core/txpool: set 128 blocks as the fallback value for old blob eviction

Author: txhsl

core/txpool/blobpool/blobpool.go

@@ -840,9 +840,7 @@ func (p *BlobPool) Reset(oldHead, newHead *types.Header) {
 	}
 	// Flush out any blobs from limbo that are older than the latest finality
 	if p.chain.Config().IsCancun(p.head.Number, p.head.Time) {
-		if h := p.chain.CurrentFinalBlock(); h != nil {
-			p.limbo.finalize(h)
-		}
+		p.limbo.finalize(p.chain.CurrentFinalBlock(), newHead)
 	}
 	// Reset the price heap for the new set of basefee/blobfee pairs
 	var (

core/txpool/blobpool/limbo.go

@@ -112,15 +112,25 @@ func (l *limbo) parseBlob(id uint64, data []byte) error {
 }
 
 // finalize evicts all blobs belonging to a recently finalized block or older.
-func (l *limbo) finalize(final *types.Header) {
+func (l *limbo) finalize(final *types.Header, current *types.Header) {
 	// Just in case there's no final block yet (network not yet merged, weird
-	// restart, sethead, etc), fail gracefully.
-	if final == nil {
-		log.Error("Nil finalized block cannot evict old blobs")
-		return
+	// restart, sethead, etc), take 128 blocks ago as fallback.
+	// TODO: Remove this fallback once there is a stable source of finality.
+	// 128 is an impossible reorg depth, for about 10 mins under 5s block time.
+	last := uint64(0)
+	if final != nil {
+		last = final.Number.Uint64()
+	} else {
+		if current == nil {
+			log.Error("Nil finalized and current block cannot evict old blobs")
+			return
+		}
+		if current.Number.Uint64() > 128 {
+			last = current.Number.Uint64() - 128
+		}
 	}
 	for block, ids := range l.groups {
-		if block > final.Number.Uint64() {
+		if block > last {
 			continue
 		}
 		for id, owner := range ids {