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bpo-36959: Fix error messages for invalid ISO format string in _strptime() (GH-13408) 

Previously some error messages complained about incompatible
combinations of directives that are not contained in the format string.

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
This commit is contained in:
Gordon P. Hemsley 2023-12-26 14:26:17 -05:00 committed by GitHub
parent e5cce70df7
commit 4b2c3e8e43
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 63 additions and 42 deletions
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27
Lib/_strptime.py
View File

@ -342,8 +342,6 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
tz = -1
gmtoff = None
gmtoff_fraction = 0
# Default to -1 to signify that values not known; not critical to have,
# though
iso_week = week_of_year = None
week_of_year_start = None
# weekday and julian defaulted to None so as to signal need to calculate
@ -470,17 +468,17 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
# Deal with the cases where ambiguities arise
# don't assume default values for ISO week/year
if year is None and iso_year is not None:
if iso_week is None or weekday is None:
raise ValueError("ISO year directive '%G' must be used with "
"the ISO week directive '%V' and a weekday "
"directive ('%A', '%a', '%w', or '%u').")
if iso_year is not None:
if julian is not None:
raise ValueError("Day of the year directive '%j' is not "
"compatible with ISO year directive '%G'. "
"Use '%Y' instead.")
elif week_of_year is None and iso_week is not None:
if weekday is None:
elif iso_week is None or weekday is None:
raise ValueError("ISO year directive '%G' must be used with "
"the ISO week directive '%V' and a weekday "
"directive ('%A', '%a', '%w', or '%u').")
elif iso_week is not None:
if year is None or weekday is None:
raise ValueError("ISO week directive '%V' must be used with "
"the ISO year directive '%G' and a weekday "
"directive ('%A', '%a', '%w', or '%u').")
@ -490,11 +488,12 @@ def _strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
"instead.")
leap_year_fix = False
if year is None and month == 2 and day == 29:
year = 1904 # 1904 is first leap year of 20th century
leap_year_fix = True
elif year is None:
year = 1900
if year is None:
if month == 2 and day == 29:
year = 1904 # 1904 is first leap year of 20th century
leap_year_fix = True
else:
year = 1900
# If we know the week of the year and what day of that week, we can figure
# out the Julian day of the year.

76
Lib/test/test_strptime.py
View File

@ -224,35 +224,55 @@ class StrptimeTests(unittest.TestCase):
else:
self.fail("'%s' did not raise ValueError" % bad_format)
# Ambiguous or incomplete cases using ISO year/week/weekday directives
# 1. ISO week (%V) is specified, but the year is specified with %Y
# instead of %G
with self.assertRaises(ValueError):
_strptime._strptime("1999 50", "%Y %V")
# 2. ISO year (%G) and ISO week (%V) are specified, but weekday is not
with self.assertRaises(ValueError):
_strptime._strptime("1999 51", "%G %V")
# 3. ISO year (%G) and weekday are specified, but ISO week (%V) is not
for w in ('A', 'a', 'w', 'u'):
with self.assertRaises(ValueError):
_strptime._strptime("1999 51","%G %{}".format(w))
# 4. ISO year is specified alone (e.g. time.strptime('2015', '%G'))
with self.assertRaises(ValueError):
_strptime._strptime("2015", "%G")
# 5. Julian/ordinal day (%j) is specified with %G, but not %Y
with self.assertRaises(ValueError):
_strptime._strptime("1999 256", "%G %j")
# 6. Invalid ISO weeks
invalid_iso_weeks = [
"2019-00-1",
"2019-54-1",
"2021-53-1",
]
for invalid_iso_dtstr in invalid_iso_weeks:
with self.subTest(invalid_iso_dtstr):
with self.assertRaises(ValueError):
_strptime._strptime(invalid_iso_dtstr, "%G-%V-%u")
msg_week_no_year_or_weekday = r"ISO week directive '%V' must be used with " \
r"the ISO year directive '%G' and a weekday directive " \
r"\('%A', '%a', '%w', or '%u'\)."
msg_week_not_compatible = r"ISO week directive '%V' is incompatible with " \
r"the year directive '%Y'. Use the ISO year '%G' instead."
msg_julian_not_compatible = r"Day of the year directive '%j' is not " \
r"compatible with ISO year directive '%G'. Use '%Y' instead."
msg_year_no_week_or_weekday = r"ISO year directive '%G' must be used with " \
r"the ISO week directive '%V' and a weekday directive " \
r"\('%A', '%a', '%w', or '%u'\)."
locale_time = _strptime.LocaleTime()
# Ambiguous or incomplete cases using ISO year/week/weekday directives
subtests = [
# 1. ISO week (%V) is specified, but the year is specified with %Y
# instead of %G
("1999 50", "%Y %V", msg_week_no_year_or_weekday),
("1999 50 5", "%Y %V %u", msg_week_not_compatible),
# 2. ISO year (%G) and ISO week (%V) are specified, but weekday is not
("1999 51", "%G %V", msg_year_no_week_or_weekday),
# 3. ISO year (%G) and weekday are specified, but ISO week (%V) is not
("1999 {}".format(locale_time.f_weekday[5]), "%G %A",
msg_year_no_week_or_weekday),
("1999 {}".format(locale_time.a_weekday[5]), "%G %a",
msg_year_no_week_or_weekday),
("1999 5", "%G %w", msg_year_no_week_or_weekday),
("1999 5", "%G %u", msg_year_no_week_or_weekday),
# 4. ISO year is specified alone (e.g. time.strptime('2015', '%G'))
("2015", "%G", msg_year_no_week_or_weekday),
# 5. Julian/ordinal day (%j) is specified with %G, but not %Y
("1999 256", "%G %j", msg_julian_not_compatible),
("1999 50 5 256", "%G %V %u %j", msg_julian_not_compatible),
# ISO week specified alone
("50", "%V", msg_week_no_year_or_weekday),
# ISO year is unspecified, falling back to year
("50 5", "%V %u", msg_week_no_year_or_weekday),
# 6. Invalid ISO weeks
("2019-00-1", "%G-%V-%u",
"time data '2019-00-1' does not match format '%G-%V-%u'"),
("2019-54-1", "%G-%V-%u",
"time data '2019-54-1' does not match format '%G-%V-%u'"),
("2021-53-1", "%G-%V-%u", "Invalid week: 53"),
]
for (data_string, format, message) in subtests:
with self.subTest(data_string=data_string, format=format):
with self.assertRaisesRegex(ValueError, message):
_strptime._strptime(data_string, format)
def test_strptime_exception_context(self):
# check that this doesn't chain exceptions needlessly (see #17572)

2
Misc/NEWS.d/next/Library/2019-05-18-15-50-14.bpo-36959.ew6WZ4.rst Normal file
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@ -0,0 +1,2 @@
Fix some error messages for invalid ISO format string combinations in ``strptime()`` that referred to directives not contained in the format string.
Patch by Gordon P. Hemsley.