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

light/lightchain.go

@@ -70,9 +70,8 @@ type LightChain struct {
 	wg      sync.WaitGroup
 
 	// Atomic boolean switches:
-	stopped          atomic.Bool // whether LightChain is stopped or running
-	procInterrupt    atomic.Bool // interrupts chain insert
-	disableCheckFreq atomic.Bool // disables header verification
+	stopped       atomic.Bool // whether LightChain is stopped or running
+	procInterrupt atomic.Bool // interrupts chain insert
 }
 
 // NewLightChain returns a fully initialised light chain using information
@@ -345,7 +344,7 @@ func (lc *LightChain) Rollback(chain []common.Hash) {
 func (lc *LightChain) InsertHeader(header *types.Header) error {
 	// Verify the header first before obtaining the lock
 	headers := []*types.Header{header}
-	if _, err := lc.hc.ValidateHeaderChain(headers, 100); err != nil {
+	if _, err := lc.hc.ValidateHeaderChain(headers); err != nil {
 		return err
 	}
 	// Make sure only one thread manipulates the chain at once
@@ -381,23 +380,15 @@ func (lc *LightChain) SetCanonical(header *types.Header) error {
 // InsertHeaderChain attempts to insert the given header chain in to the local
 // chain, possibly creating a reorg. If an error is returned, it will return the
 // index number of the failing header as well an error describing what went wrong.
-//
-// The verify parameter can be used to fine tune whether nonce verification
-// should be done or not. The reason behind the optional check is because some
-// of the header retrieval mechanisms already need to verify nonces, as well as
-// because nonces can be verified sparsely, not needing to check each.
-//
+
 // In the case of a light chain, InsertHeaderChain also creates and posts light
 // chain events when necessary.
-func (lc *LightChain) InsertHeaderChain(chain []*types.Header, checkFreq int) (int, error) {
+func (lc *LightChain) InsertHeaderChain(chain []*types.Header) (int, error) {
 	if len(chain) == 0 {
 		return 0, nil
 	}
-	if lc.disableCheckFreq.Load() {
-		checkFreq = 0
-	}
 	start := time.Now()
-	if i, err := lc.hc.ValidateHeaderChain(chain, checkFreq); err != nil {
+	if i, err := lc.hc.ValidateHeaderChain(chain); err != nil {
 		return i, err
 	}
 
@@ -538,13 +529,3 @@ func (lc *LightChain) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscript
 func (lc *LightChain) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription {
 	return lc.scope.Track(new(event.Feed).Subscribe(ch))
 }
-
-// DisableCheckFreq disables header validation. This is used for ultralight mode.
-func (lc *LightChain) DisableCheckFreq() {
-	lc.disableCheckFreq.Store(true)
-}
-
-// EnableCheckFreq enables header validation.
-func (lc *LightChain) EnableCheckFreq() {
-	lc.disableCheckFreq.Store(false)
-}

light/lightchain_test.go

@@ -64,7 +64,7 @@ func newCanonical(n int) (ethdb.Database, *LightChain, error) {
 	}
 	// Header-only chain requested
 	headers := makeHeaderChain(genesis.Header(), n, db, canonicalSeed)
-	_, err := blockchain.InsertHeaderChain(headers, 1)
+	_, err := blockchain.InsertHeaderChain(headers)
 	return db, blockchain, err
 }
 
@@ -99,7 +99,7 @@ func testFork(t *testing.T, LightChain *LightChain, i, n int, comparator func(td
 	}
 	// Extend the newly created chain
 	headerChainB := makeHeaderChain(LightChain2.CurrentHeader(), n, db, forkSeed)
-	if _, err := LightChain2.InsertHeaderChain(headerChainB, 1); err != nil {
+	if _, err := LightChain2.InsertHeaderChain(headerChainB); err != nil {
 		t.Fatalf("failed to insert forking chain: %v", err)
 	}
 	// Sanity check that the forked chain can be imported into the original
@@ -120,7 +120,7 @@ func testFork(t *testing.T, LightChain *LightChain, i, n int, comparator func(td
 func testHeaderChainImport(chain []*types.Header, lightchain *LightChain) error {
 	for _, header := range chain {
 		// Try and validate the header
-		if err := lightchain.engine.VerifyHeader(lightchain.hc, header, true); err != nil {
+		if err := lightchain.engine.VerifyHeader(lightchain.hc, header); err != nil {
 			return err
 		}
 		// Manually insert the header into the database, but don't reorganize (allows subsequent testing)
@@ -300,8 +300,8 @@ func testReorg(t *testing.T, first, second []int, td int64) {
 	bc := newTestLightChain()
 
 	// Insert an easy and a difficult chain afterwards
-	bc.InsertHeaderChain(makeHeaderChainWithDiff(bc.genesisBlock, first, 11), 1)
-	bc.InsertHeaderChain(makeHeaderChainWithDiff(bc.genesisBlock, second, 22), 1)
+	bc.InsertHeaderChain(makeHeaderChainWithDiff(bc.genesisBlock, first, 11))
+	bc.InsertHeaderChain(makeHeaderChainWithDiff(bc.genesisBlock, second, 22))
 	// Check that the chain is valid number and link wise
 	prev := bc.CurrentHeader()
 	for header := bc.GetHeaderByNumber(bc.CurrentHeader().Number.Uint64() - 1); header.Number.Uint64() != 0; prev, header = header, bc.GetHeaderByNumber(header.Number.Uint64()-1) {
@@ -324,7 +324,7 @@ func TestBadHeaderHashes(t *testing.T) {
 	var err error
 	headers := makeHeaderChainWithDiff(bc.genesisBlock, []int{1, 2, 4}, 10)
 	core.BadHashes[headers[2].Hash()] = true
-	if _, err = bc.InsertHeaderChain(headers, 1); !errors.Is(err, core.ErrBannedHash) {
+	if _, err = bc.InsertHeaderChain(headers); !errors.Is(err, core.ErrBannedHash) {
 		t.Errorf("error mismatch: have: %v, want %v", err, core.ErrBannedHash)
 	}
 }
@@ -337,7 +337,7 @@ func TestReorgBadHeaderHashes(t *testing.T) {
 	// Create a chain, import and ban afterwards
 	headers := makeHeaderChainWithDiff(bc.genesisBlock, []int{1, 2, 3, 4}, 10)
 
-	if _, err := bc.InsertHeaderChain(headers, 1); err != nil {
+	if _, err := bc.InsertHeaderChain(headers); err != nil {
 		t.Fatalf("failed to import headers: %v", err)
 	}
 	if bc.CurrentHeader().Hash() != headers[3].Hash() {

light/odr_test.go

@@ -292,7 +292,7 @@ func testChainOdr(t *testing.T, protocol int, fn odrTestFn) {
 	for i, block := range gchain {
 		headers[i] = block.Header()
 	}
-	if _, err := lightchain.InsertHeaderChain(headers, 1); err != nil {
+	if _, err := lightchain.InsertHeaderChain(headers); err != nil {
 		t.Fatal(err)
 	}
 

light/txpool_test.go

@@ -122,7 +122,7 @@ func TestTxPool(t *testing.T) {
 			}
 		}
 
-		if _, err := lightchain.InsertHeaderChain([]*types.Header{block.Header()}, 1); err != nil {
+		if _, err := lightchain.InsertHeaderChain([]*types.Header{block.Header()}); err != nil {
 			panic(err)
 		}