From 7064ecf3fb1144e9bc83cd0968fc4b77102341d9 Mon Sep 17 00:00:00 2001
From: Dave Halter <davidhalter88@gmail.com>
Date: Thu, 12 Jul 2018 08:53:48 +0200
Subject: [PATCH] Don't use invalid escape sequences in regex, see
 https://github.com/davidhalter/jedi-vim/issues/843

---
 parso/python/pep8.py | 6 +++---
 parso/python/tree.py | 2 +-
 parso/utils.py       | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/parso/python/pep8.py b/parso/python/pep8.py
index 59fe452..2a037f9 100644
--- a/parso/python/pep8.py
+++ b/parso/python/pep8.py
@@ -391,11 +391,11 @@ class PEP8Normalizer(ErrorFinder):
                 if value.lstrip('#'):
                     self.add_issue(part, 266, "Too many leading '#' for block comment.")
             elif self._on_newline:
-                if not re.match('#:? ', value) and not value == '#' \
+                if not re.match(r'#:? ', value) and not value == '#' \
                         and not (value.startswith('#!') and part.start_pos == (1, 0)):
                     self.add_issue(part, 265, "Block comment should start with '# '")
             else:
-                if not re.match('#:? [^ ]', value):
+                if not re.match(r'#:? [^ ]', value):
                     self.add_issue(part, 262, "Inline comment should start with '# '")
 
             self._reset_newlines(spacing, leaf, is_comment=True)
@@ -677,7 +677,7 @@ class PEP8Normalizer(ErrorFinder):
         elif typ == 'string':
             # Checking multiline strings
             for i, line in enumerate(leaf.value.splitlines()[1:]):
-                indentation = re.match('[ \t]*', line).group(0)
+                indentation = re.match(r'[ \t]*', line).group(0)
                 start_pos = leaf.line + i, len(indentation)
                 # TODO check multiline indentation.
         elif typ == 'endmarker':
diff --git a/parso/python/tree.py b/parso/python/tree.py
index 294ddfe..24d0caa 100644
--- a/parso/python/tree.py
+++ b/parso/python/tree.py
@@ -252,7 +252,7 @@ class String(Literal):
 
     @property
     def string_prefix(self):
-        return re.match('\w*(?=[\'"])', self.value).group(0)
+        return re.match(r'\w*(?=[\'"])', self.value).group(0)
 
     def _get_payload(self):
         match = re.search(
diff --git a/parso/utils.py b/parso/utils.py
index a4801b9..8b9fb16 100644
--- a/parso/utils.py
+++ b/parso/utils.py
@@ -45,7 +45,7 @@ def split_lines(string, keepends=False):
             lst.append('')
         return lst
     else:
-        return re.split('\n|\r\n', string)
+        return re.split(r'\n|\r\n', string)
 
 
 def python_bytes_to_unicode(source, encoding='utf-8', errors='strict'):