core: remove notion of future blocks

core/blockchain.go

@@ -50,7 +50,6 @@ import (
 	"github.com/ethereum/go-ethereum/triedb"
 	"github.com/ethereum/go-ethereum/triedb/hashdb"
 	"github.com/ethereum/go-ethereum/triedb/pathdb"
-	"golang.org/x/exp/slices"
 )
 
 var (
@@ -97,13 +96,11 @@ var (
 )
 
 const (
-	bodyCacheLimit      = 256
-	blockCacheLimit     = 256
-	receiptsCacheLimit  = 32
-	txLookupCacheLimit  = 1024
-	maxFutureBlocks     = 256
-	maxTimeFutureBlocks = 30
-	TriesInMemory       = 128
+	bodyCacheLimit     = 256
+	blockCacheLimit    = 256
+	receiptsCacheLimit = 32
+	txLookupCacheLimit = 1024
+	TriesInMemory      = 128
 
 	// BlockChainVersion ensures that an incompatible database forces a resync from scratch.
 	//
@@ -245,9 +242,6 @@ type BlockChain struct {
 	blockCache    *lru.Cache[common.Hash, *types.Block]
 	txLookupCache *lru.Cache[common.Hash, txLookup]
 
-	// future blocks are blocks added for later processing
-	futureBlocks *lru.Cache[common.Hash, *types.Block]
-
 	wg            sync.WaitGroup
 	quit          chan struct{} // shutdown signal, closed in Stop.
 	stopping      atomic.Bool   // false if chain is running, true when stopped
@@ -299,7 +293,6 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, genesis *Genesis
 		receiptsCache: lru.NewCache[common.Hash, []*types.Receipt](receiptsCacheLimit),
 		blockCache:    lru.NewCache[common.Hash, *types.Block](blockCacheLimit),
 		txLookupCache: lru.NewCache[common.Hash, txLookup](txLookupCacheLimit),
-		futureBlocks:  lru.NewCache[common.Hash, *types.Block](maxFutureBlocks),
 		engine:        engine,
 		vmConfig:      vmConfig,
 	}
@@ -449,11 +442,6 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, genesis *Genesis
 		}
 		bc.snaps, _ = snapshot.New(snapconfig, bc.db, bc.triedb, head.Root)
 	}
-
-	// Start future block processor.
-	bc.wg.Add(1)
-	go bc.updateFutureBlocks()
-
 	// Rewind the chain in case of an incompatible config upgrade.
 	if compat, ok := genesisErr.(*params.ConfigCompatError); ok {
 		log.Warn("Rewinding chain to upgrade configuration", "err", compat)
@@ -794,7 +782,6 @@ func (bc *BlockChain) setHeadBeyondRoot(head uint64, time uint64, root common.Ha
 	bc.receiptsCache.Purge()
 	bc.blockCache.Purge()
 	bc.txLookupCache.Purge()
-	bc.futureBlocks.Purge()
 
 	// Clear safe block, finalized block if needed
 	if safe := bc.CurrentSafeBlock(); safe != nil && head < safe.Number.Uint64() {
@@ -1048,24 +1035,6 @@ func (bc *BlockChain) insertStopped() bool {
 	return bc.procInterrupt.Load()
 }
 
-func (bc *BlockChain) procFutureBlocks() {
-	blocks := make([]*types.Block, 0, bc.futureBlocks.Len())
-	for _, hash := range bc.futureBlocks.Keys() {
-		if block, exist := bc.futureBlocks.Peek(hash); exist {
-			blocks = append(blocks, block)
-		}
-	}
-	if len(blocks) > 0 {
-		slices.SortFunc(blocks, func(a, b *types.Block) int {
-			return a.Number().Cmp(b.Number())
-		})
-		// Insert one by one as chain insertion needs contiguous ancestry between blocks
-		for i := range blocks {
-			bc.InsertChain(blocks[i : i+1])
-		}
-	}
-}
-
 // WriteStatus status of write
 type WriteStatus byte
 
