test fixes

mutable_tree.go

@@ -361,22 +361,19 @@ func (tree *MutableTree) LoadVersion(targetVersion int64) (int64, error) {
 }
 
 // LoadVersionForOverwriting attempts to load a tree at a previously committed
-// version. Any versions greater than targetVersion will be deleted.
+// version, or the latest version below it. Any versions greater than targetVersion will be deleted.
 func (tree *MutableTree) LoadVersionForOverwriting(targetVersion int64) (int64, error) {
 	latestVersion, err := tree.LoadVersion(targetVersion)
 	if err != nil {
-		return 0, err
-	}
-	if latestVersion != targetVersion {
-		return 0, errors.Errorf("version %v does not exist, found %v", targetVersion, latestVersion)
+		return latestVersion, err
 	}
 
 	if err = tree.ndb.DeleteVersionsFrom(targetVersion + 1); err != nil {
-		return 0, err
+		return latestVersion, err
 	}
 
 	if err = tree.ndb.Commit(); err != nil {
-		return 0, err
+		return latestVersion, err
 	}
 
 	tree.ndb.resetLatestVersion(latestVersion)
@@ -387,7 +384,7 @@ func (tree *MutableTree) LoadVersionForOverwriting(targetVersion int64) (int64,
 		}
 	}
 
-	return targetVersion, nil
+	return latestVersion, nil
 }
 
 // GetImmutable loads an ImmutableTree at a given version for querying. The returned tree is

nodedb.go

@@ -195,8 +195,8 @@ func (ndb *nodeDB) DeleteVersionsFrom(version int64) error {
 	if err != nil {
 		return err
 	}
-	if len(root) == 0 {
-		return errors.New("root for version %v not found")
+	if root == nil {
+		return errors.Errorf("root for version %v not found", latest)
 	}
 
 	for v, r := range ndb.versionReaders {

tree_test.go

@@ -1438,17 +1438,20 @@ func TestLoadVersionForOverwritingCase2(t *testing.T) {
 func TestLoadVersionForOverwritingCase3(t *testing.T) {
 	require := require.New(t)
 
-	tree, _ := NewMutableTreeWithOpts(db.NewMemDB(), 0, nil)
+	tree, err := NewMutableTreeWithOpts(db.NewMemDB(), 0, nil)
+	require.NoError(err)
 
 	for i := byte(0); i < 20; i++ {
 		tree.Set([]byte{i}, []byte{i})
 	}
-	tree.SaveVersion()
+	_, _, err = tree.SaveVersion()
+	require.NoError(err)
 
 	for i := byte(0); i < 20; i++ {
 		tree.Set([]byte{i}, []byte{i + 1})
 	}
-	tree.SaveVersion()
+	_, _, err = tree.SaveVersion()
+	require.NoError(err)
 
 	removedNodes := []*Node{}
 
@@ -1461,12 +1464,14 @@ func TestLoadVersionForOverwritingCase3(t *testing.T) {
 	for i := byte(0); i < 20; i++ {
 		tree.Remove([]byte{i})
 	}
-	tree.SaveVersion()
+	_, _, err = tree.SaveVersion()
+	require.NoError(err)
 
-	_, err := tree.LoadVersionForOverwriting(1)
+	_, err = tree.LoadVersionForOverwriting(1)
 	require.NoError(err)
 	for _, n := range removedNodes {
-		has, _ := tree.ndb.Has(n.hash)
+		has, err := tree.ndb.Has(n.hash)
+		require.NoError(err)
 		require.False(has, "LoadVersionForOverwriting should remove useless nodes")
 	}