Fix error recovery for multi line strings at the end of the file

parso/python/parser.py

@@ -126,8 +126,8 @@ class Parser(BaseParser):
 
         if self._start_nonterminal == 'file_input' and \
                 (token.type == PythonTokenTypes.ENDMARKER
-                 or token.type == DEDENT and '\n' not in last_leaf.value
-                 and '\r' not in last_leaf.value):
+                 or token.type == DEDENT and not last_leaf.value.endswith('\n')
+                 and not last_leaf.value.endswith('\r')):
             # In Python statements need to end with a newline. But since it's
             # possible (and valid in Python) that there's no newline at the
             # end of a file, we have to recover even if the user doesn't want

test/test_diff_parser.py

@@ -1509,3 +1509,18 @@ def test_async_func2(differ):
         ''')
     differ.initialize(code1)
     differ.parse(code2, parsers=2, copies=1, expect_error_leaves=True)
+
+
+def test_weird_ending(differ):
+    code1 = dedent('''\
+        def foo():
+            a
+            return
+        ''')
+    code2 = dedent('''\
+        def foo():
+            a
+           nonlocal xF"""
+        y"""''')
+    differ.initialize(code1)
+    differ.parse(code2, parsers=1, copies=1, expect_error_leaves=True)