From 69d8c6f5e6d1541357d7e829b2b5a248b4ddc3e5 Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Wed, 23 May 2018 15:41:16 -0700
Subject: [PATCH] Check that language is present in both parse() and resume()

---
 src/runtime/parser.c        | 1 +
 test/runtime/parser_test.cc | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/src/runtime/parser.c b/src/runtime/parser.c
index efde7830..dcb55a62 100644
--- a/src/runtime/parser.c
+++ b/src/runtime/parser.c
@@ -1440,6 +1440,7 @@ TSTree *ts_parser_resume(TSParser *self) {
 }
 
 TSTree *ts_parser_parse(TSParser *self, const TSTree *old_tree, TSInput input) {
+  if (!self->language) return NULL;
   ts_parser__start(self, input, old_tree ? old_tree->root : NULL);
   return ts_parser_resume(self);
 }
diff --git a/test/runtime/parser_test.cc b/test/runtime/parser_test.cc
index 9599563d..7c9e786f 100644
--- a/test/runtime/parser_test.cc
+++ b/test/runtime/parser_test.cc
@@ -568,6 +568,15 @@ describe("Parser", [&]() {
       AssertThat(ts_parser_set_language(parser, &language), IsFalse());
       AssertThat(ts_parser_language(parser), Equals<const TSLanguage *>(nullptr));
     });
+
+    it("does nothing when parse is called while the language is null", [&]() {
+      tree = ts_parser_parse_string(parser, nullptr, "{}", 2);
+      AssertThat(tree, Equals<TSTree *>(nullptr));
+
+      ts_parser_set_language(parser, nullptr);
+      tree = ts_parser_parse_string(parser, nullptr, "{}", 2);
+      AssertThat(tree, Equals<TSTree *>(nullptr));
+    });
   });
 
   describe("set_logger(TSLogger)", [&]() {