From ca76251558cef8e6b5731a1f9f3e86d32e2ff3ac Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Sun, 2 Oct 2022 15:43:42 -0700
Subject: [PATCH 01/35] try 1

---
 Include/internal/pycore_global_strings.h |   2 +
 Objects/typeobject.c                     | 106 ++++++++++++++++++++++-
 2 files changed, 106 insertions(+), 2 deletions(-)

diff --git a/Include/internal/pycore_global_strings.h b/Include/internal/pycore_global_strings.h
index 1523eef73931c9..f79e6ad2d53827 100644
--- a/Include/internal/pycore_global_strings.h
+++ b/Include/internal/pycore_global_strings.h
@@ -74,6 +74,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(__await__)
         STRUCT_FOR_ID(__bases__)
         STRUCT_FOR_ID(__bool__)
+        STRUCT_FOR_ID(__buffer__)
         STRUCT_FOR_ID(__build_class__)
         STRUCT_FOR_ID(__builtins__)
         STRUCT_FOR_ID(__bytes__)
@@ -172,6 +173,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(__rdivmod__)
         STRUCT_FOR_ID(__reduce__)
         STRUCT_FOR_ID(__reduce_ex__)
+        STRUCT_FOR_ID(__release_buffer__) 
         STRUCT_FOR_ID(__repr__)
         STRUCT_FOR_ID(__reversed__)
         STRUCT_FOR_ID(__rfloordiv__)
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 5aa5cbbd54022e..fc3e0f42d884c4 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -7551,6 +7551,46 @@ wrap_descr_delete(PyObject *self, PyObject *args, void *wrapped)
     Py_RETURN_NONE;
 }
 
+static PyObject *
+wrap_buffer(PyObject *self, PyObject *args, void *wrapped)
+{
+    getbufferproc func = (getbufferproc)wrapped;
+    Py_buffer view;
+    int flags = 0;
+
+    if (!check_num_args(args, 1)) {
+        return NULL;
+    }
+    if (!PyArg_ParseTuple(args, "i", &flags)) {
+        return NULL;
+    }
+    if ((*func)(self, &view, flags) < 0) {
+        return NULL;
+    }
+    return PyMemoryView_FromBuffer(&view);
+}
+
+static PyObject *
+wrap_releasebuffer(PyObject *self, PyObject *args, void *wrapped)
+{
+    releasebufferproc func = (releasebufferproc)wrapped;
+    PyMemoryViewObject *mview;
+
+    if (!check_num_args(args, 1)) {
+        return NULL;
+    }
+    if (!PyArg_ParseTuple(args, "O!", &PyMemoryView_Type, &mview)) {
+        return NULL;
+    }
+    if (mview->view.obj != self) {
+        PyErr_SetString(PyExc_ValueError,
+                        "memoryview's buffer is not this object");
+        return NULL;
+    }
+    (*func)(self, &mview->view);
+    Py_RETURN_NONE;
+}
+
 static PyObject *
 wrap_init(PyObject *self, PyObject *args, void *wrapped, PyObject *kwds)
 {
@@ -8383,6 +8423,54 @@ slot_tp_finalize(PyObject *self)
     PyErr_Restore(error_type, error_value, error_traceback);
 }
 
+static int 
+slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
+{
+    PyObject *flags_obj = PyLong_FromLong(flags);
+    if (flags_obj == NULL) {
+        return -1;
+    }
+    PyObject *stack[2] = {self, flags_obj};
+    PyObject *ret = vectorcall_method(&_Py_ID(__buffer__), stack, 2);
+    if (ret == NULL) {
+        goto fail;
+    }
+    if (!PyMemoryView_Check(ret)) {
+        PyErr_Format(PyExc_TypeError,
+                     "__buffer__ returned non-memoryview object");
+        goto fail;
+    }
+    *buffer = ((PyMemoryViewObject *)ret)->view;
+    Py_DECREF(ret);
+    Py_DECREF(flags_obj);
+    return 0;
+
+fail:
+    Py_XDECREF(ret);
+    Py_DECREF(flags_obj);
+    return -1;
+}
+
+static void
+slot_bf_releasebuffer(PyObject *self, Py_buffer *buffer)
+{
+    PyObject *mv = PyMemoryView_FromBuffer(buffer);
+    if (mv == NULL) {
+        PyErr_WriteUnraisable(self);
+        return;
+    }
+    PyObject *stack[2] = {self, mv};
+    PyObject *ret = vectorcall_method(&_Py_ID(__release_buffer__), stack, 2);
+    Py_DECREF(mv);
+    if (ret == NULL) {
+        PyErr_WriteUnraisable(self);
+    }
+    else {
+        Py_DECREF(ret);
+    }
+}
+
+
 static PyObject *
 slot_am_await(PyObject *self)
 {
@@ -8452,6 +8540,7 @@ typedef struct wrapperbase slotdef;
 
 #undef TPSLOT
 #undef FLSLOT
+#undef BUFSLOT
 #undef AMSLOT
 #undef ETSLOT
 #undef SQSLOT
@@ -8471,6 +8560,8 @@ typedef struct wrapperbase slotdef;
 #define ETSLOT(NAME, SLOT, FUNCTION, WRAPPER, DOC) \
     {#NAME, offsetof(PyHeapTypeObject, SLOT), (void *)(FUNCTION), WRAPPER, \
      PyDoc_STR(DOC), .name_strobj = &_Py_ID(NAME) }
+#define BUFSLOT(NAME, SLOT, FUNCTION, WRAPPER, DOC) \
+    ETSLOT(NAME, as_buffer.SLOT, FUNCTION, WRAPPER, DOC)
 #define AMSLOT(NAME, SLOT, FUNCTION, WRAPPER, DOC) \
     ETSLOT(NAME, as_async.SLOT, FUNCTION, WRAPPER, DOC)
 #define SQSLOT(NAME, SLOT, FUNCTION, WRAPPER, DOC) \
@@ -8552,6 +8643,13 @@ static slotdef slotdefs[] = {
            "Create and return new object.  See help(type) for accurate signature."),
     TPSLOT(__del__, tp_finalize, slot_tp_finalize, (wrapperfunc)wrap_del, ""),
 
+    BUFSLOT(__buffer__, bf_getbuffer, slot_bf_getbuffer, wrap_buffer,
+            "__buffer__($self, flags, /)\n--\n\n"
+            "Return a buffer object that exposes the underlying memory of the object."),
+    BUFSLOT(__release_buffer__, bf_releasebuffer, slot_bf_releasebuffer, wrap_releasebuffer,
+            "__release_buffer__($self, /)\n--\n\n"
+            "Release the buffer object that exposes the underlying memory of the object."), 
+
     AMSLOT(__await__, am_await, slot_am_await, wrap_unaryfunc,
            "__await__($self, /)\n--\n\nReturn an iterator to be used in await expression."),
     AMSLOT(__aiter__, am_aiter, slot_am_aiter, wrap_unaryfunc,
@@ -8698,8 +8796,12 @@ slotptr(PyTypeObject *type, int ioffset)
 
     /* Note: this depends on the order of the members of PyHeapTypeObject! */
     assert(offset >= 0);
-    assert((size_t)offset < offsetof(PyHeapTypeObject, as_buffer));
-    if ((size_t)offset >= offsetof(PyHeapTypeObject, as_sequence)) {
+    assert((size_t)offset < offsetof(PyHeapTypeObject, ht_name));
+    if ((size_t)offset >= offsetof(PyHeapTypeObject, as_buffer)) {
+        ptr = (char *)type->tp_as_buffer;
+        offset -= offsetof(PyHeapTypeObject, as_buffer);
+    }
+    else if ((size_t)offset >= offsetof(PyHeapTypeObject, as_sequence)) {
         ptr = (char *)type->tp_as_sequence;
         offset -= offsetof(PyHeapTypeObject, as_sequence);
     }

From 901b459cd92e224afddc5291e3670cd0efdd3511 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Mon, 3 Oct 2022 11:50:52 -0700
Subject: [PATCH 02/35] progress

---
 Include/internal/pycore_global_strings.h      |  2 +-
 Include/internal/pycore_memoryobject.h        | 17 +++++++
 .../internal/pycore_runtime_init_generated.h  | 14 +++++
 Lib/test/test_buffer.py                       | 51 +++++++++++++++++++
 Objects/memoryobject.c                        | 21 +++++---
 Objects/typeobject.c                          | 15 +++---
 6 files changed, 106 insertions(+), 14 deletions(-)
 create mode 100644 Include/internal/pycore_memoryobject.h

diff --git a/Include/internal/pycore_global_strings.h b/Include/internal/pycore_global_strings.h
index f79e6ad2d53827..45068c5aabe960 100644
--- a/Include/internal/pycore_global_strings.h
+++ b/Include/internal/pycore_global_strings.h
@@ -173,7 +173,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(__rdivmod__)
         STRUCT_FOR_ID(__reduce__)
         STRUCT_FOR_ID(__reduce_ex__)
-        STRUCT_FOR_ID(__release_buffer__) 
+        STRUCT_FOR_ID(__release_buffer__)
         STRUCT_FOR_ID(__repr__)
         STRUCT_FOR_ID(__reversed__)
         STRUCT_FOR_ID(__rfloordiv__)
diff --git a/Include/internal/pycore_memoryobject.h b/Include/internal/pycore_memoryobject.h
new file mode 100644
index 00000000000000..acc12c9275172c
--- /dev/null
+++ b/Include/internal/pycore_memoryobject.h
@@ -0,0 +1,17 @@
+#ifndef Py_INTERNAL_MEMORYOBJECT_H
+#define Py_INTERNAL_MEMORYOBJECT_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
+PyObject *
+PyMemoryView_FromObjectAndFlags(PyObject *v, int flags);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_INTERNAL_MEMORYOBJECT_H */
diff --git a/Include/internal/pycore_runtime_init_generated.h b/Include/internal/pycore_runtime_init_generated.h
index 32ff57b731e1a0..662ff2b3151b84 100644
--- a/Include/internal/pycore_runtime_init_generated.h
+++ b/Include/internal/pycore_runtime_init_generated.h
@@ -583,6 +583,7 @@ extern "C" {
                 INIT_ID(__await__), \
                 INIT_ID(__bases__), \
                 INIT_ID(__bool__), \
+                INIT_ID(__buffer__), \
                 INIT_ID(__build_class__), \
                 INIT_ID(__builtins__), \
                 INIT_ID(__bytes__), \
@@ -681,6 +682,7 @@ extern "C" {
                 INIT_ID(__rdivmod__), \
                 INIT_ID(__reduce__), \
                 INIT_ID(__reduce_ex__), \
+                INIT_ID(__release_buffer__), \
                 INIT_ID(__repr__), \
                 INIT_ID(__reversed__), \
                 INIT_ID(__rfloordiv__), \
@@ -1472,6 +1474,8 @@ _PyUnicode_InitStaticStrings(void) {
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__bool__);
     PyUnicode_InternInPlace(&string);
+    string = &_Py_ID(__buffer__);
+    PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__build_class__);
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__builtins__);
@@ -1668,6 +1672,8 @@ _PyUnicode_InitStaticStrings(void) {
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__reduce_ex__);
     PyUnicode_InternInPlace(&string);
+    string = &_Py_ID(__release_buffer__);
+    PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__repr__);
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__reversed__);
@@ -4871,6 +4877,10 @@ _PyStaticObjects_CheckRefcnt(void) {
         _PyObject_Dump((PyObject *)&_Py_ID(__bool__));
         Py_FatalError("immortal object has less refcnt than expected _PyObject_IMMORTAL_REFCNT");
     };
+    if (Py_REFCNT((PyObject *)&_Py_ID(__buffer__)) < _PyObject_IMMORTAL_REFCNT) {
+        _PyObject_Dump((PyObject *)&_Py_ID(__buffer__));
+        Py_FatalError("immortal object has less refcnt than expected _PyObject_IMMORTAL_REFCNT");
+    };
     if (Py_REFCNT((PyObject *)&_Py_ID(__build_class__)) < _PyObject_IMMORTAL_REFCNT) {
         _PyObject_Dump((PyObject *)&_Py_ID(__build_class__));
         Py_FatalError("immortal object has less refcnt than expected _PyObject_IMMORTAL_REFCNT");
@@ -5263,6 +5273,10 @@ _PyStaticObjects_CheckRefcnt(void) {
         _PyObject_Dump((PyObject *)&_Py_ID(__reduce_ex__));
         Py_FatalError("immortal object has less refcnt than expected _PyObject_IMMORTAL_REFCNT");
     };
+    if (Py_REFCNT((PyObject *)&_Py_ID(__release_buffer__)) < _PyObject_IMMORTAL_REFCNT) {
+        _PyObject_Dump((PyObject *)&_Py_ID(__release_buffer__));
+        Py_FatalError("immortal object has less refcnt than expected _PyObject_IMMORTAL_REFCNT");
+    };
     if (Py_REFCNT((PyObject *)&_Py_ID(__repr__)) < _PyObject_IMMORTAL_REFCNT) {
         _PyObject_Dump((PyObject *)&_Py_ID(__repr__));
         Py_FatalError("immortal object has less refcnt than expected _PyObject_IMMORTAL_REFCNT");
diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index 8ac3b7e7eb29d1..a1b624aef4605c 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4436,5 +4436,56 @@ def test_pybuffer_size_from_format(self):
                              struct.calcsize(format))
 
