[Python-checkins] [3.11] gh-107715: Escape class name in regular expression (GH-107716) (GH-107727)

[serhiy-storchaka]

https://github.com/python/cpython/commit/5f36e5ca5fe6768ae639aaf7c04ed41b665880e1
commit: 5f36e5ca5fe6768ae639aaf7c04ed41b665880e1
branch: 3.11
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: serhiy-storchaka <storchaka at gmail.com>
date: 2023-08-12T11:57:49Z
summary:

[3.11] gh-107715: Escape class name in regular expression (GH-107716) (GH-107727)

This patch escapes the class name before embedding it in the regular expression
for `pat` in `doctest.DocTestFinder._find_lineno`. While class names do not
ordinarily contain special characters, it is possible to encounter these when a
class is created dynamically. Escaping the name will correctly return `None` in
this scenario, rather than potentially matching a different class or raising
`re.error` depending on the symbols used.
(cherry picked from commit 85793278793708ad6b7132a54ac9fb4b2c5bcac1)

Co-authored-by: Gertjan van Zwieten <git at gjvz.nl>

files:
A Misc/NEWS.d/next/Library/2023-08-07-14-12-07.gh-issue-107715.238r2f.rst
M Lib/doctest.py

diff --git a/Lib/doctest.py b/Lib/doctest.py
index dafad505ef0e8..8fcb4ee0a02ee 100644
--- a/Lib/doctest.py
+++ b/Lib/doctest.py
@@ -1104,7 +1104,7 @@ def _find_lineno(self, obj, source_lines):
             if source_lines is None:
                 return None
             pat = re.compile(r'^\s*class\s*%s\b' %
-                             getattr(obj, '__name__', '-'))
+                             re.escape(getattr(obj, '__name__', '-')))
             for i, line in enumerate(source_lines):
                 if pat.match(line):
                     lineno = i
diff --git a/Misc/NEWS.d/next/Library/2023-08-07-14-12-07.gh-issue-107715.238r2f.rst b/Misc/NEWS.d/next/Library/2023-08-07-14-12-07.gh-issue-107715.238r2f.rst
new file mode 100644
index 0000000000000..4bf08c071df2f
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-08-07-14-12-07.gh-issue-107715.238r2f.rst
@@ -0,0 +1 @@
+Fix :meth:`doctest.DocTestFinder.find` in presence of class names with special characters. Patch by Gertjan van Zwieten.