *revertError) ErrorData() interface{} {
 	return e.reason
 }
 
+type callConfig struct {
+	BlockOverrides *BlockOverrides
+}
+
 // Call executes the given transaction on the state for the given block number.
 //
 // Additionally, the caller can specify a batch of contract for fields overriding.
 //
 // Note, this function doesn't make and changes in the state/blockchain and is
 // useful to execute and retrieve values.
-func (s *BlockChainAPI) Call(ctx context.Context, args TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *StateOverride) (hexutil.Bytes, error) {
-	result, err := DoCall(ctx, s.b, args, blockNrOrHash, overrides, s.b.RPCEVMTimeout(), s.b.RPCGasCap())
+func (s *BlockChainAPI) Call(ctx context.Context, args TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *StateOverride, blockOverrides *BlockOverrides) (hexutil.Bytes, error) {
+	result, err := DoCall(ctx, s.b, args, blockNrOrHash, overrides, blockOverrides, s.b.RPCEVMTimeout(), s.b.RPCGasCap())
 	if err != nil {
 		return nil, err
 	}
@@ -1132,7 +1173,7 @@ func DoEstimateGas(ctx context.Context, b Backend, args TransactionArgs, blockNr
 	executable := func(gas uint64) (bool, *core.ExecutionResult, error) {
 		args.Gas = (*hexutil.Uint64)(&gas)
 
-		result, err := DoCall(ctx, b, args, blockNrOrHash, nil, 0, gasCap)
+		result, err := DoCall(ctx, b, args, blockNrOrHash, nil, nil, 0, gasCap)
 		if err != nil {
 			if errors.Is(err, core.ErrIntrinsicGas) {
 				return true, nil, nil // Special case, raise gas limit
@@ -1474,7 +1515,7 @@ func AccessList(ctx context.Context, b Backend, blockNrOrHash rpc.BlockNumberOrH
 		// Apply the transaction with the access list tracer
 		tracer := logger.NewAccessListTracer(accessList, args.from(), to, precompiles)
 		config := vm.Config{Tracer: tracer, NoBaseFee: true}
-		vmenv, _, err := b.GetEVM(ctx, msg, statedb, header, &config)
+		vmenv, _, err := b.GetEVM(ctx, msg, statedb, header, &config, nil)
 		if err != nil {
 			return nil, 0, nil, err
 		}