Update iavl tree and address pr cleanup comments

app/app_test.go

@@ -218,13 +218,13 @@ func TestInitState(t *testing.T) {
 	assert.Equal(unsortCoins, coins)
 
 	err = app.InitState("base", "dslfkgjdas", "")
-	require.NotNil(err)
+	require.Error(err)
 
 	err = app.InitState("", "dslfkgjdas", "")
-	require.NotNil(err)
+	require.Error(err)
 
 	err = app.InitState("dslfkgjdas", "szfdjzs", "")
-	require.NotNil(err)
+	require.Error(err)
 }
 
 // Test CheckTx and DeliverTx with insufficient and sufficient balance

app/store.go

@@ -258,18 +258,12 @@ func loadState(dbName string, cacheSize int, historySize uint64) (*sm.State, err
 	dir := path.Dir(dbPath)
 	name := path.Base(dbPath)
 
-	// Make sure the path exists
-	empty, _ := cmn.IsDirEmpty(dbPath + ".db")
-
 	// Open database called "dir/name.db", if it doesn't exist it will be created
 	db := dbm.NewDB(name, dbm.LevelDBBackendStr, dir)
 	tree := iavl.NewVersionedTree(cacheSize, db)
-
-	if !empty {
 	if err = tree.Load(); err != nil {
 		return nil, errors.ErrInternal("Loading tree: " + err.Error())
 	}
-	}
 
 	return sm.NewState(tree, historySize), nil
 }

glide.lock

@@ -1,5 +1,5 @@
 hash: fa04e2d0e8764d44c0f8e3400d7d12118b0f05aac6c12e5ff0d3dd1940c03100
-updated: 2017-10-19T16:01:35.775869665+02:00
+updated: 2017-10-20T19:33:25.496934736+02:00
 imports:
 - name: github.com/bgentry/speakeasy
   version: 4aabc24848ce5fd31929f7d1e4ea74d3709c14cd
@@ -133,9 +133,9 @@ imports:
   - data
   - data/base58
 - name: github.com/tendermint/iavl
-  version: 4f9a4a2433e3b3022ae2ceec50a1f57689d54145
+  version: 721710e7aa59f61dbfbf558943a207ba3fe6b926
 - name: github.com/tendermint/light-client
-  version: 79125bb4dfe173fe8a7208327ac4ec4c73d1a8a7
+  version: f817693e93241ee10d8ad49935f7c05b4776d829
   subpackages:
   - certifiers
   - certifiers/client
@@ -237,7 +237,7 @@ imports:
   - tap
   - transport
 - name: gopkg.in/go-playground/validator.v9
-  version: d529ee1b0f30352444f507cc6cdac96bfd12decc
+  version: 6d8c18553ea1ac493d049edd6f102f52e618f085
 - name: gopkg.in/yaml.v2
   version: cd8b52f8269e0feb286dfeef29f8fe4d5b397e0b
 testImports:

state/merkle.go

@@ -11,6 +11,8 @@ type State struct {
 	historySize uint64
 }
 
+// NewState wraps a versioned tree and maintains all needed
+// states for the abci app
 func NewState(tree *iavl.VersionedTree, historySize uint64) *State {
 	base := NewBonsai(tree)
 	return &State{
@@ -21,31 +23,47 @@ func NewState(tree *iavl.VersionedTree, historySize uint64) *State {
 	}
 }
 
+// Size is the number of nodes in the last commit
 func (s State) Size() int {
 	return s.committed.Tree.Size()
 }
 
+// IsEmpty is true is no data was ever in the tree
+// (and signals it is unsafe to save)
+func (s State) IsEmpty() bool {
+	return s.committed.Tree.IsEmpty()
+}
+
+// Committed gives us read-only access to the committed
+// state(s), including historical queries
 func (s State) Committed() *Bonsai {
 	return s.committed
 }
 
+// Append gives us read-write access to the current working
+// state (to be committed at EndBlock)
 func (s State) Append() SimpleDB {
 	return s.deliverTx
 }
 
+// Append gives us read-write access to the current scratch
+// state (to be reset at EndBlock)
 func (s State) Check() SimpleDB {
 	return s.checkTx
 }
 
+// LatestHeight is the last block height we have committed
 func (s State) LatestHeight() uint64 {
 	return s.committed.Tree.LatestVersion()
 }
 
+// LatestHash is the root hash of the last state we have
+// committed
 func (s State) LatestHash() []byte {
 	return s.committed.Tree.Hash()
 }
 
-// Commit save persistent nodes to the database and re-copies the trees
+// Commit saves persistent nodes to the database and re-copies the trees
 func (s *State) Commit(version uint64) ([]byte, error) {
 	// commit (if we didn't do hash earlier)
 	err := s.committed.Commit(s.deliverTx)
@@ -55,7 +73,7 @@ func (s *State) Commit(version uint64) ([]byte, error) {
 
 	// store a new version
 	var hash []byte
-	if s.committed.Tree.Size() > 0 || s.committed.Tree.LatestVersion() > 0 {
+	if !s.IsEmpty() {
 		hash, err = s.committed.Tree.SaveVersion(version)
 		if err != nil {
 			return nil, err