Add test which fails without patch, comment on patch

baseapp/baseapp.go

@@ -190,6 +190,7 @@ func (app *BaseApp) initFromStore(mainKey sdk.StoreKey) error {
 	if main == nil {
 		return errors.New("baseapp expects MultiStore with 'main' KVStore")
 	}
+	// Needed for `gaiad export`, which inits from store but never calls initchain
 	app.setCheckState(abci.Header{})
 	return nil
 }

cmd/gaia/app/app_test.go

@@ -1,9 +1,15 @@
 package app
 
 import (
+	"os"
+	"testing"
+
 	"github.com/cosmos/cosmos-sdk/wire"
 	"github.com/cosmos/cosmos-sdk/x/auth"
 	"github.com/cosmos/cosmos-sdk/x/stake"
+	"github.com/stretchr/testify/require"
+	"github.com/tendermint/tendermint/libs/db"
+	"github.com/tendermint/tendermint/libs/log"
 
 	abci "github.com/tendermint/tendermint/abci/types"
 )
@@ -31,3 +37,14 @@ func setGenesis(gapp *GaiaApp, accs ...*auth.BaseAccount) error {
 
 	return nil
 }
+
+func TestGaiadExport(t *testing.T) {
+	db := db.NewMemDB()
+	gapp := NewGaiaApp(log.NewTMLogger(log.NewSyncWriter(os.Stdout)), db, nil)
+	setGenesis(gapp)
+
+	// Making a new app object with the db, so that initchain hasn't been called
+	newGapp := NewGaiaApp(log.NewTMLogger(log.NewSyncWriter(os.Stdout)), db, nil)
+	_, _, err := newGapp.ExportAppStateAndValidators()
+	require.NoError(t, err, "ExportAppStateAndValidators should not have an error")
+}