Fix a nasty issue in the tokenizer. Fixes #836.

At the same time there was a related issue of not cleaning up newlines properly.

jedi/parser/__init__.py

@@ -232,14 +232,11 @@ class Parser(object):
                         # If there's a statement that fails to be parsed, there
                         # will be no previous leaf. So just ignore it.
                         break
-                elif newline.value != '\n':
-                    # TODO REMOVE, error recovery was simplified.
-                    # This may happen if error correction strikes and removes
-                    # a whole statement including '\n'.
-                    break
                 else:
-                    newline.value = ''
+                    assert newline.value.endswith('\n')
+                    newline.value = newline.value[:-1]
                     endmarker.start_pos = newline.start_pos
+                    break
 
 
 class ParserWithRecovery(Parser):

jedi/parser/tokenize.py

@@ -259,8 +259,7 @@ def generate_tokens(readline, use_exact_op_types=False):
                     # line is an error token.
                     txt = line[pos:]
                 yield TokenInfo(ERRORTOKEN, txt, (lnum, pos), prefix)
-                pos += 1
-                continue
+                break
 
             prefix = additional_prefix + pseudomatch.group(1)
             additional_prefix = ''

test/test_parser/test_diff_parser.py

@@ -206,6 +206,11 @@ def test_open_parentheses(differ):
     differ.parse('isinstance()\n' + func, parsers=2, copies=1)
 
 
+def test_open_parentheses_at_end(differ):
+    code = "a['"
+    differ.initialize(code)
+    differ.parse(code, parsers=1, expect_error_leaves=True)
+
 def test_backslash(differ):
     src = dedent(r"""
     a = 1\

test/test_parser/test_tokenize.py

@@ -3,8 +3,6 @@
 from io import StringIO
 from textwrap import dedent
 
-import pytest
-
 from jedi._compatibility import u, is_py3, py_version
 from jedi.parser.token import NAME, OP, NEWLINE, STRING, INDENT
 from jedi.parser import ParserWithRecovery, load_grammar, tokenize
@@ -12,6 +10,9 @@ from jedi.parser import ParserWithRecovery, load_grammar, tokenize
 
 from ..helpers import unittest
 
+def _get_token_list(string):
+    io = StringIO(u(string))
+    return list(tokenize.generate_tokens(io.readline))
 
 class TokenTest(unittest.TestCase):
     def test_end_pos_one_line(self):
@@ -135,9 +136,7 @@ def test_ur_literals():
     - All the other Python versions work very well with it.
     """
     def check(literal, is_literal=True):
-        io = StringIO(u(literal))
-        tokens = tokenize.generate_tokens(io.readline)
-        token_list = list(tokens)
+        token_list = _get_token_list(literal)
         typ, result_literal, _, _ = token_list[0]
         if is_literal:
             assert typ == STRING
@@ -158,3 +157,19 @@ def test_ur_literals():
     check('rF""', is_literal=py_version >= 36)
     check('f""', is_literal=py_version >= 36)
     check('F""', is_literal=py_version >= 36)
+
+
+def test_error_literal():
+    error_token, endmarker = _get_token_list('"\n')
+    assert error_token.type == tokenize.ERRORTOKEN
+    assert endmarker.prefix == ''
+    assert error_token.string == '"\n'
+    assert endmarker.type == tokenize.ENDMARKER
+    assert endmarker.prefix == ''
+
+    bracket, error_token, endmarker = _get_token_list('( """')
+    assert error_token.type == tokenize.ERRORTOKEN
+    assert error_token.prefix == ' '
+    assert error_token.string == '"""'
+    assert endmarker.type == tokenize.ENDMARKER
+    assert endmarker.prefix == ''