numpy · seberg · Mar 3, 2025 · Feb 18, 2025 · Feb 21, 2025 · Feb 27, 2025
diff --git a/numpy/_core/src/multiarray/compiled_base.c b/numpy/_core/src/multiarray/compiled_base.c
@@ -119,6 +119,7 @@ arr_bincount(PyObject *NPY_UNUSED(self), PyObject *const *args,
    npy_intp *numbers, *ians, len, mx, mn, ans_size;
    npy_intp minlength = 0;
    npy_intp i;
+    int flags;
    double *weights , *dans;

    NPY_PREPARE_ARGPARSER;
@@ -177,7 +178,13 @@ arr_bincount(PyObject *NPY_UNUSED(self), PyObject *const *args,
    }

    if (lst == NULL) {
-        lst = (PyArrayObject *)PyArray_ContiguousFromAny(list, NPY_INTP, 1, 1);
+        flags = NPY_ARRAY_WRITEABLE | NPY_ARRAY_ALIGNED | NPY_ARRAY_C_CONTIGUOUS;
+        if (PyArray_Size((PyObject *)list) &&
+            PyArray_ISINTEGER((PyArrayObject *)list)) {
+            flags = flags | NPY_ARRAY_FORCECAST;
+        }
+        PyArray_Descr* local_dtype = PyArray_DescrFromType(NPY_INTP);
+        lst = (PyArrayObject *)PyArray_FromAny(list, local_dtype, 1, 1, flags, NULL);
        if (lst == NULL) {
            goto fail;
        }

diff --git a/numpy/lib/tests/test_function_base.py b/numpy/lib/tests/test_function_base.py
@@ -2959,6 +2959,17 @@ def test_error_not_1d(self, vals):
        with assert_raises(ValueError):
            np.bincount(vals)

+    @pytest.mark.parametrize("dt", np.typecodes["AllInteger"])
+    def test_gh_28354(self, dt):
+        a = np.array([0, 1, 1, 3, 2, 1, 7], dtype=dt)
+        actual = np.bincount(a)
+        expected = [1, 3, 1, 1, 0, 0, 0, 1]
+        assert_array_equal(actual, expected)
+
+    def test_contiguous_handling(self):
+        # check for absence of hard crash
+        np.bincount(np.arange(10000)[::2])
+

 class TestInterp:
-Original file line number
+Diff line change
@@ -119,6 +119,7 @@ arr_bincount(PyObject *NPY_UNUSED(self), PyObject *const *args,
         npy_intp *numbers, *ians, len, mx, mn, ans_size;
         npy_intp minlength = 0;
         npy_intp i;
+        int flags;
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            seberg
  

      

      

      


        Feb 24, 2025


      
    

  


        
      
  
  
  
    

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      Would move this down into the if, but OK.
I think we can put this in, if we change things to a PyArray_Check below, unless I am missing something.  It seems fine, even if it might not be 100% for array-likes.
I would lean towards not backporting.  It has been around forever, and the reason it came up was just cupy testing against NumPy as far as I am aware.
    
  
  


    

        
      
  
  
    
  
  
  
    
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         double *weights , *dans;
         NPY_PREPARE_ARGPARSER;
@@ -177,7 +178,13 @@ arr_bincount(PyObject *NPY_UNUSED(self), PyObject *const *args,
         }
         if (lst == NULL) {
-            lst = (PyArrayObject *)PyArray_ContiguousFromAny(list, NPY_INTP, 1, 1);
+            flags = NPY_ARRAY_WRITEABLE | NPY_ARRAY_ALIGNED | NPY_ARRAY_C_CONTIGUOUS;
+            if (PyArray_Size((PyObject *)list) &&
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            seberg
  

      

      

      


        Feb 24, 2025


      
    

  


        
      
  
  
  
    

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      The deprecation makes this pretty messy, almost wondering if we should just finalize it...
In either case, I think the PyArray_Size() here ends up as an imprecise PyArray_Check() here (as it misses an empty uint8 array for example)?
I am not quite sure that not setting force-cast in the non-array case won't finalize the deprecation (in small parts).

Since both paths use PyArray_ContiguousFromAny, I think that is fine.  Although, it may be that we are not relaxing allowing uint64 for an array-like here i.e. something like:
class a:
    def __array__(self):
        return np.ones(10, dtype=np.uint64)

    
  
  


    

        
      
  
  
    
  
  
  
    
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+                PyArray_ISINTEGER((PyArrayObject *)list)) {
+                flags = flags | NPY_ARRAY_FORCECAST;
+            }
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+            PyArray_Descr* local_dtype = PyArray_DescrFromType(NPY_INTP);
+            lst = (PyArrayObject *)PyArray_FromAny(list, local_dtype, 1, 1, flags, NULL);
             if (lst == NULL) {
                 goto fail;
             }
-          Expand Down