gh-109798: Normalize _datetime and datetime error messages

Lib/_pydatetime.py

@@ -60,14 +60,14 @@ def _days_in_month(year, month):
 
 def _days_before_month(year, month):
     "year, month -> number of days in year preceding first day of month."
-    assert 1 <= month <= 12, 'month must be in 1..12'
+    assert 1 <= month <= 12, f"month must be in 1..12, not {month}"
     return _DAYS_BEFORE_MONTH[month] + (month > 2 and _is_leap(year))
 
 def _ymd2ord(year, month, day):
     "year, month, day -> ordinal, considering 01-Jan-0001 as day 1."
-    assert 1 <= month <= 12, 'month must be in 1..12'
+    assert 1 <= month <= 12, f"month must be in 1..12, not {month}"
     dim = _days_in_month(year, month)
-    assert 1 <= day <= dim, ('day must be in 1..%d' % dim)
+    assert 1 <= day <= dim, f"day must be in 1..{dim}, not {day}"
     return (_days_before_year(year) +
             _days_before_month(year, month) +
             day)
@@ -512,7 +512,7 @@ def _parse_isoformat_time(tstr):
 def _isoweek_to_gregorian(year, week, day):
     # Year is bounded this way because 9999-12-31 is (9999, 52, 5)
     if not MINYEAR <= year <= MAXYEAR:
-        raise ValueError(f"Year is out of range: {year}")
+        raise ValueError(f"year must be in {MINYEAR}..{MAXYEAR}, not {year}")
 
     if not 0 < week < 53:
         out_of_range = True
@@ -545,7 +545,7 @@ def _isoweek_to_gregorian(year, week, day):
 def _check_tzname(name):
     if name is not None and not isinstance(name, str):
         raise TypeError("tzinfo.tzname() must return None or string, "
-                        "not '%s'" % type(name))
+                        f"not {type(name).__name__!r}")
 
 # name is the offset-producing method, "utcoffset" or "dst".
 # offset is what it returned.
@@ -558,24 +558,24 @@ def _check_utc_offset(name, offset):
     if offset is None:
         return
     if not isinstance(offset, timedelta):
-        raise TypeError("tzinfo.%s() must return None "
-                        "or timedelta, not '%s'" % (name, type(offset)))
+        raise TypeError(f"tzinfo.{name}() must return None "
+                        f"or timedelta, not {type(offset).__name__!r}")
     if not -timedelta(1) < offset < timedelta(1):
-        raise ValueError("%s()=%s, must be strictly between "
-                         "-timedelta(hours=24) and timedelta(hours=24)" %
-                         (name, offset))
+        raise ValueError("offset must be a timedelta "
+                         "strictly between -timedelta(hours=24) and "
+                         f"timedelta(hours=24), not {offset!r}")
 
 def _check_date_fields(year, month, day):
     year = _index(year)
     month = _index(month)
     day = _index(day)
     if not MINYEAR <= year <= MAXYEAR:
-        raise ValueError('year must be in %d..%d' % (MINYEAR, MAXYEAR), year)
+        raise ValueError(f"year must be in {MINYEAR}..{MAXYEAR}, not {year}")
     if not 1 <= month <= 12:
-        raise ValueError('month must be in 1..12', month)
+        raise ValueError(f"month must be in 1..12, not {month}")
     dim = _days_in_month(year, month)
     if not 1 <= day <= dim:
-        raise ValueError('day must be in 1..%d' % dim, day)
+        raise ValueError(f"day must be in 1..{dim}, not {day}")
     return year, month, day
 
