Mempool WAL is still created by default in home directory, leads to permission errors (#2758)

* only invoke InitWAL/CloseWAL if WalPath is not empty

Closes #2717

* panic if WAL is not initialized when calling CloseWAL

* add a changelog entry

node/node.go

@@ -13,8 +13,8 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"github.com/tendermint/go-amino"
 
+	amino "github.com/tendermint/go-amino"
 	abci "github.com/tendermint/tendermint/abci/types"
 	bc "github.com/tendermint/tendermint/blockchain"
 	cfg "github.com/tendermint/tendermint/config"
@@ -279,7 +279,9 @@ func NewNode(config *cfg.Config,
 	)
 	mempoolLogger := logger.With("module", "mempool")
 	mempool.SetLogger(mempoolLogger)
-	mempool.InitWAL() // no need to have the mempool wal during tests
+	if config.Mempool.WalEnabled() {
+		mempool.InitWAL() // no need to have the mempool wal during tests
+	}
 	mempoolReactor := mempl.NewMempoolReactor(config.Mempool, mempool)
 	mempoolReactor.SetLogger(mempoolLogger)
 
@@ -586,6 +588,11 @@ func (n *Node) OnStop() {
 	// TODO: gracefully disconnect from peers.
 	n.sw.Stop()
 
+	// stop mempool WAL
+	if n.config.Mempool.WalEnabled() {
+		n.mempoolReactor.Mempool.CloseWAL()
+	}
+
 	if err := n.transport.Close(); err != nil {
 		n.Logger.Error("Error closing transport", "err", err)
 	}