all: remove ethash pow, only retain shims needed for consensus and tests (ethereum#27178)

* all: remove ethash pow, only retain shims needed for consensus and tests

* all: thank you linter

* all: disallow launching Geth in legacy PoW mode

* cmd/env/internal/t8ntool: remove dangling ethash flag

Author: karalabe

cmd/devp2p/internal/ethtest/testdata/genesis.json

@@ -6,6 +6,7 @@
         "eip155Block": 0,
         "eip158Block": 0,
         "byzantiumBlock": 0,
+        "terminalTotalDifficultyPassed": true,
         "ethash": {}
     },
     "nonce": "0xdeadbeefdeadbeef",

cmd/evm/internal/t8ntool/block.go

@@ -28,7 +28,6 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/consensus/clique"
-	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
@@ -74,11 +73,9 @@ type bbInput struct {
 	Withdrawals []*types.Withdrawal `json:"withdrawals,omitempty"`
 	Clique      *cliqueInput        `json:"clique,omitempty"`
 
-	Ethash    bool                 `json:"-"`
-	EthashDir string               `json:"-"`
-	PowMode   ethash.Mode          `json:"-"`
-	Txs       []*types.Transaction `json:"-"`
-	Ommers    []*types.Header      `json:"-"`
+	Ethash bool                 `json:"-"`
+	Txs    []*types.Transaction `json:"-"`
+	Ommers []*types.Header      `json:"-"`
 }
 
 type cliqueInput struct {
@@ -162,42 +159,13 @@ func (i *bbInput) ToBlock() *types.Block {
 // SealBlock seals the given block using the configured engine.
 func (i *bbInput) SealBlock(block *types.Block) (*types.Block, error) {
 	switch {
-	case i.Ethash:
-		return i.sealEthash(block)
 	case i.Clique != nil:
 		return i.sealClique(block)
 	default:
 		return block, nil
 	}
 }
 
-// sealEthash seals the given block using ethash.
-func (i *bbInput) sealEthash(block *types.Block) (*types.Block, error) {
-	if i.Header.Nonce != nil {
-		return nil, NewError(ErrorConfig, fmt.Errorf("sealing with ethash will overwrite provided nonce"))
-	}
-	ethashConfig := ethash.Config{
-		PowMode:        i.PowMode,
-		DatasetDir:     i.EthashDir,
-		CacheDir:       i.EthashDir,
-		DatasetsInMem:  1,
-		DatasetsOnDisk: 2,
-		CachesInMem:    2,
-		CachesOnDisk:   3,
-	}
-	engine := ethash.New(ethashConfig, nil, true)
-	defer engine.Close()
-	// Use a buffered chan for results.
-	// If the testmode is used, the sealer will return quickly, and complain
-	// "Sealing result is not read by miner" if it cannot write the result.
-	results := make(chan *types.Block, 1)
-	if err := engine.Seal(nil, block, results, nil); err != nil {
-		panic(fmt.Sprintf("failed to seal block: %v", err))
-	}
-	found := <-results
-	return block.WithSeal(found.Header()), nil
-}
-
 // sealClique seals the given block using clique.
 func (i *bbInput) sealClique(block *types.Block) (*types.Block, error) {
 	// If any clique value overwrites an explicit header value, fail
@@ -267,28 +235,8 @@ func readInput(ctx *cli.Context) (*bbInput, error) {
 		withdrawalsStr = ctx.String(InputWithdrawalsFlag.Name)
 		txsStr         = ctx.String(InputTxsRlpFlag.Name)
 		cliqueStr      = ctx.String(SealCliqueFlag.Name)
-		ethashOn       = ctx.Bool(SealEthashFlag.Name)
-		ethashDir      = ctx.String(SealEthashDirFlag.Name)
-		ethashMode     = ctx.String(SealEthashModeFlag.Name)
 		inputData      = &bbInput{}
 	)
-	if ethashOn && cliqueStr != "" {
-		return nil, NewError(ErrorConfig, fmt.Errorf("both ethash and clique sealing specified, only one may be chosen"))
-	}
-	if ethashOn {
-		inputData.Ethash = ethashOn
-		inputData.EthashDir = ethashDir
-		switch ethashMode {
-		case "normal":
-			inputData.PowMode = ethash.ModeNormal
-		case "test":
-			inputData.PowMode = ethash.ModeTest
-		case "fake":
-			inputData.PowMode = ethash.ModeFake
-		default:
-			return nil, NewError(ErrorConfig, fmt.Errorf("unknown pow mode: %s, supported modes: test, fake, normal", ethashMode))
-		}
-	}
 	if headerStr == stdinSelector || ommersStr == stdinSelector || txsStr == stdinSelector || cliqueStr == stdinSelector {
 		decoder := json.NewDecoder(os.Stdin)
 		if err := decoder.Decode(inputData); err != nil {