 def _check_time_fields(hour, minute, second, microsecond, fold):
@@ -584,20 +584,23 @@ def _check_time_fields(hour, minute, second, microsecond, fold):
     second = _index(second)
     microsecond = _index(microsecond)
     if not 0 <= hour <= 23:
-        raise ValueError('hour must be in 0..23', hour)
+        raise ValueError(f"hour must be in 0..23, not {hour}")
     if not 0 <= minute <= 59:
-        raise ValueError('minute must be in 0..59', minute)
+        raise ValueError(f"minute must be in 0..59, not {minute}")
     if not 0 <= second <= 59:
-        raise ValueError('second must be in 0..59', second)
+        raise ValueError(f"second must be in 0..59, not {second}")
     if not 0 <= microsecond <= 999999:
-        raise ValueError('microsecond must be in 0..999999', microsecond)
+        raise ValueError(f"microsecond must be in 0..999999, not {microsecond}")
     if fold not in (0, 1):
-        raise ValueError('fold must be either 0 or 1', fold)
+        raise ValueError(f"fold must be either 0 or 1, not {fold}")
     return hour, minute, second, microsecond, fold
 
 def _check_tzinfo_arg(tz):
     if tz is not None and not isinstance(tz, tzinfo):
-        raise TypeError("tzinfo argument must be None or of a tzinfo subclass")
+        raise TypeError(
+            "tzinfo argument must be None or of a tzinfo subclass, "
+            f"not {type(tz).__name__!r}"
+        )
 
 def _divide_and_round(a, b):
     """divide a by b and round result to the nearest integer
@@ -2418,7 +2421,7 @@ def __new__(cls, offset, name=_Omitted):
         if not cls._minoffset <= offset <= cls._maxoffset:
             raise ValueError("offset must be a timedelta "
                              "strictly between -timedelta(hours=24) and "
-                             "timedelta(hours=24).")
+                             f"timedelta(hours=24), not {offset!r}")
         return cls._create(offset, name)
 
     def __init_subclass__(cls):

Lib/test/datetimetester.py

@@ -1962,6 +1962,23 @@ def test_backdoor_resistance(self):
             # blow up because other fields are insane.
             self.theclass(base[:2] + bytes([ord_byte]) + base[3:])
 
+    def test_valuerror_messages(self):
+        pattern = re.compile(
+            r"(year|month|day) must be in \d+\.\.\d+, not \d+"
+        )
+        test_cases = [
+            (2009, 1, 32),      # Day out of range
+            (2009, 2, 31),      # Day out of range
+            (2009, 13, 1),      # Month out of range
+            (2009, 0, 1),       # Month out of range
+            (10000, 12, 31),    # Year out of range
+            (0, 12, 31),        # Year out of range
+        ]
+        for case in test_cases:
+            with self.subTest(case):
+                with self.assertRaisesRegex(ValueError, pattern):
+                    self.theclass(*case)
+
     def test_fromisoformat(self):
         # Test that isoformat() is reversible
         base_dates = [
@@ -3212,6 +3229,24 @@ class DateTimeSubclass(self.theclass):
                 self.assertEqual(res.year, 2013)
                 self.assertEqual(res.fold, fold)
 
+    def test_valuerror_messages(self):
+        pattern = re.compile(
+            r"(year|month|day|hour|minute|second) must "
+            r"be in \d+\.\.\d+, not \d+"
+        )
+        test_cases = [
+            (2009, 4, 1, 12, 30, 90),   # Second out of range
+            (2009, 4, 1, 12, 90, 45),   # Minute out of range
+            (2009, 4, 1, 25, 30, 45),   # Hour out of range
+            (2009, 4, 32, 24, 0, 0),    # Day out of range
+            (2009, 13, 1, 24, 0, 0),    # Month out of range
+            (9999, 12, 31, 24, 0, 0),   # Year out of range
+        ]
+        for case in test_cases:
+            with self.subTest(case):
+                with self.assertRaisesRegex(ValueError, pattern):
+                    self.theclass(*case)
+
     def test_fromisoformat_datetime(self):
         # Test that isoformat() is reversible
         base_dates = [
@@ -3505,6 +3540,25 @@ def test_fromisoformat_fails_datetime(self):
                 with self.assertRaises(ValueError):
                     self.theclass.fromisoformat(bad_str)
 