 
+class TestPythonBufferProtocol(unittest.TestCase):
+    def test_basic(self):
+        class MyBuffer:
+            def __buffer__(self, flags):
+                return memoryview(b"hello")
+
+        mv = memoryview(MyBuffer())
+        self.assertEqual(mv.tobytes(), b"hello")
+        self.assertEqual(bytes(MyBuffer()), b"hello")
+
+    def test_bad_buffer_method(self):
+        class MustReturnMV:
+            def __buffer__(self, flags):
+                return 42
+
+        self.assertRaises(TypeError, memoryview, MustReturnMV())
+
+        class WrongArity:
+            def __buffer__(self):
+                return memoryview(b"hello")
+
+        self.assertRaises(TypeError, memoryview, WrongArity())
+
+    def test_release_buffer(self):
+        class WhatToRelease:
+            def __init__(self):
+                self.held = False
+                self.ba = bytearray(b"hello")
+            def __buffer__(self, flags):
+                if self.held:
+                    raise TypeError("already held")
+                self.held = True
+                return memoryview(self.ba)
+            def __release_buffer__(self, buffer):
+                assert self is buffer.obj
+                self.held = False
+
+        wr = WhatToRelease()
+        self.assertFalse(wr.held)
+        with memoryview(wr) as mv:
+            self.assertTrue(wr.held)
+            self.assertEqual(mv.tobytes(), b"hello")
+        self.assertFalse(wr.held)
+
+    def test_call_builtins(self):
+        ba = bytearray(b"hello")
+        mv = ba.__buffer__(0)
+        self.assertEqual(mv.tobytes(), b"hello")
+        ba.__release_buffer__(mv)
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index c5ab0bf2dedbe4..db832aa5c9b22a 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -85,7 +85,7 @@ mbuf_alloc(void)
 }
 
 static PyObject *
-_PyManagedBuffer_FromObject(PyObject *base)
+_PyManagedBuffer_FromObject(PyObject *base, int flags)
 {
     _PyManagedBufferObject *mbuf;
 
@@ -93,7 +93,7 @@ _PyManagedBuffer_FromObject(PyObject *base)
     if (mbuf == NULL)
         return NULL;
 
-    if (PyObject_GetBuffer(base, &mbuf->master, PyBUF_FULL_RO) < 0) {
+    if (PyObject_GetBuffer(base, &mbuf->master, flags) < 0) {
         mbuf->master.obj = NULL;
         Py_DECREF(mbuf);
         return NULL;
@@ -779,11 +779,12 @@ PyMemoryView_FromBuffer(const Py_buffer *info)
     return mv;
 }
 
-/* Create a memoryview from an object that implements the buffer protocol.
+/* Create a memoryview from an object that implements the buffer protocol,
+   using the given flags.
    If the object is a memoryview, the new memoryview must be registered
    with the same managed buffer. Otherwise, a new managed buffer is created. */
 PyObject *
-PyMemoryView_FromObject(PyObject *v)
+PyMemoryView_FromObjectAndFlags(PyObject *v, int flags)
 {
     _PyManagedBufferObject *mbuf;
 
@@ -794,7 +795,7 @@ PyMemoryView_FromObject(PyObject *v)
     }
     else if (PyObject_CheckBuffer(v)) {
         PyObject *ret;
-        mbuf = (_PyManagedBufferObject *)_PyManagedBuffer_FromObject(v);
+        mbuf = (_PyManagedBufferObject *)_PyManagedBuffer_FromObject(v, flags);
         if (mbuf == NULL)
             return NULL;
         ret = mbuf_add_view(mbuf, NULL);
@@ -807,6 +808,14 @@ PyMemoryView_FromObject(PyObject *v)
         Py_TYPE(v)->tp_name);
     return NULL;
 }
+/* Create a memoryview from an object that implements the buffer protocol.
+   If the object is a memoryview, the new memoryview must be registered
+   with the same managed buffer. Otherwise, a new managed buffer is created. */
+PyObject *
+PyMemoryView_FromObject(PyObject *v)
+{
+    return PyMemoryView_FromObjectAndFlags(v, PyBUF_FULL_RO);
+}
 
 /* Copy the format string from a base object that might vanish. */
 static int
@@ -853,7 +862,7 @@ memory_from_contiguous_copy(const Py_buffer *src, char order)
     if (bytes == NULL)
         return NULL;
 
-    mbuf = (_PyManagedBufferObject *)_PyManagedBuffer_FromObject(bytes);
+    mbuf = (_PyManagedBufferObject *)_PyManagedBuffer_FromObject(bytes, PyBUF_FULL_RO);
     Py_DECREF(bytes);
     if (mbuf == NULL)
         return NULL;
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index fc3e0f42d884c4..48baac313151d9 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -5,6 +5,7 @@
 #include "pycore_code.h"          // CO_FAST_FREE
 #include "pycore_compile.h"       // _Py_Mangle()
 #include "pycore_initconfig.h"    // _PyStatus_OK()
+#include "pycore_memoryobject.h"  // PyMemoryView_FromObjectAndFlags()
 #include "pycore_moduleobject.h"  // _PyModule_GetDef()
 #include "pycore_object.h"        // _PyType_HasFeature()
 #include "pycore_pyerrors.h"      // _PyErr_Occurred()
@@ -7554,8 +7555,6 @@ wrap_descr_delete(PyObject *self, PyObject *args, void *wrapped)
 static PyObject *
 wrap_buffer(PyObject *self, PyObject *args, void *wrapped)
 {
-    getbufferproc func = (getbufferproc)wrapped;
-    Py_buffer view;
     int flags = 0;
 
     if (!check_num_args(args, 1)) {
@@ -7564,10 +7563,7 @@ wrap_buffer(PyObject *self, PyObject *args, void *wrapped)
     if (!PyArg_ParseTuple(args, "i", &flags)) {
         return NULL;
     }
-    if ((*func)(self, &view, flags) < 0) {
-        return NULL;
-    }
-    return PyMemoryView_FromBuffer(&view);
+    return PyMemoryView_FromObjectAndFlags(self, flags);
 }
 
 static PyObject *
@@ -8441,6 +8437,9 @@ slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
         goto fail;
     }
     *buffer = ((PyMemoryViewObject *)ret)->view;
+    // TODO does this leak the existing ref in buffer->obj?
+    buffer->obj = self;
+    Py_INCREF(buffer->obj);
     Py_DECREF(ret);
     Py_DECREF(flags_obj);
     return 0;
@@ -8459,6 +8458,9 @@ slot_bf_releasebuffer(PyObject *self, Py_buffer *buffer)
         PyErr_WriteUnraisable(self);
         return;
     }
+    if (buffer->obj != NULL) {
+        ((PyMemoryViewObject *)mv)->view.obj = Py_NewRef(buffer->obj);
+    }
     PyObject *stack[2] = {self, mv};
     PyObject *ret = vectorcall_method(&_Py_ID(__release_buffer__), stack, 2);
     Py_DECREF(mv);
@@ -8470,7 +8472,6 @@ slot_bf_releasebuffer(PyObject *self, Py_buffer *buffer)
     }
 }
 
-
 static PyObject *
 slot_am_await(PyObject *self)
 {

From c5407c7dfb30d6926569a21b00c0c0ccf5b2e89a Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 4 Oct 2022 10:37:50 -0700
Subject: [PATCH 03/35] this is better

---
 Lib/test/test_buffer.py | 2 +-
 Objects/typeobject.c    | 2 --
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index a1b624aef4605c..bd6bca1f48d0d5 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4478,7 +4478,7 @@ def __release_buffer__(self, buffer):
         with memoryview(wr) as mv:
             self.assertTrue(wr.held)
             self.assertEqual(mv.tobytes(), b"hello")
-        self.assertFalse(wr.held)
+        #self.assertFalse(wr.held)
 
     def test_call_builtins(self):
         ba = bytearray(b"hello")
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 48baac313151d9..24b260d2a3cb83 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8437,8 +8437,6 @@ slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
         goto fail;
     }
     *buffer = ((PyMemoryViewObject *)ret)->view;
-    // TODO does this leak the existing ref in buffer->obj?
-    buffer->obj = self;
     Py_INCREF(buffer->obj);
     Py_DECREF(ret);
     Py_DECREF(flags_obj);

From 86f2000a67fa1f990dbae3cc7400ea4fa042cec8 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 4 Oct 2022 16:59:28 -0700
Subject: [PATCH 04/35] this seems to work

---
 Include/internal/pycore_typeobject.h |  2 +
 Lib/_collections_abc.py              | 32 ++++++++++-
 Lib/test/test_buffer.py              |  3 +-
 Lib/test/test_collections.py         | 18 ++++++-
 Objects/object.c                     |  2 +
 Objects/typeobject.c                 | 80 ++++++++++++++++++++++++++--
 6 files changed, 128 insertions(+), 9 deletions(-)

diff --git a/Include/internal/pycore_typeobject.h b/Include/internal/pycore_typeobject.h
index 5e7aca1b9f5ae9..97309650c895c1 100644
--- a/Include/internal/pycore_typeobject.h
+++ b/Include/internal/pycore_typeobject.h
@@ -75,6 +75,8 @@ extern void _PyStaticType_Dealloc(PyTypeObject *type);
 PyObject *_Py_slot_tp_getattro(PyObject *self, PyObject *name);
 PyObject *_Py_slot_tp_getattr_hook(PyObject *self, PyObject *name);
 
+PyAPI_DATA(PyTypeObject) _PyBufferWrapper_Type;
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py
index c62233b81a5c95..3b0d0eeb1fa9d1 100644
--- a/Lib/_collections_abc.py
+++ b/Lib/_collections_abc.py
@@ -49,7 +49,7 @@ def _f(): pass
            "Mapping", "MutableMapping",
            "MappingView", "KeysView", "ItemsView", "ValuesView",
            "Sequence", "MutableSequence",
-           "ByteString",
+           "ByteString", "Buffer", "MutableBuffer",
            ]
 
 # This module has been renamed from collections.abc to _collections_abc to
@@ -439,6 +439,36 @@ def __subclasshook__(cls, C):
         return NotImplemented
 
 
+class Buffer(metaclass=ABCMeta):
+
+    __slots__ = ()
+
+    @abstractmethod
+    def __buffer__(self, flags: int, /) -> memoryview:
+        raise NotImplementedError
+
+    @classmethod
+    def __subclasshook__(cls, C):
+        if cls is Buffer:
+            return _check_methods(C, "__buffer__")
+        return NotImplemented
+
+
+class MutableBuffer(Buffer):
+
+    __slots__ = ()
+
+    @abstractmethod
+    def __release_buffer__(self, buffer: memoryview, /) -> None:
+        pass
+
+    @classmethod
+    def __subclasshook__(cls, C):
+        if cls is MutableBuffer:
+            return _check_methods(C, "__buffer__", "__release_buffer__")
+        return NotImplemented
+
+
 class _CallableGenericAlias(GenericAlias):
     """ Represent `Callable[argtypes, resulttype]`.
 
diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index bd6bca1f48d0d5..c46045ae96485e 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4470,7 +4470,6 @@ def __buffer__(self, flags):
                 self.held = True
                 return memoryview(self.ba)
             def __release_buffer__(self, buffer):
-                assert self is buffer.obj
                 self.held = False
 
         wr = WhatToRelease()
@@ -4478,7 +4477,7 @@ def __release_buffer__(self, buffer):
         with memoryview(wr) as mv:
             self.assertTrue(wr.held)
             self.assertEqual(mv.tobytes(), b"hello")
-        #self.assertFalse(wr.held)
+        self.assertFalse(wr.held)
 
     def test_call_builtins(self):
         ba = bytearray(b"hello")
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 59b3f2ec7bfcb6..a8ea91d973638f 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -25,7 +25,7 @@
 from collections.abc import Set, MutableSet
 from collections.abc import Mapping, MutableMapping, KeysView, ItemsView, ValuesView
 from collections.abc import Sequence, MutableSequence
-from collections.abc import ByteString
+from collections.abc import ByteString, Buffer, MutableBuffer
 
 
 class TestUserObjects(unittest.TestCase):
@@ -1941,6 +1941,22 @@ def test_ByteString(self):
         self.assertNotIsInstance(memoryview(b""), ByteString)
         self.assertFalse(issubclass(memoryview, ByteString))
 
+    def test_Buffer(self):
+        for sample in [bytes, bytearray, memoryview]:
+            self.assertIsInstance(sample(b"x"), Buffer)
+            self.assertTrue(issubclass(sample, Buffer))
+        for sample in [str, list, tuple]:
+            self.assertNotIsInstance(sample(), Buffer)
+            self.assertFalse(issubclass(sample, Buffer))
+
+    def test_MutableBuffer(self):
+        for sample in [bytearray, memoryview]:
+            self.assertIsInstance(sample(b"x"), MutableBuffer)
+            self.assertTrue(issubclass(sample, MutableBuffer))
+        for sample in [bytes, str, list, tuple]:
+            self.assertNotIsInstance(sample(), MutableBuffer)
+            self.assertFalse(issubclass(sample, MutableBuffer))
+
     def test_MutableSequence(self):
         for sample in [tuple, str, bytes]:
             self.assertNotIsInstance(sample(), MutableSequence)
diff --git a/Objects/object.c b/Objects/object.c
index 26cdcef59dddbd..5edbe34025daa6 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -14,6 +14,7 @@
 #include "pycore_pymem.h"         // _PyMem_IsPtrFreed()
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 #include "pycore_symtable.h"      // PySTEntry_Type
+#include "pycore_typeobject.h"    // _PyBufferWrapper_Type
 #include "pycore_unionobject.h"   // _PyUnion_Type
 #include "pycore_interpreteridobject.h"  // _PyInterpreterID_Type
 
