diff --git a/Lib/_strptime.py b/Lib/_strptime.py index 3884a670b82..d101c6de05d 100644 --- a/Lib/_strptime.py +++ b/Lib/_strptime.py @@ -329,7 +329,7 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"): (bad_directive, format)) from None # IndexError only occurs when the format string is "%" except IndexError: - raise ValueError("stray %% in format '%s'" % format) + raise ValueError("stray %% in format '%s'" % format) from None _regex_cache[format] = format_regex found = format_regex.match(data_string) if not found: diff --git a/Lib/test/test_strptime.py b/Lib/test/test_strptime.py index 68e6a676363..d5bc39d0dd3 100644 --- a/Lib/test/test_strptime.py +++ b/Lib/test/test_strptime.py @@ -223,6 +223,10 @@ class StrptimeTests(unittest.TestCase): with self.assertRaises(ValueError) as e: _strptime._strptime_time('', '%D') self.assertIs(e.exception.__suppress_context__, True) + # additional check for IndexError branch (issue #19545) + with self.assertRaises(ValueError) as e: + _strptime._strptime_time('19', '%Y %') + self.assertIs(e.exception.__suppress_context__, True) def test_unconverteddata(self): # Check ValueError is raised when there is unconverted data diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py index f3643b63ffb..44bcb943cba 100644 --- a/Lib/test/test_time.py +++ b/Lib/test/test_time.py @@ -198,6 +198,10 @@ class TimeTestCase(unittest.TestCase): with self.assertRaises(ValueError) as e: time.strptime('', '%D') self.assertIs(e.exception.__suppress_context__, True) + # additional check for IndexError branch (issue #19545) + with self.assertRaises(ValueError) as e: + time.strptime('19', '%Y %') + self.assertIs(e.exception.__suppress_context__, True) def test_asctime(self): time.asctime(time.gmtime(self.t)) diff --git a/Misc/NEWS b/Misc/NEWS index 640a25aa5f2..eabcfb7ef35 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -68,6 +68,9 @@ Core and Builtins Library ------- +- Issue #19545: Avoid chained exceptions while passing stray % to + time.strptime(). Initial patch by Claudiu Popa. + - Issue #3158: doctest can now find doctests in functions and methods written in C.