fix: allow zero strides on empty arrays (#1611)

Treat shapes with an empty axis as non-overlapping when validating
mutable views.

This allows zero strides on empty arrays while keeping the existing
overlap checks for non-empty shapes.

Fixes #1609

Author: Guflly

src/dimension/mod.rs

@@ -57,6 +57,10 @@ pub fn stride_offset(n: Ix, stride: Ix) -> isize
 /// possible offset along the preceding axes. (Axes of length ≤1 are ignored.)
 pub(crate) fn dim_stride_overlap<D: Dimension>(dim: &D, strides: &D) -> bool
 {
+    if dim.slice().contains(&0) {
+        return false;
+    }
+
     let order = strides._fastest_varying_stride_order();
     let mut sum_prev_offsets = 0;
     for &index in order.slice() {

tests/array.rs

@@ -2241,6 +2241,14 @@ fn test_view_from_shape_ptr()
     assert_eq!(view, aview2(&[[0, 0, 2], [3, 4, 6]]));
 }
 
+#[test]
+fn test_view_mut_from_shape_ptr_empty_zero_strides()
+{
+    let ptr = std::ptr::dangling_mut::<f64>();
+    let view = unsafe { ArrayViewMut2::from_shape_ptr((2, 0).strides((0, 0)), ptr) };
+    assert_eq!(view.shape(), &[2, 0]);
+}
+
 #[should_panic(expected = "Unsupported")]
 #[cfg(debug_assertions)]
 #[test]