MAINT: A few updates to the array_api

numpy/array_api/_array_object.py

@@ -244,6 +244,9 @@ def _validate_index(key, shape):
         The following cases are allowed by NumPy, but not specified by the array
         API specification:
 
+        - Multidimensional (tuple) indices must include an index for every
+          axis of the array unless an ellipsis is included.
+
         - The start and stop of a slice may not be out of bounds. In
           particular, for a slice ``i:j:k`` on an axis of size ``n``, only the
           following are allowed:
@@ -322,6 +325,10 @@ def _validate_index(key, shape):
                 zip(key[:ellipsis_i:-1], shape[:ellipsis_i:-1])
             ):
                 Array._validate_index(idx, (size,))
+            if n_ellipsis == 0 and len(key) < len(shape):
+                raise IndexError(
+                    "Multidimensional indices must either index every axis of the array or use an ellipsis"
+                )
             return key
         elif isinstance(key, bool):
             return key

numpy/array_api/_creation_functions.py

@@ -60,7 +60,9 @@ def asarray(
     if copy is False:
         # Note: copy=False is not yet implemented in np.asarray
         raise NotImplementedError("copy=False is not yet implemented")
-    if isinstance(obj, Array) and (dtype is None or obj.dtype == dtype):
+    if isinstance(obj, Array):
+        if dtype is not None and obj.dtype != dtype:
+            copy = True
         if copy is True:
             return Array._new(np.array(obj._array, copy=True, dtype=dtype))
         return obj

numpy/array_api/tests/test_array_object.py

@@ -74,6 +74,9 @@ def test_validate_index():
     assert_raises(IndexError, lambda: a[None, ...])
     assert_raises(IndexError, lambda: a[..., None])
 
+    # Multiaxis indices must contain exactly as many indices as dimensions
+    assert_raises(IndexError, lambda: a[()])
+    assert_raises(IndexError, lambda: a[0,])
 
 def test_operators():
     # For every operator, we test that it works for the required type