internal/ethapi: add transient storage override support for eth_call

core/state/statedb.go

@@ -130,6 +130,8 @@ type StateDB struct {
 
 	// Transient storage
 	transientStorage transientStorage
+	// Overrides to apply after Prepare()
+	pendingTransientOverrides map[common.Address]map[common.Hash]common.Hash
 
 	// Journal of state modifications. This is the backbone of
 	// Snapshot and RevertToSnapshot.
@@ -1430,6 +1432,22 @@ func (s *StateDB) Prepare(rules params.Rules, sender, coinbase common.Address, d
 	}
 	// Reset transient storage at the beginning of transaction execution
 	s.transientStorage = newTransientStorage()
+
+	// Apply any pending transient storage overrides after reset
+	if s.pendingTransientOverrides != nil {
+		for addr, storage := range s.pendingTransientOverrides {
+			for key, value := range storage {
+				s.transientStorage.Set(addr, key, value)
+			}
+		}
+		s.pendingTransientOverrides = nil // Clear after applying
+	}
+}
+
+// SetPendingTransientOverrides stores transient storage overrides to be applied
+// after the next Prepare() call. This ensures overrides are applied to a clean state.
+func (s *StateDB) SetPendingTransientOverrides(overrides map[common.Address]map[common.Hash]common.Hash) {
+	s.pendingTransientOverrides = overrides
 }
 
 // AddAddressToAccessList adds the given address to the access list

ethclient/gethclient/gethclient.go

@@ -167,6 +167,31 @@ func (ec *Client) CallContractWithBlockOverrides(ctx context.Context, msg ethere
 	return hex, err
 }
 
+// CallContractWithTransientOverrides executes a message call transaction, which is directly executed
+// in the VM of the node, but never mined into the blockchain.
+//
+// blockNumber selects the block height at which the call runs. It can be nil, in which
+// case the code is taken from the latest known block. Note that state from very old
+// blocks might not be available.
+//
+// overrides specifies a map of contract states that should be overwritten before executing
+// the message call.
+//
+// blockOverrides specifies block fields exposed to the EVM that can be overridden for the call.
+//
+// transientOverrides specifies transient storage slots that should be overwritten before executing
+// the message call. Transient storage is reset at the beginning of each transaction.
+//
+// Please use ethclient.CallContract instead if you don't need the override functionality.
+func (ec *Client) CallContractWithTransientOverrides(ctx context.Context, msg ethereum.CallMsg, blockNumber *big.Int, overrides *map[common.Address]OverrideAccount, blockOverrides *BlockOverrides, transientOverrides *TransientOverrides) ([]byte, error) {
+	var hex hexutil.Bytes
+	err := ec.c.CallContext(
+		ctx, &hex, "eth_call", toCallArg(msg),
+		toBlockNumArg(blockNumber), overrides, blockOverrides, transientOverrides,
+	)
+	return hex, err
+}
+
 // GCStats retrieves the current garbage collection stats from a geth node.
 func (ec *Client) GCStats(ctx context.Context) (*debug.GCStats, error) {
 	var result debug.GCStats
@@ -348,6 +373,10 @@ type BlockOverrides struct {
 	BaseFee *big.Int
 }
 
+// TransientOverrides specifies transient storage slots to override for eth_call.
+// The map key is the contract address, and the value is another map of slot to value.
+type TransientOverrides map[common.Address]map[common.Hash]common.Hash
+
 func (o BlockOverrides) MarshalJSON() ([]byte, error) {
 	type override struct {
 		Number     *hexutil.Big    `json:"number,omitempty"`

graphql/graphql.go

@@ -1189,7 +1189,7 @@ func (c *CallResult) Status() hexutil.Uint64 {
 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, nil, b.r.backend.RPCEVMTimeout(), b.r.backend.RPCGasCap())
+	result, err := ethapi.DoCall(ctx, b.r.backend, args.Data, *b.numberOrHash, nil, nil, nil, b.r.backend.RPCEVMTimeout(), b.r.backend.RPCGasCap())
 	if err != nil {
 		return nil, err
 	}
@@ -1252,7 +1252,7 @@ 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, nil, p.r.backend.RPCEVMTimeout(), p.r.backend.RPCGasCap())
+	result, err := ethapi.DoCall(ctx, p.r.backend, args.Data, pendingBlockNr, nil, nil, nil, p.r.backend.RPCEVMTimeout(), p.r.backend.RPCGasCap())
 	if err != nil {
 		return nil, err
 	}

internal/ethapi/api.go

@@ -669,7 +669,7 @@ func (context *ChainContext) Config() *params.ChainConfig {
 	return context.b.ChainConfig()
 }
 
