gh-41431: Add datetime.time.strptime() and datetime.date.strptime()

Include/internal/pycore_global_strings.h

@@ -267,7 +267,9 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(_shutdown)
         STRUCT_FOR_ID(_slotnames)
         STRUCT_FOR_ID(_strptime)
-        STRUCT_FOR_ID(_strptime_datetime)
+        STRUCT_FOR_ID(_strptime_datetime_date)
+        STRUCT_FOR_ID(_strptime_datetime_datetime)
+        STRUCT_FOR_ID(_strptime_datetime_time)
         STRUCT_FOR_ID(_swappedbytes_)
         STRUCT_FOR_ID(_type_)
         STRUCT_FOR_ID(_uninitialized_submodules)

Lib/_pydatetime.py

@@ -908,6 +908,7 @@ class date:
     fromtimestamp()
     today()
     fromordinal()
+    strptime()
 
     Operators:
 
@@ -1008,6 +1009,12 @@ def fromisocalendar(cls, year, week, day):
         This is the inverse of the date.isocalendar() function"""
         return cls(*_isoweek_to_gregorian(year, week, day))
 
+    @classmethod
+    def strptime(cls, date_string, format):
+        'string, format -> new date parsed from a string (like time.strptime()).'
+        import _strptime
+        return _strptime._strptime_datetime_date(cls, date_string, format)
+
     # Conversions to string
 
     def __repr__(self):
@@ -1328,6 +1335,7 @@ class time:
     Constructors:
 
     __new__()
+    strptime()
 
     Operators:
 
@@ -1386,6 +1394,12 @@ def __new__(cls, hour=0, minute=0, second=0, microsecond=0, tzinfo=None, *, fold
         self._fold = fold
         return self
 
+    @classmethod
+    def strptime(cls, date_string, format):
+        'string, format -> new time parsed from a string (like time.strptime()).'
+        import _strptime
+        return _strptime._strptime_datetime_time(cls, date_string, format)
+
     # Read-only field accessors
     @property
     def hour(self):
@@ -2092,7 +2106,7 @@ def __str__(self):
     def strptime(cls, date_string, format):
         'string, format -> new datetime parsed from a string (like time.strptime()).'
         import _strptime
-        return _strptime._strptime_datetime(cls, date_string, format)
+        return _strptime._strptime_datetime_datetime(cls, date_string, format)
 
     def utcoffset(self):
         """Return the timezone offset as timedelta positive east of UTC (negative west of

Lib/_strptime.py

@@ -567,8 +567,31 @@ def _strptime_time(data_string, format="%a %b %d %H:%M:%S %Y"):
     tt = _strptime(data_string, format)[0]
     return time.struct_time(tt[:time._STRUCT_TM_ITEMS])
 
-def _strptime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y"):
-    """Return a class cls instance based on the input string and the
+def _strptime_datetime_date(cls, data_string, format="%a %b %d %Y"):
+    """Return a date instance based on the input string and the
+    format string."""
+    tt, _, _ = _strptime(data_string, format)
+    args = tt[:3]
+    return cls(*args)
+
+def _strptime_datetime_time(cls, data_string, format="%H:%M:%S"):
+    """Return a time instance based on the input string and the
+    format string."""
+    tt, fraction, gmtoff_fraction = _strptime(data_string, format)
+    tzname, gmtoff = tt[-2:]
+    args = tt[3:6] + (fraction,)
+    if gmtoff is not None:
+        tzdelta = datetime_timedelta(seconds=gmtoff, microseconds=gmtoff_fraction)
+        if tzname:
+            tz = datetime_timezone(tzdelta, tzname)
+        else:
+            tz = datetime_timezone(tzdelta)
+        args += (tz,)
+
+    return cls(*args)
+
+def _strptime_datetime_datetime(cls, data_string, format="%a %b %d %H:%M:%S %Y"):
+    """Return a datetime instance based on the input string and the
     format string."""
     tt, fraction, gmtoff_fraction = _strptime(data_string, format)
     tzname, gmtoff = tt[-2:]

