Merge pull request Workiva#159 from matthinrichsen-wf/fix_augmented_interval_tree

Patch Panic on Augmented Interval Tree Traverse

Author: dustinhiatt-wf

augmentedtree/atree.go

@@ -121,13 +121,15 @@ func (t *tree) Traverse(fn func(id Interval)) {
 
 	for len(nodes) != 0 {
 		c := nodes[len(nodes)-1]
-		fn(c.interval)
 		nodes = nodes[:len(nodes)-1]
-		if c.children[0] != nil {
-			nodes = append(nodes, c.children[0])
-		}
-		if c.children[1] != nil {
-			nodes = append(nodes, c.children[1])
+		if c != nil {
+			fn(c.interval)
+			if c.children[0] != nil {
+				nodes = append(nodes, c.children[0])
+			}
+			if c.children[1] != nil {
+				nodes = append(nodes, c.children[1])
+			}
 		}
 	}
 }

augmentedtree/atree_test.go

@@ -625,6 +625,11 @@ func TestInsertDuplicateIntervalChildren(t *testing.T) {
 
 func TestTraverse(t *testing.T) {
 	tree := newTree(1)
+
+	tree.Traverse(func(i Interval) {
+		assert.Fail(t, `traverse should not be called for empty tree`)
+	})
+
 	top := 30
 	for i := 0; i <= top; i++ {
 		tree.Add(constructSingleDimensionInterval(int64(i*10), int64((i+1)*10), uint64(i)))