MAINT: dtype.name works for NEP 42 dtypes

ngoldbaum · ngoldbaum · commit 61d82aa6c655 · 2023-01-19T14:17:14.000-07:00
diff --git a/numpy/core/_dtype.py b/numpy/core/_dtype.py
@@ -334,6 +334,8 @@ def _name_includes_bit_suffix(dtype):
     elif dtype.type == np.bool_:
         # implied
         return False
+    elif dtype.type is None:
+        return True
     elif np.issubdtype(dtype, np.flexible) and _isunsized(dtype):
         # unspecified
         return False
@@ -351,6 +353,8 @@ def _name_get(dtype):
     if issubclass(dtype.type, np.void):
         # historically, void subclasses preserve their name, eg `record64`
         name = dtype.type.__name__
+    elif dtype.kind == '\x00':
+        name = type(dtype).__name__
     else:
         name = _kind_name(dtype)
 
diff --git a/numpy/core/tests/test_custom_dtypes.py b/numpy/core/tests/test_custom_dtypes.py
@@ -45,6 +45,9 @@ def test_repr(self):
         # Check the repr, mainly to cover the code paths:
         assert repr(SF(scaling=1.)) == "_ScaledFloatTestDType(scaling=1.0)"
 
+    def test_dtype_name(self):
+        assert SF(1.).name == "_ScaledFloatTestDType64"
+
     @pytest.mark.parametrize("scaling", [1., -1., 2.])
     def test_sfloat_from_float(self, scaling):
         a = np.array([1., 2., 3.]).astype(dtype=SF(scaling))
