Closes #5413: bug in pd.array when dtype is ak.bigint

arkouda/numpy/pdarraycreation.py

@@ -331,7 +331,7 @@ def array(
         try:
             from arkouda.numpy.dtypes import dtype as ak_dtype
 
-            if dtype is not None and ak_dtype(dtype) != "bigint":
+            if dtype is not None and ak_dtype(dtype) not in (bigint, "bigint"):
                 # if the user specified dtype, use that dtype
                 a = np.array(a, dtype=dtype)
             elif (

arkouda/pandas/extension/_arkouda_array.py

@@ -22,7 +22,6 @@
     ArkoudaInt64Dtype,
     ArkoudaUint8Dtype,
     ArkoudaUint64Dtype,
-    _ArkoudaBaseDtype,
 )
 
 
@@ -114,6 +113,8 @@ def __init__(
     def _from_sequence(cls, scalars, dtype=None, copy=False):
         from arkouda.numpy.pdarraycreation import array as ak_array
 
+        from ._dtypes import ArkoudaBigintDtype
+
         # normalize dtype input
         if (
             dtype is not None
@@ -122,13 +123,10 @@ def _from_sequence(cls, scalars, dtype=None, copy=False):
                 or str(dtype) in {"bigint", "ak.bigint"}
             )
             or dtype is ArkoudaBigintDtype
+            or isinstance(dtype, ArkoudaBigintDtype)
         ):
             dtype = "bigint"
 
-        # If pandas passes our own EA dtype, ignore it and infer from data
-        if isinstance(dtype, _ArkoudaBaseDtype):
-            dtype = dtype.numpy_dtype
-
         if dtype is not None and hasattr(dtype, "numpy_dtype"):
             dtype = dtype.numpy_dtype
 

tests/pandas/extension/arkouda_array_extension.py

@@ -389,6 +389,16 @@ def test_copy_default_behaves_like_deep_true(self, ea):
         # Values preserved
         np.testing.assert_array_equal(default_copy.to_numpy(), ea.to_numpy())
 
+    def test_pd_array_construct_from_ak_bigint_pdarray_explicit_dtype_does_not_cast_to_object(self):
+        # Regression: used to try cast<bigint,object,1> and fail on server
+        a = ak.array(np.array([0, -1, 2]), dtype="bigint")
+
+        b = pd.array(a, dtype="ak.bigint")
+
+        # Should be Arkouda-backed and preserve values
+        assert str(b.dtype) in ("ak_bigint", "ak.bigint", "bigint")  # tolerate aliasing
+        np.testing.assert_array_equal(np.asarray(b), np.array([0, -1, 2], dtype=object))
+
 
 class TestArkoudaArrayAsType:
     def test_arkouda_array_astype_object_returns_numpy_object_array(self):