@@ -1930,6 +1931,7 @@ static PyTypeObject* static_types[] = {
     &_PyAsyncGenASend_Type,
     &_PyAsyncGenAThrow_Type,
     &_PyAsyncGenWrappedValue_Type,
+    &_PyBufferWrapper_Type,
     &_PyContextTokenMissing_Type,
     &_PyCoroWrapper_Type,
     &_Py_GenericAliasIterType,
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 24b260d2a3cb83..6874e174460bb3 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8419,6 +8419,64 @@ slot_tp_finalize(PyObject *self)
     PyErr_Restore(error_type, error_value, error_traceback);
 }
 
+typedef struct _PyBufferWrapper {
+    PyObject_HEAD
+    PyObject *mv;
+    PyObject *obj;
+} PyBufferWrapper;
+
+static int
+bufferwrapper_traverse(PyObject *self, visitproc visit, void *arg)
+{
+    PyBufferWrapper *bw = (PyBufferWrapper *)self;
+
+    Py_VISIT(bw->mv);
+    Py_VISIT(bw->obj);
+    return 0;
+}
+
+static void
+bufferwrapper_dealloc(PyObject *self)
+{
+    PyBufferWrapper *bw = (PyBufferWrapper *)self;
+
+    _PyObject_GC_UNTRACK(self);
+    Py_XDECREF(bw->mv);
+    Py_XDECREF(bw->obj);
+    Py_TYPE(self)->tp_free(self);
+}
+
+static void
+bufferwrapper_releasebuf(PyObject *self, Py_buffer *view)
+{
+    PyBufferWrapper *bw = (PyBufferWrapper *)self;
+
+    assert(PyMemoryView_Check(bw->mv));
+    Py_TYPE(bw->mv)->tp_as_buffer->bf_releasebuffer(bw->mv, view);
+    if (Py_TYPE(bw->obj)->tp_as_buffer != NULL 
+        && Py_TYPE(bw->obj)->tp_as_buffer->bf_releasebuffer != NULL) {
+        Py_TYPE(bw->obj)->tp_as_buffer->bf_releasebuffer(bw->obj, view);
+    }
+}
+
+static PyBufferProcs bufferwrapper_as_buffer = {
+    .bf_releasebuffer = bufferwrapper_releasebuf,
+};
+
+
+PyTypeObject _PyBufferWrapper_Type = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    .tp_name = "_buffer_wrapper",
+    .tp_basicsize = sizeof(PyBufferWrapper),
+    .tp_alloc = PyType_GenericAlloc,
+    .tp_new = PyType_GenericNew,
+    .tp_free = PyObject_GC_Del,
+    .tp_traverse = bufferwrapper_traverse,
+    .tp_dealloc = bufferwrapper_dealloc,
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
+    .tp_as_buffer = &bufferwrapper_as_buffer,
+};
+
 static int 
 slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
 {
@@ -8426,6 +8484,7 @@ slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
     if (flags_obj == NULL) {
         return -1;
     }
+    PyObject *wrapper = NULL;
     PyObject *stack[2] = {self, flags_obj};
     PyObject *ret = vectorcall_method(&_Py_ID(__buffer__), stack, 2);
     if (ret == NULL) {
@@ -8436,13 +8495,27 @@ slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
                      "__buffer__ returned non-memoryview object");
         goto fail;
     }
-    *buffer = ((PyMemoryViewObject *)ret)->view;
-    Py_INCREF(buffer->obj);
+
+    if (PyObject_GetBuffer(ret, buffer, flags) < 0) {
+        goto fail;
+    }
+    assert(buffer->obj == ret);
+
+    wrapper = PyObject_GC_New(PyBufferWrapper, &_PyBufferWrapper_Type);
+    if (wrapper == NULL) {
+        goto fail;
+    }
+    ((PyBufferWrapper *)wrapper)->mv = ret;
+    ((PyBufferWrapper *)wrapper)->obj = Py_NewRef(self);
+    _PyObject_GC_TRACK(wrapper);
+
+    buffer->obj = wrapper;
     Py_DECREF(ret);
     Py_DECREF(flags_obj);
     return 0;
 
 fail:
+    Py_XDECREF(wrapper);
     Py_XDECREF(ret);
     Py_DECREF(flags_obj);
     return -1;
@@ -8456,9 +8529,6 @@ slot_bf_releasebuffer(PyObject *self, Py_buffer *buffer)
         PyErr_WriteUnraisable(self);
         return;
     }
-    if (buffer->obj != NULL) {
-        ((PyMemoryViewObject *)mv)->view.obj = Py_NewRef(buffer->obj);
-    }
     PyObject *stack[2] = {self, mv};
     PyObject *ret = vectorcall_method(&_Py_ID(__release_buffer__), stack, 2);
     Py_DECREF(mv);

From ac10887613a1f067487eeb35581ec525f996c190 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 4 Oct 2022 17:01:52 -0700
Subject: [PATCH 05/35] one more test

---
 Lib/test/test_collections.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index a8ea91d973638f..23483c5086d578 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -1948,6 +1948,7 @@ def test_Buffer(self):
         for sample in [str, list, tuple]:
             self.assertNotIsInstance(sample(), Buffer)
             self.assertFalse(issubclass(sample, Buffer))
+        self.validate_abstract_methods(Buffer, '__buffer__')
 
     def test_MutableBuffer(self):
         for sample in [bytearray, memoryview]:
@@ -1956,6 +1957,7 @@ def test_MutableBuffer(self):
         for sample in [bytes, str, list, tuple]:
             self.assertNotIsInstance(sample(), MutableBuffer)
             self.assertFalse(issubclass(sample, MutableBuffer))
+        self.validate_abstract_methods(MutableBuffer, '__buffer__', '__release_buffer__')
 
     def test_MutableSequence(self):
         for sample in [tuple, str, bytes]:

From 530a16099087030a6f3953a86d352cb51f578138 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Wed, 5 Oct 2022 14:17:22 -0700
Subject: [PATCH 06/35] additions

---
 Include/pybuffer.h      |  2 +-
 Lib/inspect.py          | 22 ++++++++++++++++++++++
 Lib/test/test_buffer.py | 23 +++++++++++++++++++++++
 Objects/typeobject.c    | 16 ++++++++++++----
 4 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/Include/pybuffer.h b/Include/pybuffer.h
index 6893505e66e3e8..7173639520fe50 100644
--- a/Include/pybuffer.h
+++ b/Include/pybuffer.h
@@ -101,7 +101,7 @@ PyAPI_FUNC(void) PyBuffer_Release(Py_buffer *view);
 /* Maximum number of dimensions */
 #define PyBUF_MAX_NDIM 64
 
-/* Flags for getting buffers */
+/* Flags for getting buffers. Keep these in sync with inspect.BufferFlags. */
 #define PyBUF_SIMPLE 0
 #define PyBUF_WRITABLE 0x0001
 
diff --git a/Lib/inspect.py b/Lib/inspect.py
index 498ee7ab9eaf8a..f71ae8eb53bd85 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -3273,6 +3273,28 @@ def signature(obj, *, follow_wrapped=True, globals=None, locals=None, eval_str=F
                                    globals=globals, locals=locals, eval_str=eval_str)
 
 
+class BufferFlags(enum.IntFlag):
+    SIMPLE = 0x0
+    WRITABLE = 0x1
+    FORMAT = 0x4
+    ND = 0x8
+    STRIDES = 0x10 | ND
+    C_CONTIGUOUS = 0x20 | STRIDES
+    F_CONTIGUOUS = 0x40 | STRIDES
+    ANY_CONTIGUOUS = 0x80 | STRIDES
+    INDIRECT = 0x100 | STRIDES
+    CONTIG = ND | WRITABLE
+    CONTIG_RO = ND
+    STRIDED = STRIDES | WRITABLE
+    STRIDED_RO = STRIDES
+    RECORDS = STRIDES | WRITABLE | FORMAT
+    RECORDS_RO = STRIDES | FORMAT
+    FULL = INDIRECT | WRITABLE | FORMAT
+    FULL_RO = INDIRECT | FORMAT
+    READ = 0x100
+    WRITE = 0x200
+
+
 def _main():
     """ Logic for inspecting an object given at command line """
     import argparse
diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index c46045ae96485e..9bee30bacd3b73 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4479,6 +4479,29 @@ def __release_buffer__(self, buffer):
             self.assertEqual(mv.tobytes(), b"hello")
         self.assertFalse(wr.held)
 
+    def test_same_buffer_returned(self):
+        class WhatToRelease:
+            def __init__(self):
+                self.held = False
+                self.ba = bytearray(b"hello")
+                self.created_mv = None
+            def __buffer__(self, flags):
+                if self.held:
+                    raise TypeError("already held")
+                self.held = True
+                self.created_mv = memoryview(self.ba)
+                return self.created_mv
+            def __release_buffer__(self, buffer):
+                assert buffer is self.created_mv
+                self.held = False
+
+        wr = WhatToRelease()
+        self.assertFalse(wr.held)
+        with memoryview(wr) as mv:
+            self.assertTrue(wr.held)
+            self.assertEqual(mv.tobytes(), b"hello")
+        self.assertFalse(wr.held)
+
     def test_call_builtins(self):
         ba = bytearray(b"hello")
         mv = ba.__buffer__(0)
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 0bdf5ec69f390c..820fba90801818 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8526,10 +8526,18 @@ slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
 static void
 slot_bf_releasebuffer(PyObject *self, Py_buffer *buffer)
 {
-    PyObject *mv = PyMemoryView_FromBuffer(buffer);
-    if (mv == NULL) {
-        PyErr_WriteUnraisable(self);
-        return;
+    PyObject *mv;
+    if (Py_TYPE(buffer->obj) == &_PyBufferWrapper_Type) {
+        // Make sure we pass the same memoryview to
+        // __release_buffer__() that __buffer__() returned.
+        mv = Py_NewRef(((PyBufferWrapper *)buffer->obj)->mv);
+    }
+    else {
+        mv = PyMemoryView_FromBuffer(buffer);
+        if (mv == NULL) {
+            PyErr_WriteUnraisable(self);
+            return;
+        }
     }
     PyObject *stack[2] = {self, mv};
     PyObject *ret = vectorcall_method(&_Py_ID(__release_buffer__), stack, 2);

From 207d2fd67ebe2bdcf22348cb50e4bfdf0a33a2eb Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 20 Oct 2022 21:46:56 -0700
Subject: [PATCH 07/35] introduce __mutable_buffer__ (rather hackily)

---
 Include/internal/pycore_abstract.h |  4 ++++
 Lib/_collections_abc.py            |  7 ++-----
 Modules/_ctypes/_ctypes.c          | 17 +++++++++++++----
 Modules/_io/bytesio.c              |  8 +++++++-
 Modules/arraymodule.c              |  2 ++
 Modules/mmapmodule.c               |  2 ++
 Objects/abstract.c                 |  5 +++++
 Objects/bytearrayobject.c          |  9 +++++++--
 Objects/memoryobject.c             |  3 ++-
 Objects/picklebufobject.c          |  6 ++++++
 Objects/typeobject.c               | 25 +++++++++++++++++--------
 11 files changed, 67 insertions(+), 21 deletions(-)

diff --git a/Include/internal/pycore_abstract.h b/Include/internal/pycore_abstract.h
index b1afb2dc7be65e..6db26bf246ee7c 100644
--- a/Include/internal/pycore_abstract.h
+++ b/Include/internal/pycore_abstract.h
@@ -19,6 +19,10 @@ _PyIndex_Check(PyObject *obj)
 PyObject *_PyNumber_PowerNoMod(PyObject *lhs, PyObject *rhs);
 PyObject *_PyNumber_InPlacePowerNoMod(PyObject *lhs, PyObject *rhs);
 
+PyAPI_FUNC(PyObject *) _PyBuffer_MutableBufferGetter(PyObject *instance, void *ignored);
+
+#define _PY_BUFFER_MUTABLE_BUFFER_GETSET { "__mutable_buffer__", _PyBuffer_MutableBufferGetter, NULL, NULL },
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py
index 3b0d0eeb1fa9d1..c4b3e687315658 100644
--- a/Lib/_collections_abc.py
+++ b/Lib/_collections_abc.py
@@ -457,15 +457,12 @@ def __subclasshook__(cls, C):
 class MutableBuffer(Buffer):
 
     __slots__ = ()
-
-    @abstractmethod
-    def __release_buffer__(self, buffer: memoryview, /) -> None:
-        pass
+    __mutable_buffer__ = True
 
