Merge pull request #3227 from ruby/pz-regexp-uninit-val

Fix use of uninitialized value when parsing regexp

Author: eileencodes

src/regexp.c

@@ -158,6 +158,11 @@ pm_regexp_parse_range_quantifier(pm_regexp_parser_t *parser) {
     } state = PM_REGEXP_RANGE_QUANTIFIER_STATE_START;
 
     while (1) {
+        if (parser->cursor >= parser->end) {
+            parser->cursor = savepoint;
+            return true;
+        }
+
         switch (state) {
             case PM_REGEXP_RANGE_QUANTIFIER_STATE_START:
                 switch (*parser->cursor) {

test/prism/regexp_test.rb

@@ -186,6 +186,10 @@ def test_fake_range_quantifier_because_of_spaces
       assert_valid_regexp("foo{1, 2}")
     end
 
+    def test_fake_range_quantifier_because_unclosed
+      assert_valid_regexp("\\A{")
+    end
+
     ############################################################################
     # These test that flag values are correct.
     ############################################################################