Fix normalizer crash on comments after line continuations

AUTHORS.txt

@@ -55,4 +55,6 @@ Batuhan Taskaya (@isidentical) <isidentical@gmail.com>
 Jocelyn Boullier (@Kazy) <jocelyn@boullier.bzh>
 
 
+eunwoo song (@be-student)
+
 Note: (@user) means a github user name.

CHANGELOG.rst

@@ -6,6 +6,8 @@ Changelog
 Unreleased
 ++++++++++
 
+- Fix a PEP8 normalizer crash on comments following a line continuation.
+
 0.8.7 (2026-05-02)
 ++++++++++++++++++
 

parso/python/pep8.py

@@ -444,7 +444,9 @@ def _visit_part(self, part, spacing, leaf):
                         should_be_indentation = n.indentation
 
                         self._last_indentation_tos = n
-                        if n == node:
+                        # A continuation in this prefix can make node newer
+                        # than the saved stack. Always stop at its root.
+                        if n == node or n.parent is None:
                             break
                         n = n.parent
 

test/test_pep8.py

@@ -1,3 +1,5 @@
+import pytest
+
 import parso
 
 
@@ -40,3 +42,12 @@ def test_shebang():
     assert not issues('#!\n')
     assert not issues('#!/foo\n')
     assert not issues('#! python\n')
+
+
+@pytest.mark.parametrize('newline', ['\n', '\r\n', '\r'])
+@pytest.mark.parametrize('prefix', ['', 'x = 1\n', 'if True:\n    pass\n'])
+@pytest.mark.parametrize('comment', ['#', '# comment', '# comment\n'])
+def test_comment_after_line_continuation(newline, prefix, comment):
+    code = prefix + '\\' + newline + comment
+    found = issues(code)
+    assert (292 in [issue.code for issue in found]) == (not code.endswith('\n'))