BUG: don't use PyArray_Converter in may_share_memory

The converter function has NPY_ARRAY_CARRAY enabled, which can cause
false negatives for non-ndarray inputs.

Fixes gh-5604

2 files changed, 56 insertions, 4 deletions

diff --git a/numpy/core/src/multiarray/multiarraymodule.c b/numpy/core/src/multiarray/multiarraymodule.c
index 486fdbc9b..b9d79029e 100644
--- a/numpy/core/src/multiarray/multiarraymodule.c
+++ b/numpy/core/src/multiarray/multiarraymodule.c
@@ -3992,6 +3992,8 @@ static PyObject *
 array_shares_memory_impl(PyObject *args, PyObject *kwds, Py_ssize_t default_max_work,
                          int raise_exceptions)
 {
+    PyObject * self_obj = NULL;
+    PyObject * other_obj = NULL;
     PyArrayObject * self = NULL;
     PyArrayObject * other = NULL;
     PyObject *max_work_obj = NULL;
@@ -4004,13 +4006,35 @@ array_shares_memory_impl(PyObject *args, PyObject *kwds, Py_ssize_t default_max_
 
     max_work = default_max_work;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&O&|O", kwlist,
-                                     PyArray_Converter, &self,
-                                     PyArray_Converter, &other,
-                                     &max_work_obj)) {
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO|O", kwlist,
+                                     &self_obj, &other_obj, &max_work_obj)) {
         return NULL;
     }
 
+    if (PyArray_Check(self_obj)) {
+        self = (PyArrayObject*)self_obj;
+        Py_INCREF(self);
+    }
+    else {
+        /* Use FromAny to enable checking overlap for objects exposing array
+           interfaces etc. */
+        self = (PyArrayObject*)PyArray_FromAny(self_obj, NULL, 0, 0, 0, NULL);
+        if (self == NULL) {
+            goto fail;
+        }
+    }
+
+    if (PyArray_Check(other_obj)) {
+        other = (PyArrayObject*)other_obj;
+        Py_INCREF(other);
+    }
+    else {
+        other = (PyArrayObject*)PyArray_FromAny(other_obj, NULL, 0, 0, 0, NULL);
+        if (other == NULL) {
+            goto fail;
+        }
+    }
+
     if (max_work_obj == NULL || max_work_obj == Py_None) {
         /* noop */
     }
diff --git a/numpy/core/tests/test_mem_overlap.py b/numpy/core/tests/test_mem_overlap.py
index 728cc675d..8d39fa4c0 100644
--- a/numpy/core/tests/test_mem_overlap.py
+++ b/numpy/core/tests/test_mem_overlap.py
@@ -482,5 +482,33 @@ def test_internal_overlap_fuzz():
             no_overlap += 1
 
 
+def test_non_ndarray_inputs():
+    # Regression check for gh-5604
+
+    class MyArray(object):
+        def __init__(self, data):
+            self.data = data
+
+        @property
+        def __array_interface__(self):
+            return self.data.__array_interface__
+
+    class MyArray2(object):
+        def __init__(self, data):
+            self.data = data
+
+        def __array__(self):
+            return self.data
+
+    for cls in [MyArray, MyArray2]:
+        x = np.arange(5)
+
+        assert_(np.may_share_memory(cls(x[::2]), x[1::2]))
+        assert_(not np.shares_memory(cls(x[::2]), x[1::2]))
+
+        assert_(np.shares_memory(cls(x[1::3]), x[::2]))
+        assert_(np.may_share_memory(cls(x[1::3]), x[::2]))
+
+
 if __name__ == "__main__":
     run_module_suite()