cmd/evm/internal/t8ntool/flags.go

@@ -125,19 +125,6 @@ var (
 		Name:  "seal.clique",
 		Usage: "Seal block with Clique. `stdin` or file name of where to find the Clique sealing data.",
 	}
-	SealEthashFlag = &cli.BoolFlag{
-		Name:  "seal.ethash",
-		Usage: "Seal block with ethash.",
-	}
-	SealEthashDirFlag = &cli.StringFlag{
-		Name:  "seal.ethash.dir",
-		Usage: "Path to ethash DAG. If none exists, a new DAG will be generated.",
-	}
-	SealEthashModeFlag = &cli.StringFlag{
-		Name:  "seal.ethash.mode",
-		Usage: "Defines the type and amount of PoW verification an ethash engine makes.",
-		Value: "normal",
-	}
 	RewardFlag = &cli.Int64Flag{
 		Name:  "state.reward",
 		Usage: "Mining reward. Set to -1 to disable",

cmd/evm/main.go

@@ -179,9 +179,6 @@ var blockBuilderCommand = &cli.Command{
 		t8ntool.InputWithdrawalsFlag,
 		t8ntool.InputTxsRlpFlag,
 		t8ntool.SealCliqueFlag,
-		t8ntool.SealEthashFlag,
-		t8ntool.SealEthashDirFlag,
-		t8ntool.SealEthashModeFlag,
 		t8ntool.VerbosityFlag,
 	},
 }

cmd/geth/genesis_test.go

@@ -41,7 +41,9 @@ var customGenesisTests = []struct {
 			"mixhash"    : "0x0000000000000000000000000000000000000000000000000000000000000000",
 			"parentHash" : "0x0000000000000000000000000000000000000000000000000000000000000000",
 			"timestamp"  : "0x00",
-			"config"     : {}
+			"config"     : {
+				"terminalTotalDifficultyPassed": true
+			}
 		}`,
 		query:  "eth.getBlock(0).nonce",
 		result: "0x0000000000001338",
@@ -59,9 +61,10 @@ var customGenesisTests = []struct {
 			"parentHash" : "0x0000000000000000000000000000000000000000000000000000000000000000",
 			"timestamp"  : "0x00",
 			"config"     : {
-				"homesteadBlock" : 42,
-				"daoForkBlock"   : 141,
-				"daoForkSupport" : true
+				"homesteadBlock"                : 42,
+				"daoForkBlock"                  : 141,
+				"daoForkSupport"                : true,
+				"terminalTotalDifficultyPassed" : true
 			}
 		}`,
 		query:  "eth.getBlock(0).nonce",
@@ -111,8 +114,10 @@ func TestCustomBackend(t *testing.T) {
 			"mixhash"    : "0x0000000000000000000000000000000000000000000000000000000000000000",
 			"parentHash" : "0x0000000000000000000000000000000000000000000000000000000000000000",
 			"timestamp"  : "0x00",
-			"config"     : {}
-	}`
+			"config"     : {
+				"terminalTotalDifficultyPassed": true
+			}
+		}`
 	type backendTest struct {
 		initArgs   []string
 		initExpect string

cmd/geth/main.go

@@ -66,14 +66,6 @@ var (
 		utils.SmartCardDaemonPathFlag,
 		utils.OverrideCancun,
 		utils.EnablePersonal,
-		utils.EthashCacheDirFlag,
-		utils.EthashCachesInMemoryFlag,
-		utils.EthashCachesOnDiskFlag,
-		utils.EthashCachesLockMmapFlag,
-		utils.EthashDatasetDirFlag,
-		utils.EthashDatasetsInMemoryFlag,
-		utils.EthashDatasetsOnDiskFlag,
-		utils.EthashDatasetsLockMmapFlag,
 		utils.TxPoolLocalsFlag,
 		utils.TxPoolNoLocalsFlag,
 		utils.TxPoolJournalFlag,
@@ -120,14 +112,11 @@ var (
 		utils.MaxPeersFlag,
 		utils.MaxPendingPeersFlag,
 		utils.MiningEnabledFlag,
-		utils.MinerThreadsFlag,
-		utils.MinerNotifyFlag,
 		utils.MinerGasLimitFlag,
 		utils.MinerGasPriceFlag,
 		utils.MinerEtherbaseFlag,
 		utils.MinerExtraDataFlag,
 		utils.MinerRecommitIntervalFlag,
-		utils.MinerNoVerifyFlag,
 		utils.MinerNewPayloadTimeout,
 		utils.NATFlag,
 		utils.NoDiscoverFlag,
@@ -142,13 +131,11 @@ var (
 		utils.VMEnableDebugFlag,
 		utils.NetworkIdFlag,
 		utils.EthStatsURLFlag,
-		utils.FakePoWFlag,
 		utils.NoCompactionFlag,
 		utils.GpoBlocksFlag,
 		utils.GpoPercentileFlag,
 		utils.GpoMaxGasPriceFlag,
 		utils.GpoIgnoreGasPriceFlag,
-		utils.MinerNotifyFullFlag,
 		configFileFlag,
 	}, utils.NetworkFlags, utils.DatabasePathFlags)
 
