fix: only upgrade last sync block if no later chain head exists

Author: ARR4N

blocks/execution.go

@@ -48,13 +48,16 @@ func (e *executionResults) Equal(f *executionResults) bool {
 }
 
 // MarkExecuted marks the block as having being executed at the specified
-// time(s) and with the specified results. This function MUST NOT be called more
-// than once. The wall-clock [time.Time] is for metrics only.
+// time(s) and with the specified results. It also sets the chain's head block
+// to b.
 //
 // MarkExecuted guarantees that state is persisted to the database before
 // in-memory indicators of execution are updated. [Block.Executed] returning
 // true is therefore indicative of a successful database write by MarkExecuted.
-func (b *Block) MarkExecuted(db ethdb.Database, isLastSyncBlock bool, byGas *gastime.Time, byWall time.Time, receipts types.Receipts, stateRootPost common.Hash) error {
+//
+// This function MUST NOT be called more than once. The wall-clock [time.Time]
+// is for metrics only.
+func (b *Block) MarkExecuted(db ethdb.Database, byGas *gastime.Time, byWall time.Time, receipts types.Receipts, stateRootPost common.Hash) error {
 	var used gas.Gas
 	for _, r := range receipts {
 		used += gas.Gas(r.GasUsed)
@@ -70,14 +73,8 @@ func (b *Block) MarkExecuted(db ethdb.Database, isLastSyncBlock bool, byGas *gas
 	}
 
 	batch := db.NewBatch()
-	if !isLastSyncBlock {
-		// Although the last synchronous block is required to be the head block
-		// at the time of upgrade, not setting the head here allows this method
-		// to be called idempotently for that block. This is useful when
-		// converting it to an SAE block.
-		rawdb.WriteHeadBlockHash(batch, b.Hash())
-		rawdb.WriteHeadHeaderHash(batch, b.Hash())
-	}
+	rawdb.WriteHeadBlockHash(batch, b.Hash())
+	rawdb.WriteHeadHeaderHash(batch, b.Hash())
 	rawdb.WriteReceipts(batch, b.Hash(), b.NumberU64(), receipts)
 	if err := b.writePostExecutionState(batch, e); err != nil {
 		return err

db.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"math/big"
 
 	"github.com/ava-labs/avalanchego/database"
 	"github.com/ava-labs/libevm/common"
@@ -19,6 +20,11 @@ func (vm *VM) upgradeLastSynchronousBlock(hash common.Hash) error {
 	if lastSyncNum == nil {
 		return fmt.Errorf("read number of last synchronous block (%#x): %w", hash, database.ErrNotFound)
 	}
+	lastSyncNumBig := new(big.Int).SetUint64(*lastSyncNum)
+	if rawdb.ReadHeadHeader(vm.db).Number.Cmp(lastSyncNumBig) > 0 {
+		return nil
+	}
+
 	ethBlock := rawdb.ReadBlock(vm.db, hash, *lastSyncNum)
 	if ethBlock == nil {
 		return fmt.Errorf("read last synchronous block (%#x): %w", hash, database.ErrNotFound)
@@ -45,7 +51,7 @@ func (vm *VM) upgradeLastSynchronousBlock(hash common.Hash) error {
 		1e6, 0,
 	)
 	receipts := rawdb.ReadRawReceipts(vm.db, hash, block.Height())
-	if err := block.MarkExecuted(vm.db, true, clock, block.Timestamp(), receipts, block.Root()); err != nil {
+	if err := block.MarkExecuted(vm.db, clock, block.Timestamp(), receipts, block.Root()); err != nil {
 		return err
 	}
 	if err := block.WriteLastSettledNumber(vm.db); err != nil {

saexec/execution.go

@@ -135,7 +135,7 @@ func (e *Executor) execute(ctx context.Context, b *blocks.Block) error {
 	// 1. [blocks.Block.MarkExecuted] guarantees disk then in-memory changes.
 	// 2. Internal indicator of last executed MUST follow in-memory change.
 	// 3. External indicator of last executed MUST follow internal indicator.
-	if err := b.MarkExecuted(e.db, false, e.gasClock.Clone(), endTime, receipts, root); err != nil {
+	if err := b.MarkExecuted(e.db, e.gasClock.Clone(), endTime, receipts, root); err != nil {
 		return err
 	}
 	e.lastExecuted.Store(b)                      // (2)