gh-153406: Raise ValueError, not OverflowError, for out-of-range dates in email.utils...

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.

diff --git a/Lib/email/utils.py b/Lib/email/utils.py
index 7aefc24c15dc767d784d1b4358d455e1c886e640..6889c5591bf0306da9f341eb4f751fae924bc9b6 100644 (file)
--- a/Lib/email/utils.py
+++ b/Lib/email/utils.py
@@ -324,10 +324,13 @@ 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 aa918255d15c37e2ed0f9a232488257aeb4b10fa..c118fd5e20d048f4aabad5b59d4fbeaed585cfb5 100644 (file)
--- a/Lib/test/test_email/test_headerregistry.py
+++ b/Lib/test/test_email/test_headerregistry.py
@@ -221,6 +221,14 @@ class TestDateHeader(TestHeaderBase):
         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 c9d09098b502f9d2fab3dbda2195730c0029762e..86d1bfff891a7e67b0c413ff6c75556c9045a6bd 100644 (file)
--- a/Lib/test/test_email/test_utils.py
+++ b/Lib/test/test_email/test_utils.py
@@ -77,6 +77,15 @@ class DateTimeTests(unittest.TestCase):
             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 (file)
index 0000000..c095757
--- /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.