@@ -224,8 +211,6 @@ func init() {
 		attachCommand,
 		javascriptCommand,
 		// See misccmd.go:
-		makecacheCommand,
-		makedagCommand,
 		versionCommand,
 		versionCheckCommand,
 		licenseCommand,
@@ -438,9 +423,7 @@ func startNode(ctx *cli.Context, stack *node.Node, backend ethapi.Backend, isCon
 		// Set the gas price to the limits from the CLI and start mining
 		gasprice := flags.GlobalBig(ctx, utils.MinerGasPriceFlag.Name)
 		ethBackend.TxPool().SetGasPrice(gasprice)
-		// start mining
-		threads := ctx.Int(utils.MinerThreadsFlag.Name)
-		if err := ethBackend.StartMining(threads); err != nil {
+		if err := ethBackend.StartMining(); err != nil {
 			utils.Fatalf("Failed to start mining: %v", err)
 		}
 	}

cmd/geth/misccmd.go

@@ -20,11 +20,8 @@ import (
 	"fmt"
 	"os"
 	"runtime"
-	"strconv"
 	"strings"
 
-	"github.com/ethereum/go-ethereum/cmd/utils"
-	"github.com/ethereum/go-ethereum/consensus/ethash"
 	"github.com/ethereum/go-ethereum/internal/version"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/urfave/cli/v2"
@@ -41,30 +38,6 @@ var (
 		Usage: "Version to check",
 		Value: version.ClientName(clientIdentifier),
 	}
-	makecacheCommand = &cli.Command{
-		Action:    makecache,
-		Name:      "makecache",
-		Usage:     "Generate ethash verification cache (for testing)",
-		ArgsUsage: "<blockNum> <outputDir>",
-		Description: `
-The makecache command generates an ethash cache in <outputDir>.
-
-This command exists to support the system testing project.
-Regular users do not need to execute it.
-`,
-	}
-	makedagCommand = &cli.Command{
-		Action:    makedag,
-		Name:      "makedag",
-		Usage:     "Generate ethash mining DAG (for testing)",
-		ArgsUsage: "<blockNum> <outputDir>",
-		Description: `
-The makedag command generates an ethash DAG in <outputDir>.
-
-This command exists to support the system testing project.
-Regular users do not need to execute it.
-`,
-	}
 	versionCommand = &cli.Command{
 		Action:    printVersion,
 		Name:      "version",
@@ -96,36 +69,6 @@ and displays information about any security vulnerabilities that affect the curr
 	}
 )
 
-// makecache generates an ethash verification cache into the provided folder.
-func makecache(ctx *cli.Context) error {
-	args := ctx.Args().Slice()
-	if len(args) != 2 {
-		utils.Fatalf(`Usage: geth makecache <block number> <outputdir>`)
-	}
-	block, err := strconv.ParseUint(args[0], 0, 64)
-	if err != nil {
-		utils.Fatalf("Invalid block number: %v", err)
-	}
-	ethash.MakeCache(block, args[1])
-
-	return nil
-}
-
-// makedag generates an ethash mining DAG into the provided folder.
-func makedag(ctx *cli.Context) error {
-	args := ctx.Args().Slice()
-	if len(args) != 2 {
-		utils.Fatalf(`Usage: geth makedag <block number> <outputdir>`)
-	}
-	block, err := strconv.ParseUint(args[0], 0, 64)
-	if err != nil {
-		utils.Fatalf("Invalid block number: %v", err)
-	}
-	ethash.MakeDataset(block, args[1])
-
-	return nil
-}
-
 func printVersion(ctx *cli.Context) error {
 	git, _ := version.VCS()