+    def test_fromisoformat_fails_datetime_valueerror(self):
+        pattern = re.compile(
+            r"(year|month|day|hour|minute|second) must "
+            r"be in \d+\.\.\d+, not \d+"
+        )
+        bad_strs = [
+            "2009-04-01T12:30:90",          # Second out of range
+            "2009-04-01T12:90:45",          # Minute out of range
+            "2009-04-01T25:30:45",          # Hour out of range
+            "2009-04-32T24:00:00",          # Day out of range
+            "2009-13-01T24:00:00",          # Month out of range
+            "9999-12-31T24:00:00",          # Year out of range
+        ]
+
+        for bad_str in bad_strs:
+            with self.subTest(bad_str=bad_str):
+                with self.assertRaisesRegex(ValueError, pattern):
+                    self.theclass.fromisoformat(bad_str)
+
     def test_fromisoformat_fails_surrogate(self):
         # Test that when fromisoformat() fails with a surrogate character as
         # the separator, the error message contains the original string
@@ -4481,6 +4535,21 @@ def utcoffset(self, t):
         t2 = t2.replace(tzinfo=Varies())
         self.assertTrue(t1 < t2)  # t1's offset counter still going up
 
+    def test_valuerror_messages(self):
+        pattern = re.compile(
+            r"(hour|minute|second|microsecond) must be in \d+\.\.\d+, not \d+"
+        )
+        test_cases = [
+            (12, 30, 90, 9999991),  # Microsecond out of range
+            (12, 30, 90, 000000),   # Second out of range
+            (25, 30, 45, 000000),   # Hour out of range
+            (12, 90, 45, 000000),   # Minute out of range
+        ]
+        for case in test_cases:
+            with self.subTest(case):
+                with self.assertRaisesRegex(ValueError, pattern):
+                    self.theclass(*case)
+
     def test_fromisoformat(self):
         time_examples = [
             (0, 0, 0, 0),

Misc/NEWS.d/next/Library/2024-11-27-23-29-05.gh-issue-109798.OPj1CT.rst

@@ -0,0 +1 @@
+Added additional information into error messages in :mod:`datetime`, and made the messages more consistent between the C and Python implementations. Patch by Semyon Moroz.

Modules/_datetimemodule.c

@@ -637,17 +637,19 @@ check_date_args(int year, int month, int day)
 {
 
     if (year < MINYEAR || year > MAXYEAR) {
-        PyErr_Format(PyExc_ValueError, "year %i is out of range", year);
+        PyErr_Format(PyExc_ValueError,
+                     "year must be in %d..%d, not %d", MINYEAR, MAXYEAR, year);
         return -1;
     }
     if (month < 1 || month > 12) {
-        PyErr_SetString(PyExc_ValueError,
-                        "month must be in 1..12");
+        PyErr_Format(PyExc_ValueError,
+                     "month must be in 1..12, not %d", month);
         return -1;
     }
-    if (day < 1 || day > days_in_month(year, month)) {
-        PyErr_SetString(PyExc_ValueError,
-                        "day is out of range for month");
+    int dim = days_in_month(year, month);
+    if (day < 1 || day > dim) {
+        PyErr_Format(PyExc_ValueError,
+                     "day must be in 1..%d, not %d", dim, day);
         return -1;
     }
     return 0;
@@ -660,28 +662,25 @@ static int
 check_time_args(int h, int m, int s, int us, int fold)
 {
     if (h < 0 || h > 23) {
-        PyErr_SetString(PyExc_ValueError,
-                        "hour must be in 0..23");
+        PyErr_Format(PyExc_ValueError, "hour must be in 0..23, not %i", h);
         return -1;
     }
     if (m < 0 || m > 59) {
-        PyErr_SetString(PyExc_ValueError,
-                        "minute must be in 0..59");
+        PyErr_Format(PyExc_ValueError, "minute must be in 0..59, not %i", m);
         return -1;
     }
     if (s < 0 || s > 59) {
-        PyErr_SetString(PyExc_ValueError,
-                        "second must be in 0..59");
+        PyErr_Format(PyExc_ValueError, "second must be in 0..59, not %i", s);
         return -1;
     }
     if (us < 0 || us > 999999) {
-        PyErr_SetString(PyExc_ValueError,
-                        "microsecond must be in 0..999999");
+        PyErr_Format(PyExc_ValueError,
+                     "microsecond must be in 0..999999, not %i", us);
         return -1;
     }
     if (fold != 0 && fold != 1) {
-        PyErr_SetString(PyExc_ValueError,
-                        "fold must be either 0 or 1");
+        PyErr_Format(PyExc_ValueError,
+                     "fold must be either 0 or 1, not %i", fold);
         return -1;
     }
     return 0;
@@ -1435,8 +1434,7 @@ new_timezone(PyObject *offset, PyObject *name)
         GET_TD_DAYS(offset) < -1 || GET_TD_DAYS(offset) >= 1) {
         PyErr_Format(PyExc_ValueError, "offset must be a timedelta"
                      " strictly between -timedelta(hours=24) and"
-                     " timedelta(hours=24),"
-                     " not %R.", offset);
+                     " timedelta(hours=24), not %R", offset);
         return NULL;
     }
 
