core: fix fork readiness log (#32623)

When I implemented in #31340 I didn't expect multiple forks to be
configured at once, but this is exactly how BPOs are defined. This
updates the method to determine the next scheduled fork rather than the
last fork.

core/blockchain.go

@@ -21,7 +21,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"math"
 	"math/big"
 	"runtime"
 	"slices"
@@ -2663,13 +2662,11 @@ func (bc *BlockChain) reportBlock(block *types.Block, res *ProcessResult, err er
 // logForkReadiness will write a log when a future fork is scheduled, but not
 // active. This is useful so operators know their client is ready for the fork.
 func (bc *BlockChain) logForkReadiness(block *types.Block) {
-	config := bc.Config()
-	current, last := config.LatestFork(block.Time()), config.LatestFork(math.MaxUint64)
+	current := bc.Config().LatestFork(block.Time())
 
-	// Short circuit if the timestamp of the last fork is undefined,
-	// or if the network has already passed the last configured fork.
-	t := config.Timestamp(last)
-	if t == nil || current >= last {
+	// Short circuit if the timestamp of the last fork is undefined.
+	t := bc.Config().Timestamp(current + 1)
+	if t == nil {
 		return
 	}
 	at := time.Unix(int64(*t), 0)
@@ -2679,7 +2676,7 @@ func (bc *BlockChain) logForkReadiness(block *types.Block) {
 	// - Enough time has passed since last alert
 	now := time.Now()
 	if now.Before(at) && now.After(bc.lastForkReadyAlert.Add(forkReadyInterval)) {
-		log.Info("Ready for fork activation", "fork", last, "date", at.Format(time.RFC822),
+		log.Info("Ready for fork activation", "fork", current+1, "date", at.Format(time.RFC822),
 			"remaining", time.Until(at).Round(time.Second), "timestamp", at.Unix())
 		bc.lastForkReadyAlert = time.Now()
 	}

params/forks/forks.go

@@ -77,4 +77,9 @@ var forkToString = map[Fork]string{
 	Cancun:           "Cancun",
 	Prague:           "Prague",
 	Osaka:            "Osaka",
+	BPO1:             "BPO1",
+	BPO2:             "BPO2",
+	BPO3:             "BPO3",
+	BPO4:             "BPO4",
+	BPO5:             "BPO5",
 }