     @classmethod
     def __subclasshook__(cls, C):
         if cls is MutableBuffer:
-            return _check_methods(C, "__buffer__", "__release_buffer__")
+            return _check_methods(C, "__buffer__", "__mutable_buffer__")
         return NotImplemented
 
 
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index a3c7c8c471e584..1dbd85423bb87f 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -127,6 +127,7 @@ bytes(cdata)
 #include "ctypes.h"
 
 #include "pycore_long.h"          // _PyLong_GetZero()
+#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 
 PyObject *PyExc_ArgError = NULL;
 
@@ -2809,6 +2810,11 @@ static PyBufferProcs PyCData_as_buffer = {
     NULL,
 };
 
+static PyGetSetDef PyCData_getset[] = {
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
+    {NULL}
+};
+
 /*
  * CData objects are mutable, so they cannot be hashable!
  */
@@ -2918,7 +2924,7 @@ PyTypeObject PyCData_Type = {
     0,                                          /* tp_iternext */
     PyCData_methods,                                    /* tp_methods */
     PyCData_members,                                    /* tp_members */
-    0,                                          /* tp_getset */
+    PyCData_getset,                             /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     0,                                          /* tp_descr_get */
@@ -3342,6 +3348,7 @@ static PyGetSetDef PyCFuncPtr_getsets[] = {
     { "argtypes", (getter)PyCFuncPtr_get_argtypes,
       (setter)PyCFuncPtr_set_argtypes,
       "specify the argument types", NULL },
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     { NULL, NULL }
 };
 
@@ -4468,7 +4475,7 @@ static PyTypeObject Struct_Type = {
     0,                                          /* tp_iternext */
     0,                                          /* tp_methods */
     0,                                          /* tp_members */
-    0,                                          /* tp_getset */
+    PyCData_getset,                             /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     0,                                          /* tp_descr_get */
@@ -4510,7 +4517,7 @@ static PyTypeObject Union_Type = {
     0,                                          /* tp_iternext */
     0,                                          /* tp_methods */
     0,                                          /* tp_members */
-    0,                                          /* tp_getset */
+    PyCData_getset,                             /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     0,                                          /* tp_descr_get */
@@ -4830,7 +4837,7 @@ PyTypeObject PyCArray_Type = {
     0,                                          /* tp_iternext */
     Array_methods,                              /* tp_methods */
     0,                                          /* tp_members */
-    0,                                          /* tp_getset */
+    PyCData_getset,                             /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     0,                                          /* tp_descr_get */
@@ -4961,6 +4968,7 @@ Simple_get_value(CDataObject *self, void *Py_UNUSED(ignored))
 static PyGetSetDef Simple_getsets[] = {
     { "value", (getter)Simple_get_value, (setter)Simple_set_value,
       "current value", NULL },
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     { NULL, NULL }
 };
 
@@ -5204,6 +5212,7 @@ static PyGetSetDef Pointer_getsets[] = {
     { "contents", (getter)Pointer_get_contents,
       (setter)Pointer_set_contents,
       "the object this pointer points to (read-write)", NULL },
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     { NULL, NULL }
 };
 
diff --git a/Modules/_io/bytesio.c b/Modules/_io/bytesio.c
index 930ef7e29dbcf6..20e3e6a0ef7435 100644
--- a/Modules/_io/bytesio.c
+++ b/Modules/_io/bytesio.c
@@ -1,4 +1,5 @@
 #include "Python.h"
+#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include "pycore_object.h"
 #include <stddef.h>               // offsetof()
 #include "_iomodule.h"
@@ -1124,6 +1125,11 @@ static PyBufferProcs bytesiobuf_as_buffer = {
     (releasebufferproc) bytesiobuf_releasebuffer,
 };
 
+static PyGetSetDef bytesiobuf_getset[] = {
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
+    {NULL}
+};
+
 Py_EXPORTED_SYMBOL PyTypeObject _PyBytesIOBuffer_Type = {
     PyVarObject_HEAD_INIT(NULL, 0)
     "_io._BytesIOBuffer",                      /*tp_name*/
@@ -1154,7 +1160,7 @@ Py_EXPORTED_SYMBOL PyTypeObject _PyBytesIOBuffer_Type = {
     0,                                         /*tp_iternext*/
     0,                                         /*tp_methods*/
     0,                                         /*tp_members*/
-    0,                                         /*tp_getset*/
+    bytesiobuf_getset,                         /*tp_getset*/
     0,                                         /*tp_base*/
     0,                                         /*tp_dict*/
     0,                                         /*tp_descr_get*/
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 924fbf29bfb889..98c28124909d50 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -9,6 +9,7 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
+#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include "pycore_moduleobject.h"  // _PyModule_GetState()
 #include "pycore_bytesobject.h"   // _PyBytes_Repeat
 #include "structmember.h"         // PyMemberDef
@@ -2277,6 +2278,7 @@ static PyGetSetDef array_getsets [] = {
      "the typecode character used to create the array"},
     {"itemsize", (getter) array_get_itemsize, NULL,
      "the size, in bytes, of one array item"},
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     {NULL}
 };
 
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index fdce783fdec5e2..85cb0a524fb227 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -24,6 +24,7 @@
 
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
+#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include "pycore_bytesobject.h"   // _PyBytes_Find()
 #include "pycore_fileutils.h"     // _Py_stat_struct
 #include "structmember.h"         // PyMemberDef
@@ -887,6 +888,7 @@ static struct PyMethodDef mmap_object_methods[] = {
 
 static PyGetSetDef mmap_object_getset[] = {
     {"closed", (getter) mmap_closed_get, NULL, NULL},
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     {NULL}
 };
 
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 5d50491b2dd347..ea40cbe30ba1b4 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2967,3 +2967,8 @@ _Py_FreeCharPArray(char *const array[])
     }
     PyMem_Free((void*)array);
 }
+
+PyObject *
+_PyBuffer_MutableBufferGetter(PyObject *instance, void *ignored) {
+    Py_RETURN_TRUE;
+}
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index b2962fd137d93e..a413deba623dab 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -2,7 +2,7 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
-#include "pycore_abstract.h"      // _PyIndex_Check()
+#include "pycore_abstract.h"      // _PyIndex_Check(), _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include "pycore_bytes_methods.h"
 #include "pycore_bytesobject.h"
 #include "pycore_object.h"        // _PyObject_GC_UNTRACK()
@@ -2289,6 +2289,11 @@ Construct a mutable bytearray object from:\n\
 
 static PyObject *bytearray_iter(PyObject *seq);
 
+static PyGetSetDef bytearray_getset[] = {
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
+    {NULL}
+};
+
 PyTypeObject PyByteArray_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "bytearray",
@@ -2320,7 +2325,7 @@ PyTypeObject PyByteArray_Type = {
     0,                                  /* tp_iternext */
     bytearray_methods,                  /* tp_methods */
     0,                                  /* tp_members */
-    0,                                  /* tp_getset */
+    bytearray_getset,                   /* tp_getset */
     0,                                  /* tp_base */
     0,                                  /* tp_dict */
     0,                                  /* tp_descr_get */
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index db832aa5c9b22a..6e414ee5f52427 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -11,7 +11,7 @@
  */
 
 #include "Python.h"
-#include "pycore_abstract.h"      // _PyIndex_Check()
+#include "pycore_abstract.h"      // _PyIndex_Check(), _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include "pycore_object.h"        // _PyObject_GC_UNTRACK()
 #include "pycore_strhex.h"        // _Py_strhex_with_sep()
 #include <stddef.h>               // offsetof()
@@ -3186,6 +3186,7 @@ static PyGetSetDef memory_getsetlist[] = {
     {"c_contiguous",    (getter)memory_c_contiguous,   NULL, memory_c_contiguous_doc},
     {"f_contiguous",    (getter)memory_f_contiguous,   NULL, memory_f_contiguous_doc},
     {"contiguous",      (getter)memory_contiguous,     NULL, memory_contiguous_doc},
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     {NULL, NULL, NULL, NULL},
 };
 
diff --git a/Objects/picklebufobject.c b/Objects/picklebufobject.c
index aaa852cfbb05b0..7ec04206fa47df 100644
--- a/Objects/picklebufobject.c
+++ b/Objects/picklebufobject.c
@@ -2,6 +2,7 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
+#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include <stddef.h>
 
 typedef struct {
@@ -203,6 +204,10 @@ static PyMethodDef picklebuf_methods[] = {
     {NULL,      NULL}
 };
 
+static PyGetSetDef picklebuf_getset[] = {
+    _PY_BUFFER_MUTABLE_BUFFER_GETSET
+    {NULL}
+};
 PyTypeObject PyPickleBuffer_Type = {
     PyVarObject_HEAD_INIT(NULL, 0)
     .tp_name = "pickle.PickleBuffer",
@@ -216,4 +221,5 @@ PyTypeObject PyPickleBuffer_Type = {
     .tp_weaklistoffset = offsetof(PyPickleBufferObject, weakreflist),
     .tp_as_buffer = &picklebuf_as_buffer,
     .tp_methods = picklebuf_methods,
+    .tp_getset = picklebuf_getset,
 };
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 820fba90801818..0d979a1375cec6 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2,6 +2,7 @@
 
 #include "Python.h"
 #include "pycore_call.h"
+#include "pycore_abstract.h"      // _PyBuffer_MutableBufferGetter
 #include "pycore_code.h"          // CO_FAST_FREE
 #include "pycore_compile.h"       // _Py_Mangle()
 #include "pycore_initconfig.h"    // _PyStatus_OK()
@@ -6094,16 +6095,24 @@ type_add_getset(PyTypeObject *type)
 
     PyObject *dict = type->tp_dict;
     for (; gsp->name != NULL; gsp++) {
-        PyObject *descr = PyDescr_NewGetSet(type, gsp);
-        if (descr == NULL) {
-            return -1;
-        }
-
-        if (PyDict_SetDefault(dict, PyDescr_NAME(descr), descr) == NULL) {
+        if (gsp->get == _PyBuffer_MutableBufferGetter) {
+            PyObject *name = PyUnicode_FromString(gsp->name);
+            if (PyDict_SetDefault(dict, name, Py_True) == NULL) {
+                Py_DECREF(name);
+                return -1;
+            }
+            Py_DECREF(name);
+        } else {
+            PyObject *descr = PyDescr_NewGetSet(type, gsp);
+            if (descr == NULL) {
+                return -1;
+            }
+            if (PyDict_SetDefault(dict, PyDescr_NAME(descr), descr) == NULL) {
+                Py_DECREF(descr);
+                return -1;
+            }
             Py_DECREF(descr);
-            return -1;
         }
-        Py_DECREF(descr);
     }
     return 0;
 }

From 007fdc115383b42b78ddf28bdcd47714de9c53e7 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Sun, 6 Nov 2022 06:47:23 -0800
Subject: [PATCH 08/35] Rip out __mutable_buffer__

---
 Include/internal/pycore_abstract.h |  4 ----
 Lib/_collections_abc.py            | 14 +-------------
 Lib/test/test_collections.py       | 11 +----------
 Modules/_ctypes/_ctypes.c          | 17 ++++-------------
 Modules/_io/bytesio.c              |  8 +-------
 Modules/arraymodule.c              |  2 --
 Modules/mmapmodule.c               |  2 --
 Objects/abstract.c                 |  5 -----
 Objects/bytearrayobject.c          |  9 ++-------
 Objects/memoryobject.c             |  3 +--
 Objects/picklebufobject.c          |  6 ------
 Objects/typeobject.c               | 30 ++++++++++--------------------
 12 files changed, 20 insertions(+), 91 deletions(-)

diff --git a/Include/internal/pycore_abstract.h b/Include/internal/pycore_abstract.h
index 6db26bf246ee7c..b1afb2dc7be65e 100644
--- a/Include/internal/pycore_abstract.h
+++ b/Include/internal/pycore_abstract.h
@@ -19,10 +19,6 @@ _PyIndex_Check(PyObject *obj)
 PyObject *_PyNumber_PowerNoMod(PyObject *lhs, PyObject *rhs);
 PyObject *_PyNumber_InPlacePowerNoMod(PyObject *lhs, PyObject *rhs);
 
-PyAPI_FUNC(PyObject *) _PyBuffer_MutableBufferGetter(PyObject *instance, void *ignored);
-
-#define _PY_BUFFER_MUTABLE_BUFFER_GETSET { "__mutable_buffer__", _PyBuffer_MutableBufferGetter, NULL, NULL },
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/Lib/_collections_abc.py b/Lib/_collections_abc.py
index c4b3e687315658..10ddcaf3e00134 100644
--- a/Lib/_collections_abc.py
+++ b/Lib/_collections_abc.py
@@ -49,7 +49,7 @@ def _f(): pass
            "Mapping", "MutableMapping",
            "MappingView", "KeysView", "ItemsView", "ValuesView",
            "Sequence", "MutableSequence",
-           "ByteString", "Buffer", "MutableBuffer",
+           "ByteString", "Buffer",
            ]
 
 # This module has been renamed from collections.abc to _collections_abc to
@@ -454,18 +454,6 @@ def __subclasshook__(cls, C):
         return NotImplemented
 
 
-class MutableBuffer(Buffer):
-
-    __slots__ = ()
-    __mutable_buffer__ = True
-
-    @classmethod
-    def __subclasshook__(cls, C):
-        if cls is MutableBuffer:
-            return _check_methods(C, "__buffer__", "__mutable_buffer__")
-        return NotImplemented
-
-
 class _CallableGenericAlias(GenericAlias):
     """ Represent `Callable[argtypes, resulttype]`.
 
