BUG: Catch overflow in both directions for checked add

asv_bench/benchmarks/algorithms.py

@@ -15,6 +15,14 @@ def setup(self):
         self.int = pd.Int64Index(np.arange(N).repeat(5))
         self.float = pd.Float64Index(np.random.randn(N).repeat(5))
 
+        # Convenience naming.
+        self.checked_add = pd.core.nanops._checked_add_with_arr
+
+        self.arr = np.arange(1000000)
+        self.arrpos = np.arange(1000000)
+        self.arrneg = np.arange(-1000000, 0)
+        self.arrmixed = np.array([1, -1]).repeat(500000)
+
     def time_int_factorize(self):
         self.int.factorize()
 
@@ -29,3 +37,21 @@ def time_int_duplicated(self):
 
     def time_float_duplicated(self):
         self.float.duplicated()
+
+    def time_add_overflow_pos_scalar(self):
+        self.checked_add(self.arr, 1)
+
+    def time_add_overflow_neg_scalar(self):
+        self.checked_add(self.arr, -1)
+
+    def time_add_overflow_zero_scalar(self):
+        self.checked_add(self.arr, 0)
+
+    def time_add_overflow_pos_arr(self):
+        self.checked_add(self.arr, self.arrpos)
+
+    def time_add_overflow_neg_arr(self):
+        self.checked_add(self.arr, self.arrneg)
+
+    def time_add_overflow_mixed_arr(self):
+        self.checked_add(self.arr, self.arrmixed)

asv_bench/benchmarks/timedelta.py

@@ -1,5 +1,5 @@
 from .pandas_vb_common import *
-from pandas import to_timedelta
+from pandas import to_timedelta, Timestamp
 
 
 class timedelta_convert_int(object):
@@ -47,3 +47,14 @@ def time_timedelta_convert_coerce(self):
 
     def time_timedelta_convert_ignore(self):
         to_timedelta(self.arr, errors='ignore')
+
+
+class timedelta_add_overflow(object):
+    goal_time = 0.2
+
+    def setup(self):
+        self.td = to_timedelta(np.arange(1000000))
+        self.ts = Timestamp('2000')
+
+    def test_add_td_ts(self):
+        self.td + self.ts

doc/source/whatsnew/v0.19.1.txt

@@ -35,6 +35,7 @@ Bug Fixes
 
 
 - Bug in localizing an ambiguous timezone when a boolean is passed (:issue:`14402`)
+- Bug in ``TimedeltaIndex`` addition with a Datetime-like object where addition overflow in the negative direction was not being caught (:issue:`14068`, :issue:`14453`)
 
 
 

pandas/core/nanops.py

@@ -11,6 +11,7 @@
 
 import pandas.hashtable as _hash
 from pandas import compat, lib, algos, tslib
+from pandas.compat.numpy import _np_version_under1p10
 from pandas.types.common import (_ensure_int64, _ensure_object,
                                  _ensure_float64, _get_dtype,
                                  is_float, is_scalar,
@@ -829,9 +830,37 @@ def _checked_add_with_arr(arr, b):
 
     Raises
     ------
-    OverflowError if any x + y exceeds the maximum int64 value.
+    OverflowError if any x + y exceeds the maximum or minimum int64 value.
     """
-    if (np.iinfo(np.int64).max - b < arr).any():
-        raise OverflowError("Python int too large to "
-                            "convert to C long")
+    # For performance reasons, we broadcast 'b' to the new array 'b2'
+    # so that it has the same size as 'arr'.
+    if _np_version_under1p10:
+        if lib.isscalar(b):
+            b2 = np.empty(arr.shape)
+            b2.fill(b)
+        else:
+            b2 = b
+    else:
+        b2 = np.broadcast_to(b, arr.shape)
+
+    # gh-14324: For each element in 'arr' and its corresponding element
+    # in 'b2', we check the sign of the element in 'b2'. If it is positive,
+    # we then check whether its sum with the element in 'arr' exceeds
+    # np.iinfo(np.int64).max. If so, we have an overflow error. If it
+    # it is negative, we then check whether its sum with the element in
+    # 'arr' exceeds np.iinfo(np.int64).min. If so, we have an overflow
+    # error as well.
+    mask1 = b2 > 0
+    mask2 = b2 < 0
+
+    if not mask1.any():
+        to_raise = (np.iinfo(np.int64).min - b2 > arr).any()
+    elif not mask2.any():
+        to_raise = (np.iinfo(np.int64).max - b2 < arr).any()
+    else:
+        to_raise = ((np.iinfo(np.int64).max - b2[mask1] < arr[mask1]).any() or
+                    (np.iinfo(np.int64).min - b2[mask2] > arr[mask2]).any())
+
+    if to_raise:
+        raise OverflowError("Overflow in int64 addition")
     return arr + b

pandas/tests/test_nanops.py

@@ -1004,13 +1004,20 @@ def prng(self):
 
 def test_int64_add_overflow():
     # see gh-14068
-    msg = "too (big|large) to convert"
+    msg = "Overflow in int64 addition"
     m = np.iinfo(np.int64).max
+    n = np.iinfo(np.int64).min
 
     with tm.assertRaisesRegexp(OverflowError, msg):
         nanops._checked_add_with_arr(np.array([m, m]), m)
     with tm.assertRaisesRegexp(OverflowError, msg):
         nanops._checked_add_with_arr(np.array([m, m]), np.array([m, m]))
+    with tm.assertRaisesRegexp(OverflowError, msg):
+        nanops._checked_add_with_arr(np.array([n, n]), n)
+    with tm.assertRaisesRegexp(OverflowError, msg):
+        nanops._checked_add_with_arr(np.array([n, n]), np.array([n, n]))
+    with tm.assertRaisesRegexp(OverflowError, msg):
+        nanops._checked_add_with_arr(np.array([m, n]), np.array([n, n]))
     with tm.assertRaisesRegexp(OverflowError, msg):
         with tm.assert_produces_warning(RuntimeWarning):
             nanops._checked_add_with_arr(np.array([m, m]),

pandas/tseries/tests/test_timedeltas.py

@@ -1957,6 +1957,8 @@ def test_add_overflow(self):
             to_timedelta(106580, 'D') + Timestamp('2000')
         with tm.assertRaisesRegexp(OverflowError, msg):
             Timestamp('2000') + to_timedelta(106580, 'D')
+
+        msg = "Overflow in int64 addition"
         with tm.assertRaisesRegexp(OverflowError, msg):
             to_timedelta([106580], 'D') + Timestamp('2000')
         with tm.assertRaisesRegexp(OverflowError, msg):