ENH: cupy: make isin accept int scalars

Author: ev-br

array_api_compat/cupy/_aliases.py

@@ -167,6 +167,15 @@ def searchsorted(
     return cp.searchsorted(x1, x2, side, sorter)
 
 
+# CuPy isin does not accept scalars
+def isin(x1: Array | int, x2: Array | int, /, *, invert: bool = False, **kwds) -> Array:
+    if isinstance(x1, int):
+        x1 = cp.asarray(x1)
+    if isinstance(x2, int):
+        x2 = cp.asarray(x2)
+    return cp.isin(x1, x2)
+
+
 # These functions are completely new here. If the library already has them
 # (i.e., numpy 2.0), use the library version instead of our wrapper.
 if hasattr(cp, 'vecdot'):
@@ -191,7 +200,7 @@ def searchsorted(
                               'bool', 'concat', 'count_nonzero', 'pow', 'sign',
                               'ceil', 'floor', 'trunc', 'take_along_axis',
                               'broadcast_arrays', 'meshgrid',
-                              'searchsorted',
+                              'searchsorted', 'isin',
 ]