@@ -1505,10 +1503,10 @@ call_tzinfo_method(PyObject *tzinfo, const char *name, PyObject *tzinfoarg)
                 GET_TD_SECONDS(offset) == 0 &&
                 GET_TD_MICROSECONDS(offset) < 1) ||
             GET_TD_DAYS(offset) < -1 || GET_TD_DAYS(offset) >= 1) {
-            Py_DECREF(offset);
             PyErr_Format(PyExc_ValueError, "offset must be a timedelta"
                          " strictly between -timedelta(hours=24) and"
-                         " timedelta(hours=24).");
+                         " timedelta(hours=24), not %R", offset);
+            Py_DECREF(offset);
             return NULL;
         }
     }
@@ -2261,7 +2259,7 @@ get_float_as_integer_ratio(PyObject *floatobj)
     if (!PyTuple_Check(ratio)) {
         PyErr_Format(PyExc_TypeError,
                      "unexpected return type from as_integer_ratio(): "
-                     "expected tuple, got '%.200s'",
+                     "expected tuple, not '%.200s'",
                      Py_TYPE(ratio)->tp_name);
         Py_DECREF(ratio);
         return NULL;
@@ -3382,7 +3380,8 @@ date_fromisocalendar(PyObject *cls, PyObject *args, PyObject *kw)
     int rv = iso_to_ymd(year, week, day, &year, &month, &day);
 
     if (rv == -4) {
-        PyErr_Format(PyExc_ValueError, "Year is out of range: %d", year);
+        PyErr_Format(PyExc_ValueError,
+                     "year must be in %d..%d, not %d", MINYEAR, MAXYEAR, year);
         return NULL;
     }
 
@@ -3392,7 +3391,7 @@ date_fromisocalendar(PyObject *cls, PyObject *args, PyObject *kw)
     }
 
     if (rv == -3) {
-        PyErr_Format(PyExc_ValueError, "Invalid day: %d (range is [1, 7])",
+        PyErr_Format(PyExc_ValueError, "Invalid weekday: %d (range is [1, 7])",
                      day);
         return NULL;
     }
@@ -4378,8 +4377,7 @@ timezone_fromutc(PyDateTime_TimeZone *self, PyDateTime_DateTime *dt)
         return NULL;
     }
     if (!HASTZINFO(dt) || dt->tzinfo != (PyObject *)self) {
-        PyErr_SetString(PyExc_ValueError, "fromutc: dt.tzinfo "
-                        "is not self");
+        PyErr_SetString(PyExc_ValueError, "fromutc: dt.tzinfo is not self");
         return NULL;
     }
 
@@ -5352,7 +5350,8 @@ utc_to_seconds(int year, int month, int day,
 
     /* ymd_to_ord() doesn't support year <= 0 */
     if (year < MINYEAR || year > MAXYEAR) {
-        PyErr_Format(PyExc_ValueError, "year %i is out of range", year);
+        PyErr_Format(PyExc_ValueError,
+                     "year must be in %d..%d, not %d", MINYEAR, MAXYEAR, year);
         return -1;
     }