-func doCall(ctx context.Context, b Backend, args TransactionArgs, state *state.StateDB, header *types.Header, overrides *override.StateOverride, blockOverrides *override.BlockOverrides, timeout time.Duration, globalGasCap uint64) (*core.ExecutionResult, error) {
+func doCall(ctx context.Context, b Backend, args TransactionArgs, state *state.StateDB, header *types.Header, overrides *override.StateOverride, blockOverrides *override.BlockOverrides, transientOverrides *override.TransientStorageOverride, timeout time.Duration, globalGasCap uint64) (*core.ExecutionResult, error) {
 	blockCtx := core.NewEVMBlockContext(header, NewChainContext(ctx, b), nil)
 	if blockOverrides != nil {
 		if err := blockOverrides.Apply(&blockCtx); err != nil {
@@ -682,6 +682,9 @@ func doCall(ctx context.Context, b Backend, args TransactionArgs, state *state.S
 		return nil, err
 	}
 
+	// Apply transient storage overrides. These will be applied after Prepare() is called.
+	transientOverrides.Apply(state)
+
 	// Setup context so it may be cancelled the call has completed
 	// or, in case of unmetered gas, setup a context with a timeout.
 	var cancel context.CancelFunc
@@ -750,14 +753,14 @@ func applyMessageWithEVM(ctx context.Context, evm *vm.EVM, msg *core.Message, ti
 	return result, nil
 }
 
-func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *override.StateOverride, blockOverrides *override.BlockOverrides, timeout time.Duration, globalGasCap uint64) (*core.ExecutionResult, error) {
+func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash rpc.BlockNumberOrHash, overrides *override.StateOverride, blockOverrides *override.BlockOverrides, transientOverrides *override.TransientStorageOverride, 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)
 	if state == nil || err != nil {
 		return nil, err
 	}
-	return doCall(ctx, b, args, state, header, overrides, blockOverrides, timeout, globalGasCap)
+	return doCall(ctx, b, args, state, header, overrides, blockOverrides, transientOverrides, timeout, globalGasCap)
 }
 
 // Call executes the given transaction on the state for the given block number.
@@ -766,12 +769,12 @@ func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash
 //
 // Note, this function doesn't make and changes in the state/blockchain and is
 // useful to execute and retrieve values.
-func (api *BlockChainAPI) Call(ctx context.Context, args TransactionArgs, blockNrOrHash *rpc.BlockNumberOrHash, overrides *override.StateOverride, blockOverrides *override.BlockOverrides) (hexutil.Bytes, error) {
+func (api *BlockChainAPI) Call(ctx context.Context, args TransactionArgs, blockNrOrHash *rpc.BlockNumberOrHash, overrides *override.StateOverride, blockOverrides *override.BlockOverrides, transientOverrides *override.TransientStorageOverride) (hexutil.Bytes, error) {
 	if blockNrOrHash == nil {
 		latest := rpc.BlockNumberOrHashWithNumber(rpc.LatestBlockNumber)
 		blockNrOrHash = &latest
 	}
-	result, err := DoCall(ctx, api.b, args, *blockNrOrHash, overrides, blockOverrides, api.b.RPCEVMTimeout(), api.b.RPCGasCap())
+	result, err := DoCall(ctx, api.b, args, *blockNrOrHash, overrides, blockOverrides, transientOverrides, api.b.RPCEVMTimeout(), api.b.RPCGasCap())
 	if err != nil {
 		return nil, err
 	}

internal/ethapi/api_test.go

@@ -967,13 +967,14 @@ func TestCall(t *testing.T) {
 	}))
 	randomAccounts := newAccounts(3)
 	var testSuite = []struct {
-		name           string
-		blockNumber    rpc.BlockNumber
-		overrides      override.StateOverride
-		call           TransactionArgs
-		blockOverrides override.BlockOverrides
-		expectErr      error
-		want           string
+		name               string
+		blockNumber        rpc.BlockNumber
+		overrides          override.StateOverride
+		call               TransactionArgs
+		blockOverrides     override.BlockOverrides
+		transientOverrides override.TransientStorageOverride
+		expectErr          error
+		want               string
 	}{
 		// transfer on genesis
 		{
@@ -1226,9 +1227,30 @@ func TestCall(t *testing.T) {
 			},
 			expectErr: errors.New(`block override "withdrawals" is not supported for this RPC method`),
 		},
+		// Test transient storage override
+		{
+			name:        "transient storage override takes effect",
+			blockNumber: rpc.LatestBlockNumber,
+			call: TransactionArgs{
+				From: &accounts[1].addr,
+				To:   &randomAccounts[2].addr,
+			},
+			overrides: override.StateOverride{
+				randomAccounts[2].addr: override.OverrideAccount{
+					// PUSH1 0x00 TLOAD PUSH1 0x00 MSTORE PUSH1 0x20 PUSH1 0x00 RETURN
+					Code: hex2Bytes("0x60005c60005260206000f3"),
+				},
+			},
+			transientOverrides: override.TransientStorageOverride{
+				randomAccounts[2].addr: map[common.Hash]common.Hash{
+					common.Hash{}: common.HexToHash("0xabcd"),
+				},
+			},
+			want: "0x000000000000000000000000000000000000000000000000000000000000abcd",
+		},
 	}
 	for _, tc := range testSuite {
-		result, err := api.Call(context.Background(), tc.call, &rpc.BlockNumberOrHash{BlockNumber: &tc.blockNumber}, &tc.overrides, &tc.blockOverrides)
+		result, err := api.Call(context.Background(), tc.call, &rpc.BlockNumberOrHash{BlockNumber: &tc.blockNumber}, &tc.overrides, &tc.blockOverrides, &tc.transientOverrides)
 		if tc.expectErr != nil {
 			if err == nil {
 				t.Errorf("test %s: want error %v, have nothing", tc.name, tc.expectErr)

