fix: rootKey empty check by len equals 0 (#801)

Co-authored-by: Marko <marbar3778@yahoo.com>
(cherry picked from commit 06f5be1)

# Conflicts:
#	CHANGELOG.md
#	iterator.go
#	iterator_test.go

CHANGELOG.md

@@ -2,4 +2,48 @@
 
 ## Unreleased
 
+<<<<<<< HEAD
+=======
+### Improvements
+
+- [#703](https://github.com/cosmos/iavl/pull/703) New APIs `NewCompressExporter`/`NewCompressImporter` to support more compact snapshot format.
+- [#729](https://github.com/cosmos/iavl/pull/729) Speedup Genesis writes for IAVL, by writing in small batches.
+- [#726](https://github.com/cosmos/iavl/pull/726) Make `KVPair` and `ChangeSet` serializable with protobuf.
+- [#718](https://github.com/cosmos/iavl/pull/718) Fix `traverseNodes` unexpected behaviour
+- [#770](https://github.com/cosmos/iavl/pull/770) Add `WorkingVersion()int64` API.
+
+### Bug Fixes
+
+- [#773](https://github.com/cosmos/iavl/pull/773) Fix memory leak in `Import`.
+- [#795](https://github.com/cosmos/iavl/pull/795) Fix plugin used for buf generate.
+- [#801](https://github.com/cosmos/iavl/pull/801) Fix rootKey empty check by len equals 0.
+
+### Breaking Changes
+
+- [#735](https://github.com/cosmos/iavl/pull/735) Pass logger to `NodeDB`, `MutableTree` and `ImmutableTree`
+
+- [#646](https://github.com/cosmos/iavl/pull/646) Remove the `orphans` from the storage
+
+- [#777](https://github.com/cosmos/iavl/pull/777) Don't return errors from ImmutableTree.Hash, NewImmutableTree, NewImmutableTreeWIthOpts
+
+### API Changes
+
+- [#646](https://github.com/cosmos/iavl/pull/646) Remove the `DeleteVersion`, `DeleteVersions`, `DeleteVersionsRange` and introduce a new endpoint of `DeleteVersionsTo` instead
+- [#695](https://github.com/cosmos/iavl/pull/695) Add API `SaveChangeSet` to save the changeset as a new version.
+
+## 0.20.0 (March 14, 2023)
+
+### Breaking Changes
+
+- [#586](https://github.com/cosmos/iavl/pull/586) Remove the `RangeProof` and refactor the ics23_proof to use the internal methods.
+
+## 0.19.5 (Februrary 23, 2022)
+
+### Breaking Changes
+
+- [#622](https://github.com/cosmos/iavl/pull/622) `export/newExporter()` and `ImmutableTree.Export()` returns error for nil arguements
+
+- [#640](https://github.com/cosmos/iavl/pull/640) commit `NodeDB` batch in `LoadVersionForOverwriting`.
+- [#636](https://github.com/cosmos/iavl/pull/636) Speed up rollback method: `LoadVersionForOverwriting`.
+>>>>>>> 06f5be1 (fix: rootKey empty check by len equals 0 (#801))
 - [#654](https://github.com/cosmos/iavl/pull/654) Add API `TraverseStateChanges` to extract state changes from iavl versions.

iterator.go

@@ -268,8 +268,13 @@ type NodeIterator struct {
 }
 
 // NewNodeIterator returns a new NodeIterator to traverse the tree of the root node.
+<<<<<<< HEAD
 func NewNodeIterator(root []byte, ndb *nodeDB) (*NodeIterator, error) {
 	if len(root) == 0 {
+=======
+func NewNodeIterator(rootKey []byte, ndb *nodeDB) (*NodeIterator, error) {
+	if len(rootKey) == 0 {
+>>>>>>> 06f5be1 (fix: rootKey empty check by len equals 0 (#801))
 		return &NodeIterator{
 			nodesToVisit: []*Node{},
 			ndb:          ndb,

iterator_test.go

@@ -330,3 +330,52 @@ func setupUnsavedFastIterator(t *testing.T, config *iteratorTestConfig) (dbm.Ite
 	itr := NewUnsavedFastIterator(config.startIterate, config.endIterate, config.ascending, tree.ndb, tree.unsavedFastNodeAdditions, tree.unsavedFastNodeRemovals)
 	return itr, mirror
 }
+<<<<<<< HEAD
+=======
+
+func TestNodeIterator_Success(t *testing.T) {
+	tree, mirror := getRandomizedTreeAndMirror(t)
+
+	_, _, err := tree.SaveVersion()
+	require.NoError(t, err)
+
+	randomizeTreeAndMirror(t, tree, mirror)
+
+	_, _, err = tree.SaveVersion()
+	require.NoError(t, err)
+
+	// check if the iterating count is same with the entire node count of the tree
+	itr, err := NewNodeIterator(tree.root.GetKey(), tree.ndb)
+	require.NoError(t, err)
+	nodeCount := 0
+	for ; itr.Valid(); itr.Next(false) {
+		nodeCount++
+	}
+	require.Equal(t, int64(nodeCount), tree.Size()*2-1)
+
+	// check if the skipped node count is right
+	itr, err = NewNodeIterator(tree.root.GetKey(), tree.ndb)
+	require.NoError(t, err)
+	updateCount := 0
+	skipCount := 0
+	for itr.Valid() {
+		node := itr.GetNode()
+		updateCount++
+		if node.nodeKey.version < tree.Version() {
+			skipCount += int(node.size*2 - 2) // the size of the subtree without the root
+		}
+		itr.Next(node.nodeKey.version < tree.Version())
+	}
+	require.Equal(t, nodeCount, updateCount+skipCount)
+}
+
+func TestNodeIterator_WithEmptyRoot(t *testing.T) {
+	itr, err := NewNodeIterator(nil, newNodeDB(dbm.NewMemDB(), 0, nil, log.NewNopLogger()))
+	require.NoError(t, err)
+	require.False(t, itr.Valid())
+
+	itr, err = NewNodeIterator([]byte{}, newNodeDB(dbm.NewMemDB(), 0, nil, log.NewNopLogger()))
+	require.NoError(t, err)
+	require.False(t, itr.Valid())
+}
+>>>>>>> 06f5be1 (fix: rootKey empty check by len equals 0 (#801))