[Python-checkins] gh-98778: Update HTTPError to initialize properly even if fp is None (gh-99966)

[corona10]

https://github.com/python/cpython/commit/dc8a86893df37e137cfe992e95e7d66cd68e9eaf
commit: dc8a86893df37e137cfe992e95e7d66cd68e9eaf
branch: main
author: Dong-hee Na <donghee.na at python.org>
committer: corona10 <donghee.na92 at gmail.com>
date: 2022-12-08T11:20:34+09:00
summary:

gh-98778: Update HTTPError to initialize properly even if fp is None (gh-99966)

files:
A Misc/NEWS.d/next/Library/2022-12-03-20-06-16.gh-issue-98778.t5U9uc.rst
M Lib/test/test_urllib2.py
M Lib/urllib/error.py

diff --git a/Lib/test/test_urllib2.py b/Lib/test/test_urllib2.py
index 28f88412fdca..498c0382d213 100644
--- a/Lib/test/test_urllib2.py
+++ b/Lib/test/test_urllib2.py
@@ -1824,6 +1824,10 @@ def test_HTTPError_interface(self):
         expected_errmsg = '<HTTPError %s: %r>' % (err.code, err.msg)
         self.assertEqual(repr(err), expected_errmsg)
 
+    def test_gh_98778(self):
+        x = urllib.error.HTTPError("url", 405, "METHOD NOT ALLOWED", None, None)
+        self.assertEqual(getattr(x, "__notes__", ()), ())
+
     def test_parse_proxy(self):
         parse_proxy_test_cases = [
             ('proxy.example.com',
diff --git a/Lib/urllib/error.py b/Lib/urllib/error.py
index 8cd901f13f8e..feec0e7f848e 100644
--- a/Lib/urllib/error.py
+++ b/Lib/urllib/error.py
@@ -10,7 +10,7 @@
 an application may want to handle an exception like a regular
 response.
 """
-
+import io
 import urllib.response
 
 __all__ = ['URLError', 'HTTPError', 'ContentTooShortError']
@@ -42,12 +42,9 @@ def __init__(self, url, code, msg, hdrs, fp):
         self.hdrs = hdrs
         self.fp = fp
         self.filename = url
-        # The addinfourl classes depend on fp being a valid file
-        # object.  In some cases, the HTTPError may not have a valid
-        # file object.  If this happens, the simplest workaround is to
-        # not initialize the base classes.
-        if fp is not None:
-            self.__super_init(fp, hdrs, url, code)
+        if fp is None:
+            fp = io.StringIO()
+        self.__super_init(fp, hdrs, url, code)
 
     def __str__(self):
         return 'HTTP Error %s: %s' % (self.code, self.msg)
diff --git a/Misc/NEWS.d/next/Library/2022-12-03-20-06-16.gh-issue-98778.t5U9uc.rst b/Misc/NEWS.d/next/Library/2022-12-03-20-06-16.gh-issue-98778.t5U9uc.rst
new file mode 100644
index 000000000000..b1c170dff3ea
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-12-03-20-06-16.gh-issue-98778.t5U9uc.rst
@@ -0,0 +1,2 @@
+Update :exc:`~urllib.error.HTTPError` to be initialized properly, even if
+the ``fp`` is ``None``. Patch by Dong-hee Na.