eth, eth/downloader: remove references to LightChain, LightSync

eth/backend.go

@@ -19,7 +19,6 @@ package eth
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"math/big"
 	"runtime"
@@ -105,9 +104,6 @@ type Ethereum struct {
 // whose lifecycle will be managed by the provided node.
 func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 	// Ensure configuration values are compatible and sane
-	if config.SyncMode == downloader.LightSync {
-		return nil, errors.New("can't run eth.Ethereum in light sync mode, light mode has been deprecated")
-	}
 	if !config.SyncMode.IsValid() {
 		return nil, fmt.Errorf("invalid sync mode %d", config.SyncMode)
 	}

eth/downloader/beaconsync.go

@@ -202,7 +202,7 @@ func (d *Downloader) findBeaconAncestor() (uint64, error) {
 	case SnapSync:
 		chainHead = d.blockchain.CurrentSnapBlock()
 	default:
-		chainHead = d.lightchain.CurrentHeader()
+		panic("unknown sync mode")
 	}
 	number := chainHead.Number.Uint64()
 
@@ -222,7 +222,7 @@ func (d *Downloader) findBeaconAncestor() (uint64, error) {
 	case SnapSync:
 		linked = d.blockchain.HasFastBlock(beaconTail.ParentHash, beaconTail.Number.Uint64()-1)
 	default:
-		linked = d.blockchain.HasHeader(beaconTail.ParentHash, beaconTail.Number.Uint64()-1)
+		panic("unknown sync mode")
 	}
 	if !linked {
 		// This is a programming error. The chain backfiller was called with a
@@ -257,7 +257,7 @@ func (d *Downloader) findBeaconAncestor() (uint64, error) {
 		case SnapSync:
 			known = d.blockchain.HasFastBlock(h.Hash(), n)
 		default:
-			known = d.lightchain.HasHeader(h.Hash(), n)
+			panic("unknown sync mode")
 		}
 		if !known {
 			end = check

eth/downloader/downloader.go

@@ -67,7 +67,6 @@ var (
 	errCancelContentProcessing = errors.New("content processing canceled (requested)")
 	errCanceled                = errors.New("syncing canceled (requested)")
 	errNoPivotHeader           = errors.New("pivot header is not found")
-	ErrMergeTransition         = errors.New("legacy sync reached the merge")
 )
 
 // peerDropFn is a callback type for dropping a peer detected as malicious.
@@ -98,7 +97,6 @@ type Downloader struct {
 	syncStatsChainHeight uint64       // Highest block number known when syncing started
 	syncStatsLock        sync.RWMutex // Lock protecting the sync stats fields
 
-	lightchain LightChain
 	blockchain BlockChain
 
 	// Callbacks
@@ -143,8 +141,8 @@ type Downloader struct {
 	syncLogTime    time.Time // Time instance when status was last reported
 }
 
-// LightChain encapsulates functions required to synchronise a light chain.
-type LightChain interface {
+// BlockChain encapsulates functions required to sync a (full or snap) blockchain.
+type BlockChain interface {
 	// HasHeader verifies a header's presence in the local chain.
 	HasHeader(common.Hash, uint64) bool
 
@@ -162,11 +160,6 @@ type LightChain interface {
 
 	// SetHead rewinds the local chain to a new head.
 	SetHead(uint64) error
-}
-
-// BlockChain encapsulates functions required to sync a (full or snap) blockchain.
-type BlockChain interface {
-	LightChain
 
 	// HasBlock verifies a block's presence in the local chain.
 	HasBlock(common.Hash, uint64) bool
@@ -201,17 +194,13 @@ type BlockChain interface {
 }
 
 // New creates a new downloader to fetch hashes and blocks from remote peers.
-func New(stateDb ethdb.Database, mux *event.TypeMux, chain BlockChain, lightchain LightChain, dropPeer peerDropFn, success func()) *Downloader {
-	if lightchain == nil {
-		lightchain = chain
-	}
+func New(stateDb ethdb.Database, mux *event.TypeMux, chain BlockChain, dropPeer peerDropFn, success func()) *Downloader {
 	dl := &Downloader{
 		stateDB:        stateDb,
 		mux:            mux,
 		queue:          newQueue(blockCacheMaxItems, blockCacheInitialItems),
 		peers:          newPeerSet(),
 		blockchain:     chain,
-		lightchain:     lightchain,
 		dropPeer:       dropPeer,
 		headerProcCh:   make(chan *headerTask, 1),
 		quitCh:         make(chan struct{}),
@@ -240,15 +229,13 @@ func (d *Downloader) Progress() ethereum.SyncProgress {
 