Lib/test/datetimetester.py

@@ -1109,6 +1109,65 @@ def test_delta_non_days_ignored(self):
         dt2 = dt - delta
         self.assertEqual(dt2, dt - days)
 
+    def test_strptime(self):
+        string = '2004-12-01'
+        format = '%Y-%m-%d'
+        expected = _strptime._strptime_datetime_date(date, string, format)
+        got = date.strptime(string, format)
+        self.assertEqual(expected, got)
+        self.assertIs(type(expected), date)
+        self.assertIs(type(got), date)
+
+        # bpo-34482: Check that surrogates are handled properly.
+        inputs = [
+            ('2004-12\ud80001', '%Y-%m\ud800%d'),
+            ('2004\ud80012-01', '%Y\ud800%m-%d'),
+        ]
+        for string, format in inputs:
+            with self.subTest(string=string, format=format):
+                expected = _strptime._strptime_datetime_date(date, string,
+                                                             format)
+                got = date.strptime(string, format)
+                self.assertEqual(expected, got)
+
+    def test_strptime_single_digit(self):
+        # bpo-34903: Check that single digit dates are allowed.
+        strptime = date.strptime
+        with self.assertRaises(ValueError):
+            # %y does require two digits.
+            newdate = strptime('01/02/3', '%d/%m/%y')
+
+        d1 = date(2003, 2, 1)
+        d2 = date(2003, 1, 2)
+        d3 = date(2003, 1, 25)
+        inputs = [
+            ('%d', '1/02/03',  '%d/%m/%y', d1),
+            ('%m', '01/2/03',  '%d/%m/%y', d1),
+            ('%j', '2/03',     '%j/%y',    d2),
+            ('%w', '6/04/03',  '%w/%U/%y', d1),
+            # %u requires a single digit.
+            ('%W', '6/4/2003', '%u/%W/%Y', d1),
+            ('%V', '6/4/2003', '%u/%V/%G', d3),
+        ]
+        for reason, string, format, target in inputs:
+            reason = 'test single digit ' + reason
+            with self.subTest(reason=reason,
+                              string=string,
+                              format=format,
+                              target=target):
+                newdate = strptime(string, format)
+                self.assertEqual(newdate, target, msg=reason)
+
+    @warnings_helper.ignore_warnings(category=DeprecationWarning)
+    def test_strptime_leap_year(self):
+        # GH-70647: warns if parsing a format with a day and no year.
+        with self.assertRaises(ValueError):
+            # The existing behavior that GH-70647 seeks to change.
+            date.strptime('02-29', '%m-%d')
+        with self._assertNotWarns(DeprecationWarning):
+            date.strptime('20-03-14', '%y-%m-%d')
+            date.strptime('02-29,2024', '%m-%d,%Y')
+
 class SubclassDate(date):
     sub_var = 1
 
@@ -2718,7 +2777,8 @@ def test_utcnow(self):
     def test_strptime(self):
         string = '2004-12-01 13:02:47.197'
         format = '%Y-%m-%d %H:%M:%S.%f'
-        expected = _strptime._strptime_datetime(self.theclass, string, format)
+        expected = _strptime._strptime_datetime_datetime(self.theclass, string,
+                                                         format)
         got = self.theclass.strptime(string, format)
         self.assertEqual(expected, got)
         self.assertIs(type(expected), self.theclass)
@@ -2732,8 +2792,8 @@ def test_strptime(self):
         ]
         for string, format in inputs:
             with self.subTest(string=string, format=format):
-                expected = _strptime._strptime_datetime(self.theclass, string,
-                                                        format)
+                expected = _strptime._strptime_datetime_datetime(self.theclass,
+                                                                 string, format)
                 got = self.theclass.strptime(string, format)
                 self.assertEqual(expected, got)
 
