Legacy ibft should be used if qibftBlock is not defined in genesis

consensus/istanbul/backend/backend.go

@@ -327,13 +327,15 @@ func (sb *backend) Close() error {
 
 // IsQIBFTConsensus returns whether qbft consensus should be used
 func (sb *backend) IsQIBFTConsensus() bool {
-	if sb.qibftConsensusEnabled {
-		return true
-	}
-	// If it is a new network then by default use qibft consensus
-	if sb.config.QibftBlock == nil || sb.config.QibftBlock.Uint64() == 0 {
+	// If qibftBlock is not defined in genesis, then use legacy ibft
+	if sb.config.QibftBlock == nil {
+		return false
+	}
+
+	if sb.qibftConsensusEnabled || sb.config.QibftBlock.Uint64() == 0{
 		return true
 	}
+
 	if sb.chain != nil && sb.chain.CurrentHeader().Number.Cmp(sb.config.QibftBlock) >= 0 {
 		return true
 	}

consensus/istanbul/core/handler.go

@@ -39,8 +39,9 @@ func (c *core) Stop() error {
 	c.stopTimer()
 	c.unsubscribeEvents()
 
-	// Make sure the handler goroutine exits
-	c.handlerWg.Wait()
+	// Not waiting for handlerWg to stop, as it was blocking legacy IBFT consensus to stop
+	// and new events will be handled by qibft consensus
+	// c.handlerWg.Wait()
 	return nil
 }
 

eth/backend.go

@@ -283,11 +283,7 @@ func CreateConsensusEngine(ctx *node.ServiceContext, chainConfig *params.ChainCo
 		config.Istanbul.ProposerPolicy = istanbul.ProposerPolicy(chainConfig.Istanbul.ProposerPolicy)
 		config.Istanbul.Ceil2Nby3Block = chainConfig.Istanbul.Ceil2Nby3Block
 		config.Istanbul.AllowedFutureBlockTime = config.AllowedFutureBlockTime
-
 		config.Istanbul.QibftBlock = chainConfig.Istanbul.QibftBlock
-		if chainConfig.Istanbul.QibftBlock == nil {
-			config.Istanbul.QibftBlock = big.NewInt(0)
-		}
 
 		return istanbulBackend.New(&config.Istanbul, ctx.NodeKey(), db)
 	}