 	current := uint64(0)
 	mode := d.getMode()
-	switch {
-	case d.blockchain != nil && mode == FullSync:
+	switch mode {
+	case FullSync:
 		current = d.blockchain.CurrentBlock().Number.Uint64()
-	case d.blockchain != nil && mode == SnapSync:
+	case SnapSync:
 		current = d.blockchain.CurrentSnapBlock().Number.Uint64()
-	case d.lightchain != nil:
-		current = d.lightchain.CurrentHeader().Number.Uint64()
 	default:
-		log.Error("Unknown downloader chain/mode combo", "light", d.lightchain != nil, "full", d.blockchain != nil, "mode", mode)
+		log.Error("Unknown downloader mode", "mode", mode)
 	}
 	progress, pending := d.SnapSyncer.Progress()
 
@@ -402,7 +389,7 @@ func (d *Downloader) syncToHead() (err error) {
 		if err != nil {
 			d.mux.Post(FailedEvent{err})
 		} else {
-			latest := d.lightchain.CurrentHeader()
+			latest := d.blockchain.CurrentHeader()
 			d.mux.Post(DoneEvent{latest})
 		}
 	}()
@@ -520,7 +507,7 @@ func (d *Downloader) syncToHead() (err error) {
 		}
 		// Rewind the ancient store and blockchain if reorg happens.
 		if origin+1 < frozen {
-			if err := d.lightchain.SetHead(origin); err != nil {
+			if err := d.blockchain.SetHead(origin); err != nil {
 				return err
 			}
 			log.Info("Truncated excess ancient chain segment", "oldhead", frozen-1, "newhead", origin)
@@ -690,34 +677,32 @@ func (d *Downloader) processHeaders(origin uint64) error {
 				chunkHashes := hashes[:limit]
 
 				// In case of header only syncing, validate the chunk immediately
-				if mode == SnapSync || mode == LightSync {
+				if mode == SnapSync {
 					// Although the received headers might be all valid, a legacy
 					// PoW/PoA sync must not accept post-merge headers. Make sure
 					// that any transition is rejected at this point.
 					if len(chunkHeaders) > 0 {
-						if n, err := d.lightchain.InsertHeaderChain(chunkHeaders); err != nil {
+						if n, err := d.blockchain.InsertHeaderChain(chunkHeaders); err != nil {
 							log.Warn("Invalid header encountered", "number", chunkHeaders[n].Number, "hash", chunkHashes[n], "parent", chunkHeaders[n].ParentHash, "err", err)
 							return fmt.Errorf("%w: %v", errInvalidChain, err)
 						}
 					}
 				}
-				// Unless we're doing light chains, schedule the headers for associated content retrieval
-				if mode == FullSync || mode == SnapSync {
-					// If we've reached the allowed number of pending headers, stall a bit
-					for d.queue.PendingBodies() >= maxQueuedHeaders || d.queue.PendingReceipts() >= maxQueuedHeaders {
-						timer.Reset(time.Second)
-						select {
-						case <-d.cancelCh:
-							return errCanceled
-						case <-timer.C:
-						}
-					}
-					// Otherwise insert the headers for content retrieval
-					inserts := d.queue.Schedule(chunkHeaders, chunkHashes, origin)
-					if len(inserts) != len(chunkHeaders) {
-						return fmt.Errorf("%w: stale headers", errBadPeer)
+				// If we've reached the allowed number of pending headers, stall a bit
+				for d.queue.PendingBodies() >= maxQueuedHeaders || d.queue.PendingReceipts() >= maxQueuedHeaders {
+					timer.Reset(time.Second)
+					select {
+					case <-d.cancelCh:
+						return errCanceled
+					case <-timer.C:
 					}
 				}
+				// Otherwise insert the headers for content retrieval
+				inserts := d.queue.Schedule(chunkHeaders, chunkHashes, origin)
+				if len(inserts) != len(chunkHeaders) {
+					return fmt.Errorf("%w: stale headers", errBadPeer)
+				}
+
 				headers = headers[limit:]
 				hashes = hashes[limit:]
 				origin += uint64(limit)
@@ -1056,7 +1041,7 @@ func (d *Downloader) readHeaderRange(last *types.Header, count int) []*types.Hea
 		headers []*types.Header
 	)
 	for {
-		parent := d.lightchain.GetHeaderByHash(current.ParentHash)
+		parent := d.blockchain.GetHeaderByHash(current.ParentHash)
 		if parent == nil {
 			break // The chain is not continuous, or the chain is exhausted
 		}

eth/downloader/downloader_test.go

@@ -80,7 +80,7 @@ func newTesterWithNotification(t *testing.T, success func()) *downloadTester {
 		chain:   chain,
 		peers:   make(map[string]*downloadTesterPeer),
 	}
-	tester.downloader = New(db, new(event.TypeMux), tester.chain, nil, tester.dropPeer, success)
+	tester.downloader = New(db, new(event.TypeMux), tester.chain, tester.dropPeer, success)
 	return tester
 }
 