internal/ethapi/override/override.go

@@ -33,7 +33,7 @@ import (
 // OverrideAccount indicates the overriding fields of account during the execution
 // of a message call.
 // Note, state and stateDiff can't be specified at the same time. If state is
-// set, message execution will only use the data in the given state. Otherwise
+// set, message execution will only use the data in the given state. Otherwise,
 // if stateDiff is set, all diff will be applied first and then execute the call
 // message.
 type OverrideAccount struct {
@@ -48,6 +48,9 @@ type OverrideAccount struct {
 // StateOverride is the collection of overridden accounts.
 type StateOverride map[common.Address]OverrideAccount
 
+// TransientStorageOverride is the collection of transient storage overrides.
+type TransientStorageOverride map[common.Address]map[common.Hash]common.Hash
+
 func (diff *StateOverride) has(address common.Address) bool {
 	_, ok := (*diff)[address]
 	return ok
@@ -119,6 +122,14 @@ func (diff *StateOverride) Apply(statedb *state.StateDB, precompiles vm.Precompi
 	return nil
 }
 
+// Apply stores transient storage overrides to be applied after Prepare().
+func (diff *TransientStorageOverride) Apply(statedb *state.StateDB) {
+	if diff == nil || len(*diff) == 0 {
+		return
+	}
+	statedb.SetPendingTransientOverrides(*diff)
+}
+
 // BlockOverrides is a set of header fields to override.
 type BlockOverrides struct {
 	Number        *hexutil.Big

internal/ethapi/override/override_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
+	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/triedb"
 )
 
@@ -128,3 +129,56 @@ func hex2Bytes(str string) *hexutil.Bytes {
 	rpcBytes := hexutil.Bytes(common.FromHex(str))
 	return &rpcBytes
 }
+
+func TestStateOverrideTransientStorage(t *testing.T) {
+	db := state.NewDatabase(triedb.NewDatabase(rawdb.NewMemoryDatabase(), nil), nil)
+	statedb, err := state.New(types.EmptyRootHash, db)
+	if err != nil {
+		t.Fatalf("failed to create statedb: %v", err)
+	}
+
+	addr := common.BytesToAddress([]byte{0x1})
+	key1 := common.HexToHash("0x0000000000000000000000000000000000000000000000000000000000000001")
+	key2 := common.HexToHash("0x0000000000000000000000000000000000000000000000000000000000000002")
+	value1 := common.HexToHash("0x1111111111111111111111111111111111111111111111111111111111111111")
+	value2 := common.HexToHash("0x2222222222222222222222222222222222222222222222222222222222222222")
+
+	// Verify initial state is empty
+	if got := statedb.GetTransientState(addr, key1); got != (common.Hash{}) {
+		t.Fatalf("expected initial transient state to be empty, got %s", got.Hex())
+	}
+	if got := statedb.GetTransientState(addr, key2); got != (common.Hash{}) {
+		t.Fatalf("expected initial transient state to be empty, got %s", got.Hex())
+	}
+
+	// Apply transient storage override
+	transientOverride := TransientStorageOverride{
+		addr: map[common.Hash]common.Hash{
+			key1: value1,
+			key2: value2,
+		},
+	}
+
+	transientOverride.Apply(statedb)
+
+	statedb.Prepare(params.Rules{}, common.Address{}, common.Address{}, nil, nil, nil)
+
+	// Verify transient storage was set
+	if got := statedb.GetTransientState(addr, key1); got != value1 {
+		t.Errorf("expected transient state for key1 to be %s, got %s", value1.Hex(), got.Hex())
+	}
+	if got := statedb.GetTransientState(addr, key2); got != value2 {
+		t.Errorf("expected transient state for key2 to be %s, got %s", value2.Hex(), got.Hex())
+	}
+
+	// Verify other addresses/keys remain empty
+	otherAddr := common.BytesToAddress([]byte{0x2})
+	if got := statedb.GetTransientState(otherAddr, key1); got != (common.Hash{}) {
+		t.Errorf("expected transient state for different address to be empty, got %s", got.Hex())
+	}
+
+	otherKey := common.HexToHash("0x0000000000000000000000000000000000000000000000000000000000000003")
+	if got := statedb.GetTransientState(addr, otherKey); got != (common.Hash{}) {
+		t.Errorf("expected transient state for different key to be empty, got %s", got.Hex())
+	}
+}