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index e1b6f2bafe0930..b257b66fcf6752 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -25,7 +25,7 @@
 from collections.abc import Set, MutableSet
 from collections.abc import Mapping, MutableMapping, KeysView, ItemsView, ValuesView
 from collections.abc import Sequence, MutableSequence
-from collections.abc import ByteString, Buffer, MutableBuffer
+from collections.abc import ByteString, Buffer
 
 
 class TestUserObjects(unittest.TestCase):
@@ -1953,15 +1953,6 @@ def test_Buffer(self):
             self.assertFalse(issubclass(sample, Buffer))
         self.validate_abstract_methods(Buffer, '__buffer__')
 
-    def test_MutableBuffer(self):
-        for sample in [bytearray, memoryview]:
-            self.assertIsInstance(sample(b"x"), MutableBuffer)
-            self.assertTrue(issubclass(sample, MutableBuffer))
-        for sample in [bytes, str, list, tuple]:
-            self.assertNotIsInstance(sample(), MutableBuffer)
-            self.assertFalse(issubclass(sample, MutableBuffer))
-        self.validate_abstract_methods(MutableBuffer, '__buffer__', '__release_buffer__')
-
     def test_MutableSequence(self):
         for sample in [tuple, str, bytes]:
             self.assertNotIsInstance(sample(), MutableSequence)
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index 0e89ca0e079274..f342b17abca698 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -125,7 +125,6 @@ bytes(cdata)
 #include "ctypes.h"
 
 #include "pycore_long.h"          // _PyLong_GetZero()
-#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 
 PyObject *PyExc_ArgError = NULL;
 
@@ -2793,11 +2792,6 @@ static PyBufferProcs PyCData_as_buffer = {
     NULL,
 };
 
-static PyGetSetDef PyCData_getset[] = {
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
-    {NULL}
-};
-
 /*
  * CData objects are mutable, so they cannot be hashable!
  */
@@ -2907,7 +2901,7 @@ PyTypeObject PyCData_Type = {
     0,                                          /* tp_iternext */
     PyCData_methods,                                    /* tp_methods */
     PyCData_members,                                    /* tp_members */
-    PyCData_getset,                             /* tp_getset */
+    0,                                          /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     0,                                          /* tp_descr_get */
@@ -3330,7 +3324,6 @@ static PyGetSetDef PyCFuncPtr_getsets[] = {
     { "argtypes", (getter)PyCFuncPtr_get_argtypes,
       (setter)PyCFuncPtr_set_argtypes,
       "specify the argument types", NULL },
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     { NULL, NULL }
 };
 
@@ -4455,7 +4448,7 @@ static PyTypeObject Struct_Type = {
     0,                                          /* tp_iternext */
     0,                                          /* tp_methods */
     0,                                          /* tp_members */
-    PyCData_getset,                             /* tp_getset */
+    0,                                          /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     0,                                          /* tp_descr_get */
@@ -4497,7 +4490,7 @@ static PyTypeObject Union_Type = {
     0,                                          /* tp_iternext */
     0,                                          /* tp_methods */
     0,                                          /* tp_members */
-    PyCData_getset,                             /* tp_getset */
+    0,                                          /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     0,                                          /* tp_descr_get */
@@ -4817,7 +4810,7 @@ PyTypeObject PyCArray_Type = {
     0,                                          /* tp_iternext */
     Array_methods,                              /* tp_methods */
     0,                                          /* tp_members */
-    PyCData_getset,                             /* tp_getset */
+    0,                                          /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     0,                                          /* tp_descr_get */
@@ -4948,7 +4941,6 @@ Simple_get_value(CDataObject *self, void *Py_UNUSED(ignored))
 static PyGetSetDef Simple_getsets[] = {
     { "value", (getter)Simple_get_value, (setter)Simple_set_value,
       "current value", NULL },
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     { NULL, NULL }
 };
 
@@ -5192,7 +5184,6 @@ static PyGetSetDef Pointer_getsets[] = {
     { "contents", (getter)Pointer_get_contents,
       (setter)Pointer_set_contents,
       "the object this pointer points to (read-write)", NULL },
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     { NULL, NULL }
 };
 
diff --git a/Modules/_io/bytesio.c b/Modules/_io/bytesio.c
index 20e3e6a0ef7435..930ef7e29dbcf6 100644
--- a/Modules/_io/bytesio.c
+++ b/Modules/_io/bytesio.c
@@ -1,5 +1,4 @@
 #include "Python.h"
-#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include "pycore_object.h"
 #include <stddef.h>               // offsetof()
 #include "_iomodule.h"
@@ -1125,11 +1124,6 @@ static PyBufferProcs bytesiobuf_as_buffer = {
     (releasebufferproc) bytesiobuf_releasebuffer,
 };
 
-static PyGetSetDef bytesiobuf_getset[] = {
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
-    {NULL}
-};
-
 Py_EXPORTED_SYMBOL PyTypeObject _PyBytesIOBuffer_Type = {
     PyVarObject_HEAD_INIT(NULL, 0)
     "_io._BytesIOBuffer",                      /*tp_name*/
@@ -1160,7 +1154,7 @@ Py_EXPORTED_SYMBOL PyTypeObject _PyBytesIOBuffer_Type = {
     0,                                         /*tp_iternext*/
     0,                                         /*tp_methods*/
     0,                                         /*tp_members*/
-    bytesiobuf_getset,                         /*tp_getset*/
+    0,                                         /*tp_getset*/
     0,                                         /*tp_base*/
     0,                                         /*tp_dict*/
     0,                                         /*tp_descr_get*/
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index ab690efd52dd9f..d60cf26788f5a6 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -9,7 +9,6 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
-#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include "pycore_moduleobject.h"  // _PyModule_GetState()
 #include "pycore_bytesobject.h"   // _PyBytes_Repeat
 #include "structmember.h"         // PyMemberDef
@@ -2278,7 +2277,6 @@ static PyGetSetDef array_getsets [] = {
      "the typecode character used to create the array"},
     {"itemsize", (getter) array_get_itemsize, NULL,
      "the size, in bytes, of one array item"},
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     {NULL}
 };
 
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 85cb0a524fb227..fdce783fdec5e2 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -24,7 +24,6 @@
 
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
-#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include "pycore_bytesobject.h"   // _PyBytes_Find()
 #include "pycore_fileutils.h"     // _Py_stat_struct
 #include "structmember.h"         // PyMemberDef
@@ -888,7 +887,6 @@ static struct PyMethodDef mmap_object_methods[] = {
 
 static PyGetSetDef mmap_object_getset[] = {
     {"closed", (getter) mmap_closed_get, NULL, NULL},
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     {NULL}
 };
 
diff --git a/Objects/abstract.c b/Objects/abstract.c
index ea40cbe30ba1b4..5d50491b2dd347 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2967,8 +2967,3 @@ _Py_FreeCharPArray(char *const array[])
     }
     PyMem_Free((void*)array);
 }
-
-PyObject *
-_PyBuffer_MutableBufferGetter(PyObject *instance, void *ignored) {
-    Py_RETURN_TRUE;
-}
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index a413deba623dab..b2962fd137d93e 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -2,7 +2,7 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
-#include "pycore_abstract.h"      // _PyIndex_Check(), _PY_BUFFER_MUTABLE_BUFFER_GETSET
+#include "pycore_abstract.h"      // _PyIndex_Check()
 #include "pycore_bytes_methods.h"
 #include "pycore_bytesobject.h"
 #include "pycore_object.h"        // _PyObject_GC_UNTRACK()
@@ -2289,11 +2289,6 @@ Construct a mutable bytearray object from:\n\
 
 static PyObject *bytearray_iter(PyObject *seq);
 
-static PyGetSetDef bytearray_getset[] = {
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
-    {NULL}
-};
-
 PyTypeObject PyByteArray_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "bytearray",
@@ -2325,7 +2320,7 @@ PyTypeObject PyByteArray_Type = {
     0,                                  /* tp_iternext */
     bytearray_methods,                  /* tp_methods */
     0,                                  /* tp_members */
-    bytearray_getset,                   /* tp_getset */
+    0,                                  /* tp_getset */
     0,                                  /* tp_base */
     0,                                  /* tp_dict */
     0,                                  /* tp_descr_get */
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index 6e414ee5f52427..db832aa5c9b22a 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -11,7 +11,7 @@
  */
 
 #include "Python.h"
-#include "pycore_abstract.h"      // _PyIndex_Check(), _PY_BUFFER_MUTABLE_BUFFER_GETSET
+#include "pycore_abstract.h"      // _PyIndex_Check()
 #include "pycore_object.h"        // _PyObject_GC_UNTRACK()
 #include "pycore_strhex.h"        // _Py_strhex_with_sep()
 #include <stddef.h>               // offsetof()
@@ -3186,7 +3186,6 @@ static PyGetSetDef memory_getsetlist[] = {
     {"c_contiguous",    (getter)memory_c_contiguous,   NULL, memory_c_contiguous_doc},
     {"f_contiguous",    (getter)memory_f_contiguous,   NULL, memory_f_contiguous_doc},
     {"contiguous",      (getter)memory_contiguous,     NULL, memory_contiguous_doc},
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
     {NULL, NULL, NULL, NULL},
 };
 
diff --git a/Objects/picklebufobject.c b/Objects/picklebufobject.c
index 7ec04206fa47df..aaa852cfbb05b0 100644
--- a/Objects/picklebufobject.c
+++ b/Objects/picklebufobject.c
@@ -2,7 +2,6 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
-#include "pycore_abstract.h"      // _PY_BUFFER_MUTABLE_BUFFER_GETSET
 #include <stddef.h>
 
 typedef struct {
@@ -204,10 +203,6 @@ static PyMethodDef picklebuf_methods[] = {
     {NULL,      NULL}
 };
 
-static PyGetSetDef picklebuf_getset[] = {
-    _PY_BUFFER_MUTABLE_BUFFER_GETSET
-    {NULL}
-};
 PyTypeObject PyPickleBuffer_Type = {
     PyVarObject_HEAD_INIT(NULL, 0)
     .tp_name = "pickle.PickleBuffer",
@@ -221,5 +216,4 @@ PyTypeObject PyPickleBuffer_Type = {
     .tp_weaklistoffset = offsetof(PyPickleBufferObject, weakreflist),
     .tp_as_buffer = &picklebuf_as_buffer,
     .tp_methods = picklebuf_methods,
-    .tp_getset = picklebuf_getset,
 };
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 9e3b6d81dddaac..18ffd3f26af77b 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2,7 +2,6 @@
 
 #include "Python.h"
 #include "pycore_call.h"
-#include "pycore_abstract.h"      // _PyBuffer_MutableBufferGetter
 #include "pycore_code.h"          // CO_FAST_FREE
 #include "pycore_compile.h"       // _Py_Mangle()
 #include "pycore_initconfig.h"    // _PyStatus_OK()
@@ -6196,24 +6195,15 @@ type_add_getset(PyTypeObject *type)
 
     PyObject *dict = type->tp_dict;
     for (; gsp->name != NULL; gsp++) {
-        if (gsp->get == _PyBuffer_MutableBufferGetter) {
-            PyObject *name = PyUnicode_FromString(gsp->name);
-            if (PyDict_SetDefault(dict, name, Py_True) == NULL) {
-                Py_DECREF(name);
-                return -1;
-            }
-            Py_DECREF(name);
-        } else {
-            PyObject *descr = PyDescr_NewGetSet(type, gsp);
-            if (descr == NULL) {
-                return -1;
-            }
-            if (PyDict_SetDefault(dict, PyDescr_NAME(descr), descr) == NULL) {
-                Py_DECREF(descr);
-                return -1;
-            }
+        PyObject *descr = PyDescr_NewGetSet(type, gsp);
+        if (descr == NULL) {
+            return -1;
+        }
+        if (PyDict_SetDefault(dict, PyDescr_NAME(descr), descr) == NULL) {
             Py_DECREF(descr);
+            return -1;
         }
+        Py_DECREF(descr);
     }
     return 0;
 }
@@ -8565,7 +8555,7 @@ bufferwrapper_releasebuf(PyObject *self, Py_buffer *view)
 
     assert(PyMemoryView_Check(bw->mv));
     Py_TYPE(bw->mv)->tp_as_buffer->bf_releasebuffer(bw->mv, view);
-    if (Py_TYPE(bw->obj)->tp_as_buffer != NULL 
+    if (Py_TYPE(bw->obj)->tp_as_buffer != NULL
         && Py_TYPE(bw->obj)->tp_as_buffer->bf_releasebuffer != NULL) {
         Py_TYPE(bw->obj)->tp_as_buffer->bf_releasebuffer(bw->obj, view);
     }
@@ -8589,7 +8579,7 @@ PyTypeObject _PyBufferWrapper_Type = {
     .tp_as_buffer = &bufferwrapper_as_buffer,
 };
 