@@ -390,9 +390,6 @@ func assertOwnChain(t *testing.T, tester *downloadTester, length int) {
 	t.Helper()
 
 	headers, blocks, receipts := length, length, length
-	if tester.downloader.getMode() == LightSync {
-		blocks, receipts = 1, 1
-	}
 	if hs := int(tester.chain.CurrentHeader().Number.Uint64()) + 1; hs != headers {
 		t.Fatalf("synchronised headers mismatch: have %v, want %v", hs, headers)
 	}
@@ -404,9 +401,8 @@ func assertOwnChain(t *testing.T, tester *downloadTester, length int) {
 	}
 }
 
-func TestCanonicalSynchronisation68Full(t *testing.T)  { testCanonSync(t, eth.ETH68, FullSync) }
-func TestCanonicalSynchronisation68Snap(t *testing.T)  { testCanonSync(t, eth.ETH68, SnapSync) }
-func TestCanonicalSynchronisation68Light(t *testing.T) { testCanonSync(t, eth.ETH68, LightSync) }
+func TestCanonicalSynchronisation68Full(t *testing.T) { testCanonSync(t, eth.ETH68, FullSync) }
+func TestCanonicalSynchronisation68Snap(t *testing.T) { testCanonSync(t, eth.ETH68, SnapSync) }
 
 func testCanonSync(t *testing.T, protocol uint, mode SyncMode) {
 	success := make(chan struct{})
@@ -511,9 +507,8 @@ func testThrottling(t *testing.T, protocol uint, mode SyncMode) {
 }
 
 // Tests that a canceled download wipes all previously accumulated state.
-func TestCancel68Full(t *testing.T)  { testCancel(t, eth.ETH68, FullSync) }
-func TestCancel68Snap(t *testing.T)  { testCancel(t, eth.ETH68, SnapSync) }
-func TestCancel68Light(t *testing.T) { testCancel(t, eth.ETH68, LightSync) }
+func TestCancel68Full(t *testing.T) { testCancel(t, eth.ETH68, FullSync) }
+func TestCancel68Snap(t *testing.T) { testCancel(t, eth.ETH68, SnapSync) }
 
 func testCancel(t *testing.T, protocol uint, mode SyncMode) {
 	complete := make(chan struct{})
@@ -544,9 +539,8 @@ func testCancel(t *testing.T, protocol uint, mode SyncMode) {
 
 // Tests that synchronisations behave well in multi-version protocol environments
 // and not wreak havoc on other nodes in the network.
-func TestMultiProtoSynchronisation68Full(t *testing.T)  { testMultiProtoSync(t, eth.ETH68, FullSync) }
-func TestMultiProtoSynchronisation68Snap(t *testing.T)  { testMultiProtoSync(t, eth.ETH68, SnapSync) }
-func TestMultiProtoSynchronisation68Light(t *testing.T) { testMultiProtoSync(t, eth.ETH68, LightSync) }
+func TestMultiProtoSynchronisation68Full(t *testing.T) { testMultiProtoSync(t, eth.ETH68, FullSync) }
+func TestMultiProtoSynchronisation68Snap(t *testing.T) { testMultiProtoSync(t, eth.ETH68, SnapSync) }
 
 func testMultiProtoSync(t *testing.T, protocol uint, mode SyncMode) {
 	complete := make(chan struct{})
@@ -584,9 +578,8 @@ func testMultiProtoSync(t *testing.T, protocol uint, mode SyncMode) {
 
 // Tests that if a block is empty (e.g. header only), no body request should be
 // made, and instead the header should be assembled into a whole block in itself.
-func TestEmptyShortCircuit68Full(t *testing.T)  { testEmptyShortCircuit(t, eth.ETH68, FullSync) }
-func TestEmptyShortCircuit68Snap(t *testing.T)  { testEmptyShortCircuit(t, eth.ETH68, SnapSync) }
-func TestEmptyShortCircuit68Light(t *testing.T) { testEmptyShortCircuit(t, eth.ETH68, LightSync) }
+func TestEmptyShortCircuit68Full(t *testing.T) { testEmptyShortCircuit(t, eth.ETH68, FullSync) }
+func TestEmptyShortCircuit68Snap(t *testing.T) { testEmptyShortCircuit(t, eth.ETH68, SnapSync) }
 
 func testEmptyShortCircuit(t *testing.T, protocol uint, mode SyncMode) {
 	success := make(chan struct{})
@@ -625,7 +618,7 @@ func testEmptyShortCircuit(t *testing.T, protocol uint, mode SyncMode) {
 	// Validate the number of block bodies that should have been requested
 	bodiesNeeded, receiptsNeeded := 0, 0
 	for _, block := range chain.blocks[1:] {
-		if mode != LightSync && (len(block.Transactions()) > 0 || len(block.Uncles()) > 0) {
+		if len(block.Transactions()) > 0 || len(block.Uncles()) > 0 {
 			bodiesNeeded++
 		}
 	}
@@ -700,9 +693,8 @@ func testBeaconSync(t *testing.T, protocol uint, mode SyncMode) {
 
