From 597ae6ae08e21b79aa02cb8099092b4e82ca2d31 Mon Sep 17 00:00:00 2001
From: jamie2779 <jamie2779@naver.com>
Date: Fri, 15 Aug 2025 15:05:22 +0900
Subject: [PATCH 1/3] allow memoryview cast for F-contiguous

---
 Lib/test/test_buffer.py | 26 ++++++++++++++++++++++++++
 Objects/memoryobject.c  |  8 +++++---
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index 19582e757161fc..cdb1f575ff573c 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -2846,6 +2846,32 @@ class BEPoint(ctypes.BigEndianStructure):
             self.assertEqual(m2.strides, (1,))
             self.assertEqual(m2.suboffsets, ())
 
+    def test_memoryview_cast_f_contiguous_ND_1D(self):
+        nd = ndarray(list(range(12)),shape=[3, 4], format='B', flags=ND_FORTRAN)
+        m = memoryview(nd)
+        self.assertTrue(m.f_contiguous)
+        self.assertTrue(m.contiguous)
+
+        m1 = m.cast('B')
+        self.assertEqual(m1.ndim, 1)
+        self.assertEqual(m1.shape, (m.nbytes,))
+        self.assertEqual(m1.strides, (1,))
+        self.assertTrue(m1.c_contiguous)
+        self.assertTrue(m1.contiguous)
+        self.assertEqual(m1.tobytes(), memoryview(nd).tobytes(order='F'))
+
+        for fmt in ('B', 'b', 'c', 'H', 'I'):
+            size = struct.calcsize(fmt)
+            if m.nbytes % size == 0:
+                m2 = m.cast(fmt)
+                self.assertEqual(m2.ndim, 1)
+                self.assertEqual(m2.shape, (m.nbytes // size,))
+                self.assertTrue(m2.contiguous)
+        
+        m3 = m[::-1]
+        with self.assertRaises(TypeError):
+            m3.cast('B')
+
     def test_memoryview_tolist(self):
 
         # Most tolist() tests are in self.verify() etc.
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index cf673fb379edcd..c5971eb82ad5ff 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -1456,9 +1456,11 @@ memoryview_cast_impl(PyMemoryViewObject *self, PyObject *format,
     CHECK_RESTRICTED(self);
 
     if (!MV_C_CONTIGUOUS(self->flags)) {
-        PyErr_SetString(PyExc_TypeError,
-            "memoryview: casts are restricted to C-contiguous views");
-        return NULL;
+        if(shape || self->view.ndim == 1 || !MV_F_CONTIGUOUS(self->flags)) {
+            PyErr_SetString(PyExc_TypeError,
+                "memoryview: casts are restricted to C-contiguous views");
+            return NULL;
+        }
     }
     if ((shape || self->view.ndim != 1) && zero_in_shape(self)) {
         PyErr_SetString(PyExc_TypeError,

From 3cc8a7ec723fa66d64cb5b59a82da30280d97eee Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Fri, 15 Aug 2025 06:28:46 +0000
Subject: [PATCH 2/3] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../2025-08-15-06-28-45.gh-issue-91484.huCgHt.rst                | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2025-08-15-06-28-45.gh-issue-91484.huCgHt.rst

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-08-15-06-28-45.gh-issue-91484.huCgHt.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-08-15-06-28-45.gh-issue-91484.huCgHt.rst
new file mode 100644
index 00000000000000..0131095ac44b3e
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-08-15-06-28-45.gh-issue-91484.huCgHt.rst
@@ -0,0 +1 @@
+memoryview.cast() now allows casting from N-D to 1-D for F-contiguous.

From 20df3ab5cd12336d1daae16a23791bb55b40c762 Mon Sep 17 00:00:00 2001
From: jamie2779 <jamie2779@naver.com>
Date: Fri, 15 Aug 2025 15:47:16 +0900
Subject: [PATCH 3/3] fix lint issue

---
 Lib/test/test_buffer.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index cdb1f575ff573c..cac2f801e6dd45 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -2867,7 +2867,7 @@ def test_memoryview_cast_f_contiguous_ND_1D(self):
                 self.assertEqual(m2.ndim, 1)
                 self.assertEqual(m2.shape, (m.nbytes // size,))
                 self.assertTrue(m2.contiguous)
-        
+
         m3 = m[::-1]
         with self.assertRaises(TypeError):
             m3.cast('B')