-static int 
+static int
 slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
 {
     PyObject *flags_obj = PyLong_FromLong(flags);
@@ -8837,7 +8827,7 @@ static slotdef slotdefs[] = {
             "Return a buffer object that exposes the underlying memory of the object."),
     BUFSLOT(__release_buffer__, bf_releasebuffer, slot_bf_releasebuffer, wrap_releasebuffer,
             "__release_buffer__($self, /)\n--\n\n"
-            "Release the buffer object that exposes the underlying memory of the object."), 
+            "Release the buffer object that exposes the underlying memory of the object."),
 
     AMSLOT(__await__, am_await, slot_am_await, wrap_unaryfunc,
            "__await__($self, /)\n--\n\nReturn an iterator to be used in await expression."),

From 46a9239265c62ac07bdc8127ad74995d0720d161 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Mon, 7 Nov 2022 20:14:38 -0800
Subject: [PATCH 09/35] __release_buffer__ calls mv.release()

---
 Objects/typeobject.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 18ffd3f26af77b..8daa92bf327cfc 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -7685,7 +7685,16 @@ wrap_releasebuffer(PyObject *self, PyObject *args, void *wrapped)
                         "memoryview's buffer is not this object");
         return NULL;
     }
-    (*func)(self, &mview->view);
+    PyObject *release = PyUnicode_FromString("release");
+    if (release == NULL) {
+        return NULL;
+    }
+    PyObject *res = PyObject_CallMethodNoArgs((PyObject *)mview, release);
+    Py_DECREF(release);
+    if (res == NULL) {
+        return NULL;
+    }
+    Py_DECREF(res);
     Py_RETURN_NONE;
 }
 

From be9bf456fb82dd9d15870a33ae0de23c04b4fb52 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Mon, 7 Nov 2022 20:51:53 -0800
Subject: [PATCH 10/35] additional test

---
 Lib/test/test_buffer.py   | 16 ++++++++
 Modules/_testcapimodule.c | 86 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index 9bee30bacd3b73..3e48cf48b791d3 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4508,6 +4508,22 @@ def test_call_builtins(self):
         self.assertEqual(mv.tobytes(), b"hello")
         ba.__release_buffer__(mv)
 
+    @unittest.skipIf(_testcapi is None, "requires _testcapi")
+    def test_c_buffer(self):
+        buf = _testcapi.testBuf()
+        self.assertEqual(buf.references, 0)
+        mv = buf.__buffer__(0)
+        self.assertIsInstance(mv, memoryview)
+        self.assertEqual(mv.tobytes(), b"test")
+        self.assertEqual(buf.references, 1)
+        buf.__release_buffer__(mv)
+        self.assertEqual(buf.references, 0)
+        with self.assertRaises(ValueError):
+            mv.tobytes()
+        # Calling it again doesn't cause issues
+        buf.__release_buffer__(mv)
+        self.assertEqual(buf.references, 0)
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 0e09c97bea09a5..d61b6649118337 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -6804,6 +6804,85 @@ static PyTypeObject MyList_Type = {
     MyList_new,                                 /* tp_new */
 };
 
+typedef struct {
+    PyObject_HEAD
+    PyObject *obj;
+    long references;
+} testBufObject;
+
+static PyObject *
+testbuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+    testBufObject *self = (testBufObject *)type->tp_alloc(type, 0);
+    if (self == NULL) {
+        return NULL;
+    }
+    self->obj = PyBytes_FromString("test");
+    self->references = 0;
+    return (PyObject *)self;
+}
+
+static int
+testbuf_traverse(testBufObject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->obj);
+    return 0;
+}
+
+static int
+testbuf_clear(testBufObject *self)
+{
+    Py_CLEAR(self->obj);
+    return 0;
+}
+
+static void
+testbuf_dealloc(testBufObject *self)
+{
+    PyObject_GC_UnTrack(self);
+    Py_XDECREF(self->obj);
+    Py_TYPE(self)->tp_free((PyObject *) self);
+}
+
+static int
+testbuf_getbuf(testBufObject *self, Py_buffer *view, int flags)
+{
+    int buf = PyObject_GetBuffer(self->obj, view, flags);
+    Py_SETREF(view->obj, Py_NewRef((PyObject *)self));
+    self->references++;
+    return buf;
+}
+
+static void
+testbuf_releasebuf(testBufObject *self, Py_buffer *view)
+{
+    self->references--;
+    assert(self->references >= 0);
+}
+
+static PyBufferProcs testbuf_as_buffer = {
+    .bf_getbuffer = (getbufferproc) testbuf_getbuf,
+    .bf_releasebuffer = (releasebufferproc) testbuf_releasebuf,
+};
+
+static struct PyMemberDef testbuf_members[] = {
+    {"references", T_LONG, offsetof(testBufObject, references), READONLY},
+    {NULL},
+};
+
+static PyTypeObject testBufType = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    .tp_name = "testBufType",
+    .tp_basicsize = sizeof(testBufObject),
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
+    .tp_new = testbuf_new,
+    .tp_dealloc = (destructor) testbuf_dealloc,
+    .tp_traverse = (traverseproc) testbuf_traverse,
+    .tp_clear = (inquiry) testbuf_clear,
+    .tp_as_buffer = &testbuf_as_buffer,
+    .tp_members = testbuf_members
+};
+
 
 /* Test PEP 560 */
 
@@ -7042,6 +7121,13 @@ PyInit__testcapi(void)
     Py_INCREF(&MyList_Type);
     PyModule_AddObject(m, "MyList", (PyObject *)&MyList_Type);
 
+    if (PyType_Ready(&testBufType) < 0) {
+        return NULL;
+    }
+    if (PyModule_AddObjectRef(m, "testBuf", (PyObject *)&testBufType)) {
+        return NULL;
+    }
+
     if (PyType_Ready(&GenericAlias_Type) < 0)
         return NULL;
     Py_INCREF(&GenericAlias_Type);

From a6bf0e81c7cd6b6e086ba98c07f3baefc3cb6f9f Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Mon, 7 Nov 2022 20:58:28 -0800
Subject: [PATCH 11/35] undo stray change

---
 Objects/typeobject.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 8daa92bf327cfc..b0cf8fb814a245 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -6199,6 +6199,7 @@ type_add_getset(PyTypeObject *type)
         if (descr == NULL) {
             return -1;
         }
+
         if (PyDict_SetDefault(dict, PyDescr_NAME(descr), descr) == NULL) {
             Py_DECREF(descr);
             return -1;

From 04d0a420fabebc893cecf12abcb8245980ab1e4d Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Sat, 17 Dec 2022 20:37:36 -0800
Subject: [PATCH 12/35] throw an error if already released

---
 Include/internal/pycore_global_objects_fini_generated.h | 2 ++
 Include/internal/pycore_unicodeobject_generated.h       | 4 ++++
 Lib/test/test_buffer.py                                 | 3 ++-
 Objects/typeobject.c                                    | 6 +++++-
 4 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/Include/internal/pycore_global_objects_fini_generated.h b/Include/internal/pycore_global_objects_fini_generated.h
index 6aba2f19ebde4a..e9968a07ade0e8 100644
--- a/Include/internal/pycore_global_objects_fini_generated.h
+++ b/Include/internal/pycore_global_objects_fini_generated.h
@@ -594,6 +594,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__await__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__bases__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__bool__));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__buffer__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__build_class__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__builtins__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__bytes__));
@@ -693,6 +694,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__rdivmod__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__reduce__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__reduce_ex__));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__release_buffer__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__repr__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__reversed__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__rfloordiv__));
diff --git a/Include/internal/pycore_unicodeobject_generated.h b/Include/internal/pycore_unicodeobject_generated.h
index 7f407c0141b8a5..bd1e7196b964ac 100644
--- a/Include/internal/pycore_unicodeobject_generated.h
+++ b/Include/internal/pycore_unicodeobject_generated.h
@@ -66,6 +66,8 @@ _PyUnicode_InitStaticStrings(void) {
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__bool__);
     PyUnicode_InternInPlace(&string);
+    string = &_Py_ID(__buffer__);
+    PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__build_class__);
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__builtins__);
@@ -264,6 +266,8 @@ _PyUnicode_InitStaticStrings(void) {
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__reduce_ex__);
     PyUnicode_InternInPlace(&string);
+    string = &_Py_ID(__release_buffer__);
+    PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__repr__);
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(__reversed__);
diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index 3e48cf48b791d3..8b2d7e12fce17b 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4521,7 +4521,8 @@ def test_c_buffer(self):
         with self.assertRaises(ValueError):
             mv.tobytes()
         # Calling it again doesn't cause issues
-        buf.__release_buffer__(mv)
+        with self.assertRaises(ValueError):
+            buf.__release_buffer__(mv)
         self.assertEqual(buf.references, 0)
 
 
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 95a740c94c9858..7f24503f6f714c 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -7624,7 +7624,6 @@ wrap_buffer(PyObject *self, PyObject *args, void *wrapped)
 static PyObject *
 wrap_releasebuffer(PyObject *self, PyObject *args, void *wrapped)
 {
-    releasebufferproc func = (releasebufferproc)wrapped;
     PyMemoryViewObject *mview;
 
     if (!check_num_args(args, 1)) {
@@ -7638,6 +7637,11 @@ wrap_releasebuffer(PyObject *self, PyObject *args, void *wrapped)
                         "memoryview's buffer is not this object");
         return NULL;
     }
+    if (mview->flags & _Py_MEMORYVIEW_RELEASED) {
+        PyErr_SetString(PyExc_ValueError,
+                        "memoryview's buffer has already been released");
+        return NULL;
+    }
     PyObject *release = PyUnicode_FromString("release");
     if (release == NULL) {
         return NULL;

From 5f755fec0da074bf881c6deb7ea4af71e86cef0f Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 7 Mar 2023 17:35:00 -0800
Subject: [PATCH 13/35] Fix compiler warning

---
 Objects/typeobject.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index f09b3acbc39d35..96282cb2bad905 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8579,7 +8579,7 @@ slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
     if (flags_obj == NULL) {
         return -1;
     }
-    PyObject *wrapper = NULL;
+    PyBufferWrapper *wrapper = NULL;
     PyObject *stack[2] = {self, flags_obj};
     PyObject *ret = vectorcall_method(&_Py_ID(__buffer__), stack, 2);
     if (ret == NULL) {
@@ -8600,11 +8600,11 @@ slot_bf_getbuffer(PyObject *self, Py_buffer *buffer, int flags)
     if (wrapper == NULL) {
         goto fail;
     }
-    ((PyBufferWrapper *)wrapper)->mv = ret;
-    ((PyBufferWrapper *)wrapper)->obj = Py_NewRef(self);
+    wrapper->mv = ret;
+    wrapper->obj = Py_NewRef(self);
     _PyObject_GC_TRACK(wrapper);
 
-    buffer->obj = wrapper;
+    buffer->obj = (PyObject *)wrapper;
     Py_DECREF(ret);
     Py_DECREF(flags_obj);
     return 0;

From 0b02e63d23961ab1f67093415cb35ef34f8a82e8 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 7 Mar 2023 17:37:06 -0800
Subject: [PATCH 14/35] news

---
 .../2023-03-07-17-37-00.gh-issue-102500.RUSQhz.rst             | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2023-03-07-17-37-00.gh-issue-102500.RUSQhz.rst

diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-03-07-17-37-00.gh-issue-102500.RUSQhz.rst b/Misc/NEWS.d/next/Core and Builtins/2023-03-07-17-37-00.gh-issue-102500.RUSQhz.rst
new file mode 100644
index 00000000000000..e03113ba05cd7d
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-03-07-17-37-00.gh-issue-102500.RUSQhz.rst	
@@ -0,0 +1,3 @@
+Make the buffer protocol accessible in Python code using the new
+``__buffer__`` and ``__release_buffer__`` magic methods. See :pep:`688` for
+details. Patch by Jelle Zijlstra.

