From cbc693a0a305d6dda40133c929bf9c1547b3a149 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?tonghuaroot=20=28=E7=AB=A5=E8=AF=9D=29?=
 <tonghuaroot@gmail.com>
Date: Thu, 9 Jul 2026 21:58:56 +0800
Subject: [PATCH] gh-153406: Raise ValueError, not OverflowError, for
 out-of-range dates in email.utils.parsedate_to_datetime (GH-153407)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

email.utils.parsedate_to_datetime documented that it raises ValueError for an invalid date, but it leaked OverflowError when the parsed year or timezone offset was too large for the datetime and timedelta constructors, and that OverflowError also escaped the modern header parsing path since DateHeader.parse only caught ValueError. Wrap the datetime and timezone construction so an OverflowError is re-raised as a ValueError with the original chained as the cause, which restores the documented contract and lets the existing header handler record an InvalidDateDefect instead of raising.
(cherry picked from commit 37a26b9b94b147b5d683bfce0ef5a4c2fbc21085)

Co-authored-by: tonghuaroot (童话) <tonghuaroot@gmail.com>
---
 Lib/email/utils.py                                    | 11 +++++++----
 Lib/test/test_email/test_headerregistry.py            |  8 ++++++++
 Lib/test/test_email/test_utils.py                     |  9 +++++++++
 .../2026-07-09-00-00-00.gh-issue-153406.vyMmB6.rst    |  3 +++
 4 files changed, 27 insertions(+), 4 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2026-07-09-00-00-00.gh-issue-153406.vyMmB6.rst

diff --git a/Lib/email/utils.py b/Lib/email/utils.py
index e4d35f06abcc09..c82b82fb9170f6 100644
--- a/Lib/email/utils.py
+++ b/Lib/email/utils.py
@@ -317,10 +317,13 @@ def parsedate_to_datetime(data):
     if parsed_date_tz is None:
         raise ValueError('Invalid date value or format "%s"' % str(data))
     *dtuple, tz = parsed_date_tz
-    if tz is None:
-        return datetime.datetime(*dtuple[:6])
-    return datetime.datetime(*dtuple[:6],
-            tzinfo=datetime.timezone(datetime.timedelta(seconds=tz)))
+    try:
+        if tz is None:
+            return datetime.datetime(*dtuple[:6])
+        return datetime.datetime(*dtuple[:6],
+                tzinfo=datetime.timezone(datetime.timedelta(seconds=tz)))
+    except OverflowError as exc:
+        raise ValueError('Invalid date value or format "%s"' % str(data)) from exc
 
 
 def parseaddr(addr, *, strict=True):
diff --git a/Lib/test/test_email/test_headerregistry.py b/Lib/test/test_email/test_headerregistry.py
index ae29ce3426c016..3da9a495a2334f 100644
--- a/Lib/test/test_email/test_headerregistry.py
+++ b/Lib/test/test_email/test_headerregistry.py
@@ -221,6 +221,14 @@ def test_invalid_date_value(self):
         self.assertEqual(len(h.defects), 1)
         self.assertIsInstance(h.defects[0], errors.InvalidDateDefect)
 
+    def test_out_of_range_date_value(self):
+        s = 'Mon, 20 Nov 9999999999 12:00:00 +0000'
+        h = self.make_header('date', s)
+        self.assertEqual(h, s)
+        self.assertIsNone(h.datetime)
+        self.assertEqual(len(h.defects), 1)
+        self.assertIsInstance(h.defects[0], errors.InvalidDateDefect)
+
     def test_datetime_read_only(self):
         h = self.make_header('date', self.datestring)
         with self.assertRaises(AttributeError):
diff --git a/Lib/test/test_email/test_utils.py b/Lib/test/test_email/test_utils.py
index d04b3909efa643..ff4a03de9f42a0 100644
--- a/Lib/test/test_email/test_utils.py
+++ b/Lib/test/test_email/test_utils.py
@@ -69,6 +69,15 @@ def test_parsedate_to_datetime_with_invalid_raises_valueerror(self):
             with self.subTest(dtstr=dtstr):
                 self.assertRaises(ValueError, utils.parsedate_to_datetime, dtstr)
 
+    def test_parsedate_to_datetime_out_of_range_raises_valueerror(self):
+        out_of_range_dates = [
+            'Mon, 20 Nov 9999999999 12:00:00 +0000',
+            'Mon, 20 Nov 2017 12:00:00 +24000000000000',
+        ]
+        for dtstr in out_of_range_dates:
+            with self.subTest(dtstr=dtstr):
+                self.assertRaises(ValueError, utils.parsedate_to_datetime, dtstr)
+
 class LocaltimeTests(unittest.TestCase):
 
     def test_localtime_is_tz_aware_daylight_true(self):
diff --git a/Misc/NEWS.d/next/Library/2026-07-09-00-00-00.gh-issue-153406.vyMmB6.rst b/Misc/NEWS.d/next/Library/2026-07-09-00-00-00.gh-issue-153406.vyMmB6.rst
new file mode 100644
index 00000000000000..c09575754e3380
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-07-09-00-00-00.gh-issue-153406.vyMmB6.rst
@@ -0,0 +1,3 @@
+:func:`email.utils.parsedate_to_datetime` now raises :exc:`ValueError`
+instead of :exc:`OverflowError` when the parsed year or timezone offset is
+out of range, matching its documented behavior.