Merge pull request #11979 from hmaarrfk/block_single_array_copy_test

MAINT: Ensure that a copy of the array is returned when calling `block`.

1 files changed, 8 insertions, 1 deletions

diff --git a/numpy/core/shape_base.py b/numpy/core/shape_base.py
index 52717abda..feb1605bc 100644
--- a/numpy/core/shape_base.py
+++ b/numpy/core/shape_base.py
@@ -617,4 +617,11 @@ def block(arrays):
                 _block_format_index(bottom_index)
             )
         )
-    return _block(arrays, list_ndim, max(arr_ndim, list_ndim))
+    result = _block(arrays, list_ndim, max(arr_ndim, list_ndim))
+    if list_ndim == 0:
+        # Catch an edge case where _block returns a view because
+        # `arrays` is a single numpy array and not a list of numpy arrays.
+        # This might copy scalars or lists twice, but this isn't a likely
+        # usecase for those interested in performance
+        result = result.copy()
+    return result