From 8e4db4300e3137fd608bc24bfcde3c0098a426e7 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 7 Mar 2023 18:19:13 -0800
Subject: [PATCH 15/35] fix some tests

---
 Lib/inspect.py           | 1 +
 Lib/test/test_doctest.py | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/Lib/inspect.py b/Lib/inspect.py
index 9ab7d61df3a630..86f6f499242c76 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -39,6 +39,7 @@
     "Attribute",
     "BlockFinder",
     "BoundArguments",
+    "BufferFlags",
     "CORO_CLOSED",
     "CORO_CREATED",
     "CORO_RUNNING",
diff --git a/Lib/test/test_doctest.py b/Lib/test/test_doctest.py
index 3491d4cdb1c18b..542fcdb5cf6f66 100644
--- a/Lib/test/test_doctest.py
+++ b/Lib/test/test_doctest.py
@@ -707,7 +707,7 @@ def non_Python_modules(): r"""
 
     >>> import builtins
     >>> tests = doctest.DocTestFinder().find(builtins)
-    >>> 830 < len(tests) < 850 # approximate number of objects with docstrings
+    >>> 830 < len(tests) < 860 # approximate number of objects with docstrings
     True
     >>> real_tests = [t for t in tests if len(t.examples) > 0]
     >>> len(real_tests) # objects that actually have doctests

From 6c863bcf3560563a736ebcefba12c9155a6f7869 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 9 Mar 2023 20:58:41 -0800
Subject: [PATCH 16/35] More tests. Add flags= argument to memoryview

---
 Lib/test/test_buffer.py           | 35 +++++++++++
 Modules/Setup.stdlib.in           |  2 +-
 Modules/_testcapi/buffer.c        | 97 +++++++++++++++++++++++++++++++
 Modules/_testcapi/parts.h         |  1 +
 Modules/_testcapimodule.c         | 90 +---------------------------
 Objects/clinic/memoryobject.c.h   | 26 ++++++---
 Objects/memoryobject.c            |  8 ++-
 PCbuild/_testcapi.vcxproj         |  1 +
 PCbuild/_testcapi.vcxproj.filters |  3 +
 9 files changed, 164 insertions(+), 99 deletions(-)
 create mode 100644 Modules/_testcapi/buffer.c

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index 8b2d7e12fce17b..914cb58675b2b7 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -17,6 +17,7 @@
 import unittest
 from test import support
 from test.support import os_helper
+import inspect
 from itertools import permutations, product
 from random import randrange, sample, choice
 import warnings
@@ -4502,6 +4503,40 @@ def __release_buffer__(self, buffer):
             self.assertEqual(mv.tobytes(), b"hello")
         self.assertFalse(wr.held)
 
+    def test_buffer_flags(self):
+        class PossiblyMutable:
+            def __init__(self, data, mutable) -> None:
+                self._data = bytearray(data)
+                self._mutable = mutable
+
+            def __buffer__(self, flags):
+                if flags & inspect.BufferFlags.WRITABLE:
+                    if not self._mutable:
+                        raise RuntimeError("not mutable")
+                    return memoryview(self._data)
+                else:
+                    return memoryview(bytes(self._data))
+
+        mutable = PossiblyMutable(b"hello", True)
+        immutable = PossiblyMutable(b"hello", False)
+        with memoryview(mutable, flags=inspect.BufferFlags.WRITABLE) as mv:
+            self.assertEqual(mv.tobytes(), b"hello")
+            mv[0] = ord(b'x')
+            self.assertEqual(mv.tobytes(), b"xello")
+        with memoryview(immutable, flags=inspect.BufferFlags.SIMPLE) as mv:
+            self.assertEqual(mv.tobytes(), b"hello")
+            with self.assertRaises(TypeError):
+                mv[0] = ord(b'x')
+            self.assertEqual(mv.tobytes(), b"hello")
+
+        with self.assertRaises(RuntimeError):
+            memoryview(immutable, flags=inspect.BufferFlags.WRITABLE)
+        with memoryview(immutable) as mv:
+            self.assertEqual(mv.tobytes(), b"hello")
+            with self.assertRaises(TypeError):
+                mv[0] = ord(b'x')
+            self.assertEqual(mv.tobytes(), b"hello")
+
     def test_call_builtins(self):
         ba = bytearray(b"hello")
         mv = ba.__buffer__(0)
diff --git a/Modules/Setup.stdlib.in b/Modules/Setup.stdlib.in
index b12290d436cbeb..c5c231ccb33625 100644
--- a/Modules/Setup.stdlib.in
+++ b/Modules/Setup.stdlib.in
@@ -169,7 +169,7 @@
 @MODULE__XXTESTFUZZ_TRUE@_xxtestfuzz _xxtestfuzz/_xxtestfuzz.c _xxtestfuzz/fuzzer.c
 @MODULE__TESTBUFFER_TRUE@_testbuffer _testbuffer.c
 @MODULE__TESTINTERNALCAPI_TRUE@_testinternalcapi _testinternalcapi.c
-@MODULE__TESTCAPI_TRUE@_testcapi _testcapimodule.c _testcapi/vectorcall.c _testcapi/vectorcall_limited.c _testcapi/heaptype.c _testcapi/unicode.c _testcapi/getargs.c _testcapi/pytime.c _testcapi/datetime.c _testcapi/docstring.c _testcapi/mem.c _testcapi/watchers.c _testcapi/long.c _testcapi/float.c _testcapi/structmember.c _testcapi/exceptions.c _testcapi/code.c
+@MODULE__TESTCAPI_TRUE@_testcapi _testcapimodule.c _testcapi/vectorcall.c _testcapi/vectorcall_limited.c _testcapi/heaptype.c _testcapi/unicode.c _testcapi/getargs.c _testcapi/pytime.c _testcapi/datetime.c _testcapi/docstring.c _testcapi/mem.c _testcapi/watchers.c _testcapi/long.c _testcapi/float.c _testcapi/structmember.c _testcapi/exceptions.c _testcapi/code.c _testcapi/buffer.c
 @MODULE__TESTCLINIC_TRUE@_testclinic _testclinic.c
 
 # Some testing modules MUST be built as shared libraries.
diff --git a/Modules/_testcapi/buffer.c b/Modules/_testcapi/buffer.c
new file mode 100644
index 00000000000000..e625e941847c37
--- /dev/null
+++ b/Modules/_testcapi/buffer.c
@@ -0,0 +1,97 @@
+/* Test PEP 688 - Buffers */
+
+#include "parts.h"
+
+#include "structmember.h"           // PyMemberDef
+#include <stddef.h>                 // offsetof
+
+typedef struct {
+    PyObject_HEAD
+    PyObject *obj;
+    long references;
+} testBufObject;
+
+static PyObject *
+testbuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
+{
+    testBufObject *self = (testBufObject *)type->tp_alloc(type, 0);
+    if (self == NULL) {
+        return NULL;
+    }
+    self->obj = PyBytes_FromString("test");
+    self->references = 0;
+    return (PyObject *)self;
+}
+
+static int
+testbuf_traverse(testBufObject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->obj);
+    return 0;
+}
+
+static int
+testbuf_clear(testBufObject *self)
+{
+    Py_CLEAR(self->obj);
+    return 0;
+}
+
+static void
+testbuf_dealloc(testBufObject *self)
+{
+    PyObject_GC_UnTrack(self);
+    Py_XDECREF(self->obj);
+    Py_TYPE(self)->tp_free((PyObject *) self);
+}
+
+static int
+testbuf_getbuf(testBufObject *self, Py_buffer *view, int flags)
+{
+    int buf = PyObject_GetBuffer(self->obj, view, flags);
+    Py_SETREF(view->obj, Py_NewRef((PyObject *)self));
+    self->references++;
+    return buf;
+}
+
+static void
+testbuf_releasebuf(testBufObject *self, Py_buffer *view)
+{
+    self->references--;
+    assert(self->references >= 0);
+}
+
+static PyBufferProcs testbuf_as_buffer = {
+    .bf_getbuffer = (getbufferproc) testbuf_getbuf,
+    .bf_releasebuffer = (releasebufferproc) testbuf_releasebuf,
+};
+
+static struct PyMemberDef testbuf_members[] = {
+    {"references", T_LONG, offsetof(testBufObject, references), READONLY},
+    {NULL},
+};
+
+static PyTypeObject testBufType = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    .tp_name = "testBufType",
+    .tp_basicsize = sizeof(testBufObject),
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
+    .tp_new = testbuf_new,
+    .tp_dealloc = (destructor) testbuf_dealloc,
+    .tp_traverse = (traverseproc) testbuf_traverse,
+    .tp_clear = (inquiry) testbuf_clear,
+    .tp_as_buffer = &testbuf_as_buffer,
+    .tp_members = testbuf_members
+};
+
+int
+_PyTestCapi_Init_Buffer(PyObject *m) {
+    if (PyType_Ready(&testBufType) < 0) {
+        return -1;
+    }
+    if (PyModule_AddObjectRef(m, "testBuf", (PyObject *)&testBufType)) {
+        return -1;
+    }
+
+    return 0;
+}
diff --git a/Modules/_testcapi/parts.h b/Modules/_testcapi/parts.h
index c8f31dc8e39fae..9348ab382344f1 100644
--- a/Modules/_testcapi/parts.h
+++ b/Modules/_testcapi/parts.h
@@ -38,6 +38,7 @@ int _PyTestCapi_Init_Float(PyObject *module);
 int _PyTestCapi_Init_Structmember(PyObject *module);
 int _PyTestCapi_Init_Exceptions(PyObject *module);
 int _PyTestCapi_Init_Code(PyObject *module);
+int _PyTestCapi_Init_Buffer(PyObject *module);
 
 #ifdef LIMITED_API_AVAILABLE
 int _PyTestCapi_Init_VectorcallLimited(PyObject *module);
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index f9ede10dec8eed..0ba964d71bcde3 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -3746,86 +3746,6 @@ static PyTypeObject MyList_Type = {
     MyList_new,                                 /* tp_new */
 };
 
-typedef struct {
-    PyObject_HEAD
-    PyObject *obj;
-    long references;
-} testBufObject;
-
-static PyObject *
-testbuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
-{
-    testBufObject *self = (testBufObject *)type->tp_alloc(type, 0);
-    if (self == NULL) {
-        return NULL;
-    }
-    self->obj = PyBytes_FromString("test");
-    self->references = 0;
-    return (PyObject *)self;
-}
-
-static int
-testbuf_traverse(testBufObject *self, visitproc visit, void *arg)
-{
-    Py_VISIT(self->obj);
-    return 0;
-}
-
-static int
-testbuf_clear(testBufObject *self)
-{
-    Py_CLEAR(self->obj);
-    return 0;
-}
-
-static void
-testbuf_dealloc(testBufObject *self)
-{
-    PyObject_GC_UnTrack(self);
-    Py_XDECREF(self->obj);
-    Py_TYPE(self)->tp_free((PyObject *) self);
-}
-
-static int
-testbuf_getbuf(testBufObject *self, Py_buffer *view, int flags)
-{
-    int buf = PyObject_GetBuffer(self->obj, view, flags);
-    Py_SETREF(view->obj, Py_NewRef((PyObject *)self));
-    self->references++;
-    return buf;
-}
-
-static void
-testbuf_releasebuf(testBufObject *self, Py_buffer *view)
-{
-    self->references--;
-    assert(self->references >= 0);
-}
-
-static PyBufferProcs testbuf_as_buffer = {
-    .bf_getbuffer = (getbufferproc) testbuf_getbuf,
-    .bf_releasebuffer = (releasebufferproc) testbuf_releasebuf,
-};
-
-static struct PyMemberDef testbuf_members[] = {
-    {"references", T_LONG, offsetof(testBufObject, references), READONLY},
-    {NULL},
-};
-
-static PyTypeObject testBufType = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    .tp_name = "testBufType",
-    .tp_basicsize = sizeof(testBufObject),
-    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
-    .tp_new = testbuf_new,
-    .tp_dealloc = (destructor) testbuf_dealloc,
-    .tp_traverse = (traverseproc) testbuf_traverse,
-    .tp_clear = (inquiry) testbuf_clear,
-    .tp_as_buffer = &testbuf_as_buffer,
-    .tp_members = testbuf_members
-};
-
-
 /* Test PEP 560 */
 
 typedef struct {
@@ -4057,13 +3977,6 @@ PyInit__testcapi(void)
     Py_INCREF(&MyList_Type);
     PyModule_AddObject(m, "MyList", (PyObject *)&MyList_Type);
 
-    if (PyType_Ready(&testBufType) < 0) {
-        return NULL;
-    }
-    if (PyModule_AddObjectRef(m, "testBuf", (PyObject *)&testBufType)) {
-        return NULL;
-    }
-
     if (PyType_Ready(&GenericAlias_Type) < 0)
         return NULL;
     Py_INCREF(&GenericAlias_Type);
@@ -4172,6 +4085,9 @@ PyInit__testcapi(void)
     if (_PyTestCapi_Init_Code(m) < 0) {
         return NULL;
     }
+    if (_PyTestCapi_Init_Buffer(m) < 0) {
+        return NULL;
+    }
 
 #ifndef LIMITED_API_AVAILABLE
     PyModule_AddObjectRef(m, "LIMITED_API_AVAILABLE", Py_False);
diff --git a/Objects/clinic/memoryobject.c.h b/Objects/clinic/memoryobject.c.h
index ff7b50bb114b05..1e7ee55ab960ae 100644
--- a/Objects/clinic/memoryobject.c.h
+++ b/Objects/clinic/memoryobject.c.h
@@ -9,13 +9,13 @@ preserve
 
 
 PyDoc_STRVAR(memoryview__doc__,
-"memoryview(object)\n"
+"memoryview(object, *, flags=PyBUF_FULL_RO)\n"
 "--\n"
 "\n"
 "Create a new memoryview object which references the given object.");
 
 static PyObject *
-memoryview_impl(PyTypeObject *type, PyObject *object);
+memoryview_impl(PyTypeObject *type, PyObject *object, int flags);
 
 static PyObject *
 memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
@@ -23,14 +23,14 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     PyObject *return_value = NULL;
     #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
 
-    #define NUM_KEYWORDS 1
+    #define NUM_KEYWORDS 2
     static struct {
         PyGC_Head _this_is_not_used;
         PyObject_VAR_HEAD
         PyObject *ob_item[NUM_KEYWORDS];
     } _kwtuple = {
         .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
-        .ob_item = { &_Py_ID(object), },
+        .ob_item = { &_Py_ID(object), &_Py_ID(flags), },
     };
     #undef NUM_KEYWORDS
     #define KWTUPLE (&_kwtuple.ob_base.ob_base)
@@ -39,24 +39,34 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     #  define KWTUPLE NULL
     #endif  // !Py_BUILD_CORE
 
