Check complex numbers explicitly

Author: dcherian

src/zarr/core/metadata/v3.py

@@ -485,12 +485,20 @@ def parse_fill_value(
         pass
     elif fill_value in ["Infinity", "-Infinity"] and not np.isfinite(casted_value):
         pass
-    elif np_dtype.kind in "cf":
+    elif np_dtype.kind == "f":
         # float comparison is not exact, especially when dtype <float64
-        # so we us np.isclose for this comparison.
+        # so we use np.isclose for this comparison.
         # this also allows us to compare nan fill_values
         if not np.isclose(fill_value, casted_value, equal_nan=True):
             raise ValueError(f"fill value {fill_value!r} is not valid for dtype {data_type}")
+    elif np_dtype.kind == "c":
+        # confusingly np.isclose(np.inf, np.inf + 0j) is False, so compare real and imag parts
+        # explicitly.
+        if not (
+            np.isclose(np.real(fill_value), np.real(casted_value), equal_nan=True)
+            and np.isclose(np.imag(fill_value), np.imag(casted_value), equal_nan=True)
+        ):
+            raise ValueError(f"fill value {fill_value!r} is not valid for dtype {data_type}")
     else:
         if fill_value != casted_value:
             raise ValueError(f"fill value {fill_value!r} is not valid for dtype {data_type}")

tests/test_array.py

@@ -1,4 +1,5 @@
 import json
+import math
 import pickle
 from itertools import accumulate
 from typing import Any, Literal
@@ -448,7 +449,7 @@ def test_array_create_order(
         (np.inf, ["Infinity", 0.0]),
         (np.inf * 1j, ["NaN", "Infinity"]),
         (-np.inf, ["-Infinity", 0.0]),
-        # (math.inf, ["Infinity", 0.0]),
+        (math.inf, ["Infinity", 0.0]),
     ],
 )
 async def test_special_complex_fill_values_roundtrip(fill_value: Any, expected: list[Any]) -> None: