Wrap numpy and cupy nonzero to error on zero-dimensional arrays

Author: asmeurer

array_api_compat/common/_aliases.py

@@ -386,6 +386,12 @@ def sort(
         res = xp.flip(res, axis=axis)
     return res
 
+# nonzero should error for zero-dimensional arrays
+def nonzero(x: ndarray, /, xp, **kwargs) -> Tuple[ndarray, ...]:
+    if x.ndim == 0:
+        raise ValueError("nonzero() does not support zero-dimensional arrays")
+    return xp.nonzero(x, **kwargs)
+
 # sum() and prod() should always upcast when dtype=None
 def sum(
     x: ndarray,
@@ -526,5 +532,5 @@ def isdtype(
            'UniqueAllResult', 'UniqueCountsResult', 'UniqueInverseResult',
            'unique_all', 'unique_counts', 'unique_inverse', 'unique_values',
            'astype', 'std', 'var', 'permute_dims', 'reshape', 'argsort',
-           'sort', 'sum', 'prod', 'ceil', 'floor', 'trunc', 'matmul',
-           'matrix_transpose', 'tensordot', 'vecdot', 'isdtype']
+           'sort', 'nonzero', 'sum', 'prod', 'ceil', 'floor', 'trunc',
+           'matmul', 'matrix_transpose', 'tensordot', 'vecdot', 'isdtype']

array_api_compat/cupy/_aliases.py

@@ -52,6 +52,7 @@
 reshape = get_xp(cp)(_aliases.reshape)
 argsort = get_xp(cp)(_aliases.argsort)
 sort = get_xp(cp)(_aliases.sort)
+nonzero = get_xp(cp)(_aliases.nonzero)
 sum = get_xp(cp)(_aliases.sum)
 prod = get_xp(cp)(_aliases.prod)
 ceil = get_xp(cp)(_aliases.ceil)

array_api_compat/numpy/_aliases.py

@@ -52,6 +52,7 @@
 reshape = get_xp(np)(_aliases.reshape)
 argsort = get_xp(np)(_aliases.argsort)
 sort = get_xp(np)(_aliases.sort)
+nonzero = get_xp(np)(_aliases.nonzero)
 sum = get_xp(np)(_aliases.sum)
 prod = get_xp(np)(_aliases.prod)
 ceil = get_xp(np)(_aliases.ceil)