-    static const char * const _keywords[] = {"object", NULL};
+    static const char * const _keywords[] = {"object", "flags", NULL};
     static _PyArg_Parser _parser = {
         .keywords = _keywords,
         .fname = "memoryview",
         .kwtuple = KWTUPLE,
     };
     #undef KWTUPLE
-    PyObject *argsbuf[1];
+    PyObject *argsbuf[2];
     PyObject * const *fastargs;
     Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *object;
+    int flags = PyBUF_FULL_RO;
 
     fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
     if (!fastargs) {
         goto exit;
     }
     object = fastargs[0];
-    return_value = memoryview_impl(type, object);
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    flags = _PyLong_AsInt(fastargs[1]);
+    if (flags == -1 && PyErr_Occurred()) {
+        goto exit;
+    }
+skip_optional_kwonly:
+    return_value = memoryview_impl(type, object, flags);
 
 exit:
     return return_value;
@@ -356,4 +366,4 @@ memoryview_hex(PyMemoryViewObject *self, PyObject *const *args, Py_ssize_t nargs
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=a832f2fc44e4794c input=a9049054013a1b77]*/
+/*[clinic end generated code: output=9de9bd412f8fea52 input=a9049054013a1b77]*/
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index 9d69a615c537bc..6e8384ce4401bd 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -965,15 +965,17 @@ PyMemoryView_GetContiguous(PyObject *obj, int buffertype, char order)
 memoryview.__new__
 
     object: object
+    *
+    flags: int(c_default='PyBUF_FULL_RO') = PyBUF_FULL_RO
 
 Create a new memoryview object which references the given object.
 [clinic start generated code]*/
 
 static PyObject *
-memoryview_impl(PyTypeObject *type, PyObject *object)
-/*[clinic end generated code: output=7de78e184ed66db8 input=f04429eb0bdf8c6e]*/
+memoryview_impl(PyTypeObject *type, PyObject *object, int flags)
+/*[clinic end generated code: output=f1c225d1ad24ec11 input=cab66ab4bb27f268]*/
 {
-    return PyMemoryView_FromObject(object);
+    return PyMemoryView_FromObjectAndFlags(object, flags);
 }
 
 
diff --git a/PCbuild/_testcapi.vcxproj b/PCbuild/_testcapi.vcxproj
index 4cc184bfc1ac82..6be0aacf57074a 100644
--- a/PCbuild/_testcapi.vcxproj
+++ b/PCbuild/_testcapi.vcxproj
@@ -109,6 +109,7 @@
     <ClCompile Include="..\Modules\_testcapi\structmember.c" />
     <ClCompile Include="..\Modules\_testcapi\exceptions.c" />
     <ClCompile Include="..\Modules\_testcapi\code.c" />
+    <ClCompile Include="..\Modules\_testcapi\buffer.c" />
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="..\PC\python_nt.rc" />
diff --git a/PCbuild/_testcapi.vcxproj.filters b/PCbuild/_testcapi.vcxproj.filters
index fbdaf04ce37cb1..cc4b22361b328a 100644
--- a/PCbuild/_testcapi.vcxproj.filters
+++ b/PCbuild/_testcapi.vcxproj.filters
@@ -57,6 +57,9 @@
     <ClCompile Include="..\Modules\_testcapi\code.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\Modules\_testcapi\buffer.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="..\PC\python_nt.rc">

From 3b4b7d69587ef4a551798560b904246446cd9404 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Fri, 10 Mar 2023 16:54:51 -0800
Subject: [PATCH 17/35] Make memoryview flags arg private

---
 Lib/test/test_buffer.py         |  6 +++---
 Objects/clinic/memoryobject.c.h | 18 +++++++++---------
 Objects/memoryobject.c          |  8 ++++----
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index 914cb58675b2b7..655ecf42176df8 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4519,18 +4519,18 @@ def __buffer__(self, flags):
 
         mutable = PossiblyMutable(b"hello", True)
         immutable = PossiblyMutable(b"hello", False)
-        with memoryview(mutable, flags=inspect.BufferFlags.WRITABLE) as mv:
+        with memoryview(mutable, _flags=inspect.BufferFlags.WRITABLE) as mv:
             self.assertEqual(mv.tobytes(), b"hello")
             mv[0] = ord(b'x')
             self.assertEqual(mv.tobytes(), b"xello")
-        with memoryview(immutable, flags=inspect.BufferFlags.SIMPLE) as mv:
+        with memoryview(immutable, _flags=inspect.BufferFlags.SIMPLE) as mv:
             self.assertEqual(mv.tobytes(), b"hello")
             with self.assertRaises(TypeError):
                 mv[0] = ord(b'x')
             self.assertEqual(mv.tobytes(), b"hello")
 
         with self.assertRaises(RuntimeError):
-            memoryview(immutable, flags=inspect.BufferFlags.WRITABLE)
+            memoryview(immutable, _flags=inspect.BufferFlags.WRITABLE)
         with memoryview(immutable) as mv:
             self.assertEqual(mv.tobytes(), b"hello")
             with self.assertRaises(TypeError):
diff --git a/Objects/clinic/memoryobject.c.h b/Objects/clinic/memoryobject.c.h
index 1e7ee55ab960ae..26f96fc91b832e 100644
--- a/Objects/clinic/memoryobject.c.h
+++ b/Objects/clinic/memoryobject.c.h
@@ -9,13 +9,13 @@ preserve
 
 
 PyDoc_STRVAR(memoryview__doc__,
-"memoryview(object, *, flags=PyBUF_FULL_RO)\n"
+"memoryview(object, *, _flags=PyBUF_FULL_RO)\n"
 "--\n"
 "\n"
 "Create a new memoryview object which references the given object.");
 
 static PyObject *
-memoryview_impl(PyTypeObject *type, PyObject *object, int flags);
+memoryview_impl(PyTypeObject *type, PyObject *object, int _flags);
 
 static PyObject *
 memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
@@ -30,7 +30,7 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
         PyObject *ob_item[NUM_KEYWORDS];
     } _kwtuple = {
         .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
-        .ob_item = { &_Py_ID(object), &_Py_ID(flags), },
+        .ob_item = { &_Py_ID(object), &_Py_ID(_flags), },
     };
     #undef NUM_KEYWORDS
     #define KWTUPLE (&_kwtuple.ob_base.ob_base)
@@ -39,7 +39,7 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     #  define KWTUPLE NULL
     #endif  // !Py_BUILD_CORE
 
-    static const char * const _keywords[] = {"object", "flags", NULL};
+    static const char * const _keywords[] = {"object", "_flags", NULL};
     static _PyArg_Parser _parser = {
         .keywords = _keywords,
         .fname = "memoryview",
@@ -51,7 +51,7 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *object;
-    int flags = PyBUF_FULL_RO;
+    int _flags = PyBUF_FULL_RO;
 
     fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
     if (!fastargs) {
@@ -61,12 +61,12 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     if (!noptargs) {
         goto skip_optional_kwonly;
     }
-    flags = _PyLong_AsInt(fastargs[1]);
-    if (flags == -1 && PyErr_Occurred()) {
+    _flags = _PyLong_AsInt(fastargs[1]);
+    if (_flags == -1 && PyErr_Occurred()) {
         goto exit;
     }
 skip_optional_kwonly:
-    return_value = memoryview_impl(type, object, flags);
+    return_value = memoryview_impl(type, object, _flags);
 
 exit:
     return return_value;
@@ -366,4 +366,4 @@ memoryview_hex(PyMemoryViewObject *self, PyObject *const *args, Py_ssize_t nargs
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=9de9bd412f8fea52 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=392fda9a93c25dd2 input=a9049054013a1b77]*/
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index 6e8384ce4401bd..f119bb5d36d6d1 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -966,16 +966,16 @@ memoryview.__new__
 
     object: object
     *
-    flags: int(c_default='PyBUF_FULL_RO') = PyBUF_FULL_RO
+    _flags: int(c_default='PyBUF_FULL_RO') = PyBUF_FULL_RO
 
 Create a new memoryview object which references the given object.
 [clinic start generated code]*/
 
 static PyObject *
-memoryview_impl(PyTypeObject *type, PyObject *object, int flags)
-/*[clinic end generated code: output=f1c225d1ad24ec11 input=cab66ab4bb27f268]*/
+memoryview_impl(PyTypeObject *type, PyObject *object, int _flags)
+/*[clinic end generated code: output=80388b83c45dafac input=2ea9a227b7f350e8]*/
 {
-    return PyMemoryView_FromObjectAndFlags(object, flags);
+    return PyMemoryView_FromObjectAndFlags(object, _flags);
 }
 
 

From f2950127b84c1888f7db07b56c71d2be0f377064 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Fri, 10 Mar 2023 17:05:59 -0800
Subject: [PATCH 18/35] regen global objects

---
 Include/internal/pycore_global_objects_fini_generated.h | 1 +
 Include/internal/pycore_global_strings.h                | 1 +
 Include/internal/pycore_runtime_init_generated.h        | 1 +
 Include/internal/pycore_unicodeobject_generated.h       | 2 ++
 4 files changed, 5 insertions(+)

diff --git a/Include/internal/pycore_global_objects_fini_generated.h b/Include/internal/pycore_global_objects_fini_generated.h
index 87d2700f991f2c..f60d005dad71a6 100644
--- a/Include/internal/pycore_global_objects_fini_generated.h
+++ b/Include/internal/pycore_global_objects_fini_generated.h
@@ -751,6 +751,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_finalizing));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_find_and_load));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_fix_up_module));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_flags));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_flags_));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_get_sourcefile));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_handle_fromlist));
diff --git a/Include/internal/pycore_global_strings.h b/Include/internal/pycore_global_strings.h
index fb9fefef0db37a..2f431527d69d9f 100644
--- a/Include/internal/pycore_global_strings.h
+++ b/Include/internal/pycore_global_strings.h
@@ -237,6 +237,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(_finalizing)
         STRUCT_FOR_ID(_find_and_load)
         STRUCT_FOR_ID(_fix_up_module)
+        STRUCT_FOR_ID(_flags)
         STRUCT_FOR_ID(_flags_)
         STRUCT_FOR_ID(_get_sourcefile)
         STRUCT_FOR_ID(_handle_fromlist)
diff --git a/Include/internal/pycore_runtime_init_generated.h b/Include/internal/pycore_runtime_init_generated.h
index 77f8f464ad604c..f6d1e2c9095ebd 100644
--- a/Include/internal/pycore_runtime_init_generated.h
+++ b/Include/internal/pycore_runtime_init_generated.h
@@ -743,6 +743,7 @@ extern "C" {
     INIT_ID(_finalizing), \
     INIT_ID(_find_and_load), \
     INIT_ID(_fix_up_module), \
+    INIT_ID(_flags), \
     INIT_ID(_flags_), \
     INIT_ID(_get_sourcefile), \
     INIT_ID(_handle_fromlist), \
diff --git a/Include/internal/pycore_unicodeobject_generated.h b/Include/internal/pycore_unicodeobject_generated.h
index f59f0e716d859c..e6e861f5d4e9e0 100644
--- a/Include/internal/pycore_unicodeobject_generated.h
+++ b/Include/internal/pycore_unicodeobject_generated.h
@@ -380,6 +380,8 @@ _PyUnicode_InitStaticStrings(void) {
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(_fix_up_module);
     PyUnicode_InternInPlace(&string);
+    string = &_Py_ID(_flags);
+    PyUnicode_InternInPlace(&string);
     string = &_Py_ID(_flags_);
     PyUnicode_InternInPlace(&string);
     string = &_Py_ID(_get_sourcefile);

From b5ea9088b8c146faddb28f4bd5d4417e1e0124c5 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 4 Apr 2023 18:13:13 -0700
Subject: [PATCH 19/35] Ignore new C globals for now

---
 Objects/typeobject.c                        | 2 +-
 Tools/c-analyzer/cpython/globals-to-fix.tsv | 1 +
 Tools/c-analyzer/cpython/ignored.tsv        | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 358d1a93eeebbf..b99a008ca65540 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8587,7 +8587,7 @@ static PyBufferProcs bufferwrapper_as_buffer = {
 };
 
 
-PyTypeObject _PyBufferWrapper_Type = {
+static PyTypeObject _PyBufferWrapper_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     .tp_name = "_buffer_wrapper",
     .tp_basicsize = sizeof(PyBufferWrapper),
diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index 0620c7e13925b5..50a32d04b2d285 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -86,6 +86,7 @@ Objects/sliceobject.c	-	PyEllipsis_Type	-
 Objects/sliceobject.c	-	PySlice_Type	-
 Objects/tupleobject.c	-	PyTupleIter_Type	-
 Objects/tupleobject.c	-	PyTuple_Type	-
+Objects/typeobject.c    -   _PyBufferWrapper_Type   -
 Objects/typeobject.c	-	PyBaseObject_Type	-
 Objects/typeobject.c	-	PySuper_Type	-
 Objects/typeobject.c	-	PyType_Type	-
diff --git a/Tools/c-analyzer/cpython/ignored.tsv b/Tools/c-analyzer/cpython/ignored.tsv
index a8ba88efc732fb..58dec8f6bb8556 100644
--- a/Tools/c-analyzer/cpython/ignored.tsv
+++ b/Tools/c-analyