feat: avoid unnecessary block notifications when the event bus is already set up

CHANGELOG.md

@@ -20,6 +20,7 @@
 - [\#467](https://github.com/cosmos/evm/pull/467) Replace GlobalEVMMempool by passing to JSONRPC on initiate.
 - [\#352](https://github.com/cosmos/evm/pull/352) Remove the creation of a Geth EVM instance, stateDB during the AnteHandler balance check.
 - [\#496](https://github.com/cosmos/evm/pull/496) Simplify mempool instantiation by using configs instead of objects.
+- [\#568](https://github.com/cosmos/evm/pull/568) Avoid unnecessary block notifications when the event bus is already set up.
 - [\#511](https://github.com/cosmos/evm/pull/511) Minor code cleanup for `AddPrecompileFn`.
 
 ### FEATURES

mempool/blockchain.go

@@ -86,6 +86,11 @@ func (b Blockchain) CurrentBlock() *types.Header {
 	}
 
 	blockHeight := ctx.BlockHeight()
+	// prevent the reorg from triggering after a restart since previousHeaderHash is stored as an in-memory variable
+	if blockHeight > 1 && b.previousHeaderHash == (common.Hash{}) {
+		return b.zeroHeader
+	}
+
 	blockTime := ctx.BlockTime().Unix()
 	gasUsed := b.feeMarketKeeper.GetBlockGasWanted(ctx)
 	appHash := common.BytesToHash(ctx.BlockHeader().AppHash)

mempool/mempool.go

@@ -381,7 +381,7 @@ func (m *ExperimentalEVMMempool) SelectBy(goCtx context.Context, i [][]byte, f f
 
 // SetEventBus sets CometBFT event bus to listen for new block header event.
 func (m *ExperimentalEVMMempool) SetEventBus(eventBus *cmttypes.EventBus) {
-	if m.eventBus != nil {
+	if m.HasEventBus() {
 		m.eventBus.Unsubscribe(context.Background(), SubscriberName, stream.NewBlockHeaderEvents) //nolint: errcheck
 	}
 	m.eventBus = eventBus
@@ -396,6 +396,11 @@ func (m *ExperimentalEVMMempool) SetEventBus(eventBus *cmttypes.EventBus) {
 	}()
 }
 
+// HasEventBus returns true if the blockchain is configured to use an event bus for block notifications.
+func (m *ExperimentalEVMMempool) HasEventBus() bool {
+	return m.eventBus != nil
+}
+
 // Close unsubscribes from the CometBFT event bus and shuts down the mempool.
 func (m *ExperimentalEVMMempool) Close() error {
 	var errs []error

x/vm/keeper/abci.go

@@ -43,7 +43,7 @@ func (k *Keeper) EndBlock(ctx sdk.Context) error {
 	// Gas costs are handled within msg handler so costs should be ignored
 	infCtx := ctx.WithGasMeter(storetypes.NewInfiniteGasMeter())
 
-	if k.evmMempool != nil {
+	if k.evmMempool != nil && !k.evmMempool.HasEventBus() {
 		k.evmMempool.GetBlockchain().NotifyNewBlock()
 	}