@@ -3726,6 +3786,83 @@ def test_compat_unpickle(self):
                     derived = loads(data, encoding='latin1')
                     self.assertEqual(derived, expected)
 
+    def test_strptime(self):
+        string = '13:02:47.197'
+        format = '%H:%M:%S.%f'
+        expected = _strptime._strptime_datetime_time(self.theclass, string,
+                                                     format)
+        got = self.theclass.strptime(string, format)
+        self.assertEqual(expected, got)
+        self.assertIs(type(expected), self.theclass)
+        self.assertIs(type(got), self.theclass)
+
+        # bpo-34482: Check that surrogates are handled properly.
+        inputs = [
+            ('13:02\ud80047.197', '%H:%M\ud800%S.%f'),
+            ('13\ud80002:47.197', '%H\ud800%M:%S.%f'),
+        ]
+        for string, format in inputs:
+            with self.subTest(string=string, format=format):
+                expected = _strptime._strptime_datetime_time(self.theclass,
+                                                             string, format)
+                got = self.theclass.strptime(string, format)
+                self.assertEqual(expected, got)
+
+        strptime = self.theclass.strptime
+        self.assertEqual(strptime("+0002", "%z").utcoffset(), 2 * MINUTE)
+        self.assertEqual(strptime("-0002", "%z").utcoffset(), -2 * MINUTE)
+        self.assertEqual(
+            strptime("-00:02:01.000003", "%z").utcoffset(),
+            -timedelta(minutes=2, seconds=1, microseconds=3)
+        )
+        # Only local timezone and UTC are supported
+        for tzseconds, tzname in ((0, 'UTC'), (0, 'GMT'),
+                                 (-_time.timezone, _time.tzname[0])):
+            if tzseconds < 0:
+                sign = '-'
+                seconds = -tzseconds
+            else:
+                sign ='+'
+                seconds = tzseconds
+            hours, minutes = divmod(seconds//60, 60)
+            tstr = "{}{:02d}{:02d} {}".format(sign, hours, minutes, tzname)
+            t = strptime(tstr, "%z %Z")
+            self.assertEqual(t.utcoffset(), timedelta(seconds=tzseconds))
+            self.assertEqual(t.tzname(), tzname)
+
+        # Can produce inconsistent time
+        tstr, fmt = "+1234 UTC", "%z %Z"
+        t = strptime(tstr, fmt)
+        self.assertEqual(t.utcoffset(), 12 * HOUR + 34 * MINUTE)
+        self.assertEqual(t.tzname(), 'UTC')
+        # yet will roundtrip
+        self.assertEqual(t.strftime(fmt), tstr)
+
+        # Produce naive time if no %z is provided
+        self.assertEqual(strptime("UTC", "%Z").tzinfo, None)
+
+        with self.assertRaises(ValueError): strptime("-2400", "%z")
+        with self.assertRaises(ValueError): strptime("-000", "%z")
+        with self.assertRaises(ValueError): strptime("z", "%z")
+
+    def test_strptime_single_digit(self):
+        # bpo-34903: Check that single digit times are allowed.
+        t = self.theclass(4, 5, 6)
+        inputs = [
+            ('%H', '4:05:06',   '%H:%M:%S',   t),
+            ('%M', '04:5:06',   '%H:%M:%S',   t),
+            ('%S', '04:05:6',   '%H:%M:%S',   t),
+            ('%I', '4am:05:06', '%I%p:%M:%S', t),
+        ]
+        for reason, string, format, target in inputs:
+            reason = 'test single digit ' + reason
+            with self.subTest(reason=reason,
+                              string=string,
+                              format=format,
+                              target=target):
+                newdate = self.theclass.strptime(string, format)
+                self.assertEqual(newdate, target, msg=reason)
+
     def test_bool(self):
         # time is always True.
         cls = self.theclass