From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miro=20Hron=C4=8Dok?= <miro@hroncok.cz>
Date: Fri, 8 Jul 2022 12:19:43 +0200
Subject: [PATCH] 00385: gh-94675: Add a regression test for rjsmin re slowdown

This tests a speed regression in the re module
which prevented chromium from building in Fedora.

https://github.com/python/cpython/pull/94685
---
 Lib/test/test_re.py                           | 31 ++++++++++++++++++-
 ...2-07-08-12-22-00.gh-issue-94675.IiTs5f.rst |  1 +
 2 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Tests/2022-07-08-12-22-00.gh-issue-94675.IiTs5f.rst

diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index ab980793fa..5d946370ee 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -1,6 +1,7 @@
 from test.support import (gc_collect, bigmemtest, _2G,
                           cpython_only, captured_stdout,
-                          check_disallow_instantiation, is_emscripten, is_wasi)
+                          check_disallow_instantiation, is_emscripten, is_wasi,
+                          SHORT_TIMEOUT)
 import locale
 import re
 import string
@@ -11,6 +12,14 @@
 from re import Scanner
 from weakref import proxy
 
+# some platforms lack working multiprocessing
+try:
+    import _multiprocessing
+except ImportError:
+    multiprocessing = None
+else:
+    import multiprocessing
+
 # Misc tests from Tim Peters' re.doc
 
 # WARNING: Don't change details in these tests if you don't know
@@ -2438,6 +2447,26 @@ def test_template_function_and_flag_is_deprecated(self):
         self.assertTrue(template_re1.match('ahoy'))
         self.assertFalse(template_re1.match('nope'))
 
+    @unittest.skipIf(multiprocessing is None, 'test requires multiprocessing')
+    def test_regression_gh94675(self):
+        pattern = re.compile(r'(?<=[({}])(((//[^\n]*)?[\n])([\000-\040])*)*'
+                             r'((/[^/\[\n]*(([^\n]|(\[\n]*(]*)*\]))'
+                             r'[^/\[]*)*/))((((//[^\n]*)?[\n])'
+                             r'([\000-\040]|(/\*[^*]*\*+'
+                             r'([^/*]\*+)*/))*)+(?=[^\000-\040);\]}]))')
+        input_js = '''a(function() {
+            ///////////////////////////////////////////////////////////////////
+        });'''
+        p = multiprocessing.Process(target=pattern.sub, args=('', input_js))
+        p.start()
+        p.join(SHORT_TIMEOUT)
+        try:
+            self.assertFalse(p.is_alive(), 'pattern.sub() timed out')
+        finally:
+            if p.is_alive():
+                p.terminate()
+                p.join()
+
 
 def get_debug_out(pat):
     with captured_stdout() as out:
diff --git a/Misc/NEWS.d/next/Tests/2022-07-08-12-22-00.gh-issue-94675.IiTs5f.rst b/Misc/NEWS.d/next/Tests/2022-07-08-12-22-00.gh-issue-94675.IiTs5f.rst
new file mode 100644
index 0000000000..d0005d9f60
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2022-07-08-12-22-00.gh-issue-94675.IiTs5f.rst
@@ -0,0 +1 @@
+Add a regression test for :mod:`re` exponentional slowdown when using rjsmin.