From df3969e9d9f02576c743fc25cad8c607ecb6f503 Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Tue, 10 Jul 2018 14:00:31 -0700
Subject: [PATCH] Invalidate tree's parent cache after an edit

---
 src/runtime/tree.c        |  2 ++
 test/runtime/node_test.cc | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/src/runtime/tree.c b/src/runtime/tree.c
index 1345f065..16b5a18b 100644
--- a/src/runtime/tree.c
+++ b/src/runtime/tree.c
@@ -41,6 +41,8 @@ const TSLanguage *ts_tree_language(const TSTree *self) {
 void ts_tree_edit(TSTree *self, const TSInputEdit *edit) {
   SubtreePool pool = ts_subtree_pool_new(0);
   self->root = ts_subtree_edit(self->root, edit, &pool);
+  self->parent_cache_start = 0;
+  self->parent_cache_size = 0;
   ts_subtree_pool_delete(&pool);
 }
 
diff --git a/test/runtime/node_test.cc b/test/runtime/node_test.cc
index 54f21c5f..1b953351 100644
--- a/test/runtime/node_test.cc
+++ b/test/runtime/node_test.cc
@@ -1,3 +1,4 @@
+
 #include "test_helper.h"
 #include "runtime/alloc.h"
 #include "helpers/tree_helpers.h"
@@ -543,6 +544,18 @@ describe("Node", [&]() {
       AssertThat(ts_node_parent(node1), Equals(node2));
     });
   });
+
+  describe("parent()", [&]() {
+    it("works after the tree has been edited (regression)", [&]() {
+      TSNode false_node = ts_node_named_child(root_node, 1);
+
+      TSInputEdit edit = {0, 0, 5, {0, 0}, {0, 0}, {5, 0}};
+      ts_tree_edit(tree, &edit);
+
+      TSNode array_node = ts_node_parent(false_node);
+      AssertThat(ts_node_start_point(array_node), Equals<TSPoint>({7, 0}));
+    });
+  });
 });
 
 describe("TreeCursor", [&]() {