chore: new GetLatestVersion api (backport #961) (#962)

Co-authored-by: cool-developer <[email protected]>

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+
+### Improvements
+
+- [#961](https://github.com/cosmos/iavl/pull/961) Add new `GetLatestVersion` API to get the latest version.
 - [#965](https://github.com/cosmos/iavl/pull/965) Use expected interface for expected IAVL `Logger`.
 - [#970](https://github.com/cosmos/iavl/pull/970) Close the pruning process when the nodeDB is closed.
 

mutable_tree.go

@@ -70,6 +70,11 @@ func (tree *MutableTree) IsEmpty() bool {
 	return tree.ImmutableTree.Size() == 0
 }
 
+// GetLatestVersion returns the latest version of the tree.
+func (tree *MutableTree) GetLatestVersion() (int64, error) {
+	return tree.ndb.getLatestVersion()
+}
+
 // VersionExists returns whether or not a version exists.
 func (tree *MutableTree) VersionExists(version int64) bool {
 	legacyLatestVersion, err := tree.ndb.getLegacyLatestVersion()

mutable_tree_test.go

@@ -346,11 +346,15 @@ func prepareTree(t *testing.T) *MutableTree {
 	return newTree
 }
 
-func TestMutableTree_VersionExists(t *testing.T) {
+func TestMutableTree_Version(t *testing.T) {
 	tree := prepareTree(t)
 	require.True(t, tree.VersionExists(1))
 	require.True(t, tree.VersionExists(2))
 	require.False(t, tree.VersionExists(3))
+
+	v, err := tree.GetLatestVersion()
+	require.NoError(t, err)
+	require.Equal(t, int64(2), v)
 }
 
 func checkGetVersioned(t *testing.T, tree *MutableTree, version int64, key, value []byte) {