May 21, 2025 · May 21, 2025 · May 21, 2025 · May 21, 2025 · May 21, 2025 · May 21, 2025
diff --git a/Lib/email/_parseaddr.py b/Lib/email/_parseaddr.py
    # calls for a two-digit yy, but RFC 2822 (which obsoletes RFC 822)
    # mandates a 4-digit yy. For more information, see the documentation for
    # the time module.
    if yy < 100:
    iflen(str(yy)) >= 2 andyy < 100:
        # The year is between 1969 and 1999 (inclusive).
        if yy > 68:
            yy += 1900
diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py

        """
        self.assertEqual(utils.parsedate_tz('25 Feb 03 13:47:26 -0800'),
                         utils.parsedate_tz('25 Feb2003 13:47:26 -0800'))
                         utils.parsedate_tz('25 Feb3 13:47:26 -0800'))
        self.assertEqual(utils.parsedate_tz('25 Feb 71 13:47:26 -0800'),
                         utils.parsedate_tz('25 Feb 1971 13:47:26 -0800'))

diff --git a/Lib/test/test_email/test_parsedate_to_datetime.py b/Lib/test/test_email/test_parsedate_to_datetime.py
 # Test to see if parsedate_to_datetime returns the correct year for different digit numbers, adhering to the RFC2822 spec

 import unittest
 from email.utils import parsedate_to_datetime

 class ParsedateToDatetimeTest(unittest.TestCase):
    def test(self):
        expectations = {
            "Sat, 15 Aug 0001 23:12:09 +0500": "0001",
            "Thu, 1 Sep 1 23:12:09 +0800": "0001",
            "Thu, 7 Oct 123 23:12:09 +0500": "0123",
        }
        for input_string, output_string in expectations.items():
            self.assertEqual(str(parsedate_to_datetime(input_string))[:4], output_string)

 if __name__ == '__main__':
    unittest.main()
diff --git a/Misc/NEWS.d/next/Library/2025-05-21-15-32-04.gh-issue-126845.QhEGg6.rst b/Misc/NEWS.d/next/Library/2025-05-21-15-32-04.gh-issue-126845.QhEGg6.rst
 Fixed _parsedate_tz to not evaluate 1 digit years as as 4-digit years, adhering to RFC 2855 4.3
 Contributed by Gustaf Gyllensporre.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -149,7 +149,7 @@ def _parsedate_tz(data):
		# calls for a two-digit yy, but RFC 2822 (which obsoletes RFC 822)
		# mandates a 4-digit yy. For more information, see the documentation for
		# the time module.
		if yy < 100:
		iflen(str(yy)) >= 2 andyy < 100:
Copy link Member encukouJun 10, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. `yy` is now a number, so if`yy < 100` (and it's positive),`len(str(yy)) >= 2` is never true. You need to keep the original year string for this check.
		# The year is between 1969 and 1999 (inclusive).
		if yy > 68:
		yy += 1900
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -3227,7 +3227,7 @@ def test_parsedate_y2k(self):

		"""
		self.assertEqual(utils.parsedate_tz('25 Feb 03 13:47:26 -0800'),
		utils.parsedate_tz('25 Feb2003 13:47:26 -0800'))
		utils.parsedate_tz('25 Feb3 13:47:26 -0800'))
Copy link Member encukouJun 10, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. This makes the test ineffective.
		self.assertEqual(utils.parsedate_tz('25 Feb 71 13:47:26 -0800'),
		utils.parsedate_tz('25 Feb 1971 13:47:26 -0800'))

Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,17 @@
		# Test to see if parsedate_to_datetime returns the correct year for different digit numbers, adhering to the RFC2822 spec

		import unittest
		from email.utils import parsedate_to_datetime

		class ParsedateToDatetimeTest(unittest.TestCase):
Copy link Member bitdancerJun 10, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. parsedate_to_datetime tests belong in test_utils in DateTimeTests. (Those tests could maybe use some refactoring, but let's ignore that ;)
		def test(self):
		expectations = {
		"Sat, 15 Aug 0001 23:12:09 +0500": "0001",
		"Thu, 1 Sep 1 23:12:09 +0800": "0001",
Copy link Member bitdancerJun 10, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Logically when doing a Postel "be generous in what you accept" recovery here, a single digit year should be treated as if it were a two digit year, which means the result here should 2001, which is what the current code produces.
		"Thu, 7 Oct 123 23:12:09 +0500": "0123",
Copy link Member bitdancerJun 10, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. And this result should be 2023, per the rfc text you quoted (three digit years get 1900 added). I have no idea why that settled on that logic, it makes no sense to me, but that's what the RFC says.
		}
		for input_string, output_string in expectations.items():
Copy link Member bitdancerJun 10, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. subTest would be good here.
		self.assertEqual(str(parsedate_to_datetime(input_string))[:4], output_string)

		if __name__ == '__main__':
		unittest.main()
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Fixed _parsedate_tz to not evaluate 1 digit years as as 4-digit years, adhering to RFC 2855 4.3
		Contributed by Gustaf Gyllensporre.