core, core/types: plain Message struct (#25977)

Here, the core.Message interface turns into a plain struct and
types.Message gets removed.

This is a breaking change to packages core and core/types. While we do
not promise API stability for package core, we do for core/types. An
exception can be made for types.Message, since it doesn't have any
purpose apart from invoking the state transition in package core.
types.Message was also marked deprecated by the same commit it
got added in, 4dca5d4db7 (November 2016).

The core.Message interface was added in December 2014, in commit
db494170dc, for the purpose of 'testing' state transitions. It's the
same change that made transaction struct fields private. Before that,
the state transition used *types.Transaction directly.

Over time, multiple implementations of the interface accrued across
different packages, since constructing a Message is required whenever
one wants to invoke the state transition. These implementations all
looked very similar, a struct with private fields exposing the fields
as accessor methods.

By changing Message into a struct with public fields we can remove all
these useless interface implementations. It will also hopefully
simplify future changes to the type with less updates to apply across
all of go-ethereum when a field is added to Message.

---------

Co-authored-by: Felix Lange <fjl@twurst.com>

internal/ethapi/api.go

@@ -1005,7 +1005,7 @@ func DoCall(ctx context.Context, b Backend, args TransactionArgs, blockNrOrHash
 		return nil, fmt.Errorf("execution aborted (timeout = %v)", timeout)
 	}
 	if err != nil {
-		return result, fmt.Errorf("err: %w (supplied gas %d)", err, msg.Gas())
+		return result, fmt.Errorf("err: %w (supplied gas %d)", err, msg.GasLimit)
 	}
 	return result, nil
 }
@@ -1478,7 +1478,7 @@ func AccessList(ctx context.Context, b Backend, blockNrOrHash rpc.BlockNumberOrH
 		if err != nil {
 			return nil, 0, nil, err
 		}
-		res, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(msg.Gas()))
+		res, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(msg.GasLimit))
 		if err != nil {
 			return nil, 0, nil, fmt.Errorf("failed to apply transaction: %v err: %v", args.toTransaction().Hash(), err)
 		}

internal/ethapi/backend.go

@@ -68,7 +68,7 @@ type Backend interface {
 	PendingBlockAndReceipts() (*types.Block, types.Receipts)
 	GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error)
 	GetTd(ctx context.Context, hash common.Hash) *big.Int
-	GetEVM(ctx context.Context, msg core.Message, state *state.StateDB, header *types.Header, vmConfig *vm.Config) (*vm.EVM, func() error, error)
+	GetEVM(ctx context.Context, msg *core.Message, state *state.StateDB, header *types.Header, vmConfig *vm.Config) (*vm.EVM, func() error, error)
 	SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription
 	SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription
 	SubscribeChainSideEvent(ch chan<- core.ChainSideEvent) event.Subscription

internal/ethapi/transaction_args.go

@@ -26,6 +26,7 @@ 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/core"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/rpc"
@@ -199,10 +200,10 @@ func (args *TransactionArgs) setLondonFeeDefaults(ctx context.Context, head *typ
 // ToMessage converts the transaction arguments to the Message type used by the
 // core evm. This method is used in calls and traces that do not require a real
 // live transaction.
-func (args *TransactionArgs) ToMessage(globalGasCap uint64, baseFee *big.Int) (types.Message, error) {
+func (args *TransactionArgs) ToMessage(globalGasCap uint64, baseFee *big.Int) (*core.Message, error) {
 	// Reject invalid combinations of pre- and post-1559 fee styles
 	if args.GasPrice != nil && (args.MaxFeePerGas != nil || args.MaxPriorityFeePerGas != nil) {
-		return types.Message{}, errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified")
+		return nil, errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified")
 	}
 	// Set sender address or use zero address if none specified.
 	addr := args.from()
@@ -263,7 +264,18 @@ func (args *TransactionArgs) ToMessage(globalGasCap uint64, baseFee *big.Int) (t
 	if args.AccessList != nil {
 		accessList = *args.AccessList
 	}
-	msg := types.NewMessage(addr, args.To, 0, value, gas, gasPrice, gasFeeCap, gasTipCap, data, accessList, true)
+	msg := &core.Message{
+		From:              addr,
+		To:                args.To,
+		Value:             value,
+		GasLimit:          gas,
+		GasPrice:          gasPrice,
+		GasFeeCap:         gasFeeCap,
+		GasTipCap:         gasTipCap,
+		Data:              data,
+		AccessList:        accessList,
+		SkipAccountChecks: true,
+	}
 	return msg, nil
 }
 

internal/ethapi/transaction_args_test.go

@@ -305,7 +305,7 @@ func (b *backendMock) GetLogs(ctx context.Context, blockHash common.Hash, number
 	return nil, nil
 }
 func (b *backendMock) GetTd(ctx context.Context, hash common.Hash) *big.Int { return nil }
-func (b *backendMock) GetEVM(ctx context.Context, msg core.Message, state *state.StateDB, header *types.Header, vmConfig *vm.Config) (*vm.EVM, func() error, error) {
+func (b *backendMock) GetEVM(ctx context.Context, msg *core.Message, state *state.StateDB, header *types.Header, vmConfig *vm.Config) (*vm.EVM, func() error, error) {
 	return nil, nil, nil
 }
 func (b *backendMock) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription { return nil }