 // Tests that synchronisation progress (origin block number, current block number
 // and highest block number) is tracked and updated correctly.
-func TestSyncProgress68Full(t *testing.T)  { testSyncProgress(t, eth.ETH68, FullSync) }
-func TestSyncProgress68Snap(t *testing.T)  { testSyncProgress(t, eth.ETH68, SnapSync) }
-func TestSyncProgress68Light(t *testing.T) { testSyncProgress(t, eth.ETH68, LightSync) }
+func TestSyncProgress68Full(t *testing.T) { testSyncProgress(t, eth.ETH68, FullSync) }
+func TestSyncProgress68Snap(t *testing.T) { testSyncProgress(t, eth.ETH68, SnapSync) }
 
 func testSyncProgress(t *testing.T, protocol uint, mode SyncMode) {
 	success := make(chan struct{})
@@ -740,17 +732,7 @@ func testSyncProgress(t *testing.T, protocol uint, mode SyncMode) {
 	if err := tester.downloader.BeaconSync(mode, chain.blocks[len(chain.blocks)-1].Header(), nil); err != nil {
 		t.Fatalf("failed to beacon-sync chain: %v", err)
 	}
-	var startingBlock uint64
-	if mode == LightSync {
-		// in light-sync mode:
-		// * the starting block is 0 on the second sync cycle because blocks
-		//   are never downloaded.
-		// * The current/highest blocks reported in the progress reflect the
-		//   current/highest header.
-		startingBlock = 0
-	} else {
-		startingBlock = uint64(len(chain.blocks)/2 - 1)
-	}
+	startingBlock := uint64(len(chain.blocks)/2 - 1)
 
 	select {
 	case <-success:

eth/downloader/modes.go

@@ -23,13 +23,12 @@ import "fmt"
 type SyncMode uint32
 
 const (
-	FullSync  SyncMode = iota // Synchronise the entire blockchain history from full blocks
-	SnapSync                  // Download the chain and the state via compact snapshots
-	LightSync                 // Download only the headers and terminate afterwards
+	FullSync SyncMode = iota // Synchronise the entire blockchain history from full blocks
+	SnapSync                 // Download the chain and the state via compact snapshots
 )
 
 func (mode SyncMode) IsValid() bool {
-	return mode >= FullSync && mode <= LightSync
+	return mode == FullSync || mode == SnapSync
 }
 
 // String implements the stringer interface.
@@ -39,8 +38,6 @@ func (mode SyncMode) String() string {
 		return "full"
 	case SnapSync:
 		return "snap"
-	case LightSync:
-		return "light"
 	default:
 		return "unknown"
 	}
@@ -52,8 +49,6 @@ func (mode SyncMode) MarshalText() ([]byte, error) {
 		return []byte("full"), nil
 	case SnapSync:
 		return []byte("snap"), nil
-	case LightSync:
-		return []byte("light"), nil
 	default:
 		return nil, fmt.Errorf("unknown sync mode %d", mode)
 	}
@@ -65,10 +60,8 @@ func (mode *SyncMode) UnmarshalText(text []byte) error {
 		*mode = FullSync
 	case "snap":
 		*mode = SnapSync
-	case "light":
-		*mode = LightSync
 	default:
-		return fmt.Errorf(`unknown sync mode %q, want "full", "snap" or "light"`, text)
+		return fmt.Errorf(`unknown sync mode %q, want "full" or "snap"`, text)
 	}
 	return nil
 }

eth/handler.go

@@ -180,7 +180,7 @@ func newHandler(config *handlerConfig) (*handler, error) {
 		return nil, errors.New("snap sync not supported with snapshots disabled")
 	}
 	// Construct the downloader (long sync)
-	h.downloader = downloader.New(config.Database, h.eventMux, h.chain, nil, h.removePeer, h.enableSyncedFeatures)
+	h.downloader = downloader.New(config.Database, h.eventMux, h.chain, h.removePeer, h.enableSyncedFeatures)
 
 	fetchTx := func(peer string, hashes []common.Hash) error {
 		p := h.peers.peer(peer)