Add inplace arithmetic operators to MaskedType (#11987)

Closes #11887

After merging, we will support syntax like `a += b` inside UDFs used through `DataFrame.apply` and `Series.apply`.

Authors:
  - https://github.com/brandon-b-miller

Approvers:
  - Bradley Dice (https://github.com/bdice)

URL: #11987

python/cudf/cudf/core/udf/_ops.py

@@ -11,6 +11,13 @@
     operator.floordiv,
     operator.mod,
     operator.pow,
+    operator.iadd,
+    operator.isub,
+    operator.imul,
+    operator.itruediv,
+    operator.floordiv,
+    operator.ipow,
+    operator.imod,
 ]
 
 bitwise_ops = [operator.and_, operator.or_, operator.xor]

python/cudf/cudf/tests/test_udf_masked_ops.py

@@ -197,6 +197,10 @@ def func(row):
         operator.pow,
         operator.truediv,
         operator.floordiv,
+        operator.imod,
+        operator.ipow,
+        operator.itruediv,
+        operator.ifloordiv,
     }:
         # The following tests cases yield undefined behavior:
         # - truediv(x, False) because its dividing by zero
@@ -219,7 +223,7 @@ def func(row):
     # Just a single column -> result will be all NA
     gdf = cudf.DataFrame({"data": data})
 
-    if constant == 1 and op is operator.pow:
+    if constant == 1 and op in {operator.pow, operator.ipow}:
         # The following tests cases yield differing results from pandas:
         # - 1**NA
         # - True**NA
@@ -237,7 +241,7 @@ def func(row):
 
     gdf = cudf.DataFrame({"data": data})
 
-    if 1 in gdf["data"] and op is operator.pow:
+    if 1 in gdf["data"] and op in {operator.pow, operator.ipow}:
         # In pandas, 1**NA == 1.
         pytest.skip()
     run_masked_udf_test(func, gdf, check_dtype=False)
@@ -483,7 +487,7 @@ def func(x):
 
     # Just a single column -> result will be all NA
     data = cudf.Series([1, 2, cudf.NA])
-    if constant is cudf.NA and op is operator.pow:
+    if constant is cudf.NA and op in {operator.pow, operator.ipow}:
         # in pandas, 1**NA == 1. In cudf, 1**NA == 1.
         with pytest.xfail():
             run_masked_udf_series(func, data, check_dtype=False)
@@ -499,7 +503,11 @@ def func(x):
 
     # Just a single column -> result will be all NA
     data = cudf.Series([1, 2, cudf.NA])
-    if constant is not cudf.NA and constant == 1 and op is operator.pow:
+    if (
+        constant is not cudf.NA
+        and constant == 1
+        and op in {operator.pow, operator.ipow}
+    ):
         # in pandas, 1**NA == 1. In cudf, 1**NA == 1.
         with pytest.xfail():
             run_masked_udf_series(func, data, check_dtype=False)