BUG: Assorted DTA/TDA/PI bugfixes (#24397)

doc/source/whatsnew/v0.24.0.rst

@@ -1321,6 +1321,7 @@ Datetimelike
 - Bug in :class:`DatetimeIndex` and :class:`TimedeltaIndex` where indexing with ``Ellipsis`` would incorrectly lose the index's ``freq`` attribute (:issue:`21282`)
 - Clarified error message produced when passing an incorrect ``freq`` argument to :class:`DatetimeIndex` with ``NaT`` as the first entry in the passed data (:issue:`11587`)
 - Bug in :func:`to_datetime` where ``box`` and ``utc`` arguments were ignored when passing a :class:`DataFrame` or ``dict`` of unit mappings (:issue:`23760`)
+- Bug in :class:`PeriodIndex` where comparisons against an array-like object with length 1 failed to raise ``ValueError`` (:issue:`23078`)
 
 Timedelta
 ^^^^^^^^^

pandas/core/arrays/datetimelike.py

@@ -1298,7 +1298,8 @@ def _ensure_datetimelike_to_i8(other, to_utc=False):
 
     if lib.is_scalar(other) and isna(other):
         return iNaT
-    elif isinstance(other, (PeriodArray, ABCIndexClass)):
+    elif isinstance(other, (PeriodArray, ABCIndexClass,
+                            DatetimeLikeArrayMixin)):
         # convert tz if needed
         if getattr(other, 'tz', None) is not None:
             if to_utc:

pandas/core/arrays/datetimes.py

@@ -97,6 +97,8 @@ def _dt_array_cmp(cls, op):
     def wrapper(self, other):
         meth = getattr(dtl.DatetimeLikeArrayMixin, opname)
 
+        other = lib.item_from_zerodim(other)
+
         if isinstance(other, (datetime, np.datetime64, compat.string_types)):
             if isinstance(other, (datetime, np.datetime64)):
                 # GH#18435 strings get a pass from tzawareness compat
@@ -111,8 +113,10 @@ def wrapper(self, other):
             result = op(self.asi8, other.view('i8'))
             if isna(other):
                 result.fill(nat_result)
-        elif lib.is_scalar(other):
+        elif lib.is_scalar(other) or np.ndim(other) == 0:
             return ops.invalid_comparison(self, other, op)
+        elif len(other) != len(self):
+            raise ValueError("Lengths must match")
         else:
             if isinstance(other, list):
                 try:

pandas/core/arrays/period.py

@@ -56,6 +56,9 @@ def wrapper(self, other):
         # return here with an unboxed PeriodArray). But before we do that,
         # we do a bit of validation on type (Period) and freq, so that our
         # error messages are sensible
+        if is_list_like(other) and len(other) != len(self):
+            raise ValueError("Lengths must match")
+
         not_implemented = isinstance(other, (ABCSeries, ABCIndexClass))
         if not_implemented:
             other = other._values

pandas/core/arrays/timedeltas.py

@@ -89,6 +89,9 @@ def wrapper(self, other):
         elif not is_list_like(other):
             return ops.invalid_comparison(self, other, op)
 
+        elif len(other) != len(self):
+            raise ValueError("Lengths must match")
+
         else:
             try:
                 other = type(self)._from_sequence(other)._data

pandas/core/indexes/base.py

@@ -5094,6 +5094,7 @@ def _evaluate_numeric_unary(self):
                 attrs = self._maybe_update_attributes(attrs)
                 return Index(op(self.values), **attrs)
 
+            _evaluate_numeric_unary.__name__ = opstr
             return _evaluate_numeric_unary
 
         cls.__neg__ = _make_evaluate_unary(operator.neg, '__neg__')

pandas/core/ops.py

@@ -1390,6 +1390,7 @@ def f(self, other):
 
             return self
 
+        f.__name__ = "__i{name}__".format(name=method.__name__.strip("__"))
         return f
 
     new_methods.update(
@@ -1574,6 +1575,7 @@ def wrapper(left, right):
         return construct_result(left, result,
                                 index=left.index, name=res_name, dtype=None)
 
+    wrapper.__name__ = op_name
     return wrapper
 
 
@@ -1762,6 +1764,7 @@ def wrapper(self, other, axis=None):
             return self._constructor(res_values, index=self.index,
                                      name=res_name, dtype='bool')
 
+    wrapper.__name__ = op_name
     return wrapper
 
 

pandas/core/series.py

@@ -91,6 +91,7 @@ def wrapper(self):
         raise TypeError("cannot convert the series to "
                         "{0}".format(str(converter)))
 
+    wrapper.__name__ = "__{name}__".format(name=converter.__name__)
     return wrapper
 
 # ----------------------------------------------------------------------

pandas/tests/arrays/test_datetimelike.py

@@ -59,6 +59,21 @@ def timedelta_index(request):
 class SharedTests(object):
     index_cls = None
 
+    def test_compare_len1_raises(self):
+        # make sure we raise when comparing with different lengths, specific
+        #  to the case where one has length-1, which numpy would broadcast
+        data = np.arange(10, dtype='i8')
+
+        idx = self.index_cls._simple_new(data, freq='D')
+        arr = self.array_cls(idx)
+
+        with pytest.raises(ValueError, match="Lengths must match"):
+            arr == arr[:1]
+
+        # test the index classes while we're at it, GH#23078
+        with pytest.raises(ValueError, match="Lengths must match"):
+            idx <= idx[[0]]
+
     def test_take(self):
         data = np.arange(100, dtype='i8')
         np.random.shuffle(data)
@@ -119,6 +134,15 @@ class TestDatetimeArray(SharedTests):
     index_cls = pd.DatetimeIndex
     array_cls = DatetimeArray
 
+    def test_round(self, tz_naive_fixture):
+        # GH#24064
+        tz = tz_naive_fixture
+        dti = pd.date_range('2016-01-01 01:01:00', periods=3, freq='H', tz=tz)
+
+        result = dti.round(freq='2T')
+        expected = dti - pd.Timedelta(minutes=1)
+        tm.assert_index_equal(result, expected)
+
     def test_array_object_dtype(self, tz_naive_fixture):
         # GH#23524
         tz = tz_naive_fixture