@@ -1466,8 +1435,6 @@ func (bc *BlockChain) writeBlockAndSetHead(block *types.Block, receipts []*types
 	if status == CanonStatTy {
 		bc.writeHeadBlock(block)
 	}
-	bc.futureBlocks.Remove(block.Hash())
-
 	if status == CanonStatTy {
 		bc.chainFeed.Send(ChainEvent{Block: block, Hash: block.Hash(), Logs: logs})
 		if len(logs) > 0 {
@@ -1487,25 +1454,6 @@ func (bc *BlockChain) writeBlockAndSetHead(block *types.Block, receipts []*types
 	return status, nil
 }
 
-// addFutureBlock checks if the block is within the max allowed window to get
-// accepted for future processing, and returns an error if the block is too far
-// ahead and was not added.
-//
-// TODO after the transition, the future block shouldn't be kept. Because
-// it's not checked in the Geth side anymore.
-func (bc *BlockChain) addFutureBlock(block *types.Block) error {
-	max := uint64(time.Now().Unix() + maxTimeFutureBlocks)
-	if block.Time() > max {
-		return fmt.Errorf("future block timestamp %v > allowed %v", block.Time(), max)
-	}
-	if block.Difficulty().Cmp(common.Big0) == 0 {
-		// Never add PoS blocks into the future queue
-		return nil
-	}
-	bc.futureBlocks.Add(block.Hash(), block)
-	return nil
-}
-
 // InsertChain attempts to insert the given batch of blocks in to the canonical
 // chain or, otherwise, create a fork. If an error is returned it will return
 // the index number of the failing block as well an error describing what went
@@ -1643,26 +1591,10 @@ func (bc *BlockChain) insertChain(chain types.Blocks, setHead bool) (int, error)
 			_, err := bc.recoverAncestors(block)
 			return it.index, err
 		}
-	// First block is future, shove it (and all children) to the future queue (unknown ancestor)
-	case errors.Is(err, consensus.ErrFutureBlock) || (errors.Is(err, consensus.ErrUnknownAncestor) && bc.futureBlocks.Contains(it.first().ParentHash())):
-		for block != nil && (it.index == 0 || errors.Is(err, consensus.ErrUnknownAncestor)) {
-			log.Debug("Future block, postponing import", "number", block.Number(), "hash", block.Hash())
-			if err := bc.addFutureBlock(block); err != nil {
-				return it.index, err
-			}
-			block, err = it.next()
-		}
-		stats.queued += it.processed()
-		stats.ignored += it.remaining()
-
-		// If there are any still remaining, mark as ignored
-		return it.index, err
-
 	// Some other error(except ErrKnownBlock) occurred, abort.
 	// ErrKnownBlock is allowed here since some known blocks
 	// still need re-execution to generate snapshots that are missing
 	case err != nil && !errors.Is(err, ErrKnownBlock):
-		bc.futureBlocks.Remove(block.Hash())
 		stats.ignored += len(it.chain)
 		bc.reportBlock(block, nil, err)
 		return it.index, err
@@ -1867,23 +1799,7 @@ func (bc *BlockChain) insertChain(chain types.Blocks, setHead bool) (int, error)
 				"root", block.Root())
 		}
 	}
-
-	// Any blocks remaining here? The only ones we care about are the future ones
-	if block != nil && errors.Is(err, consensus.ErrFutureBlock) {
-		if err := bc.addFutureBlock(block); err != nil {
-			return it.index, err
-		}
-		block, err = it.next()
-
-		for ; block != nil && errors.Is(err, consensus.ErrUnknownAncestor); block, err = it.next() {
-			if err := bc.addFutureBlock(block); err != nil {
-				return it.index, err
-			}
-			stats.queued++
-		}
-	}
 	stats.ignored += it.remaining()
-
 	return it.index, err
 }
 
@@ -2334,20 +2250,6 @@ func (bc *BlockChain) SetCanonical(head *types.Block) (common.Hash, error) {
 	return head.Hash(), nil
 }
 
-func (bc *BlockChain) updateFutureBlocks() {
-	futureTimer := time.NewTicker(5 * time.Second)
-	defer futureTimer.Stop()
-	defer bc.wg.Done()
-	for {
-		select {
-		case <-futureTimer.C:
-			bc.procFutureBlocks()
-		case <-bc.quit:
-			return
-		}
-	}
-}
-
 // skipBlock returns 'true', if the block being imported can be skipped over, meaning
 // that the block does not need to be processed but can be considered already fully 'done'.
 func (bc *BlockChain) skipBlock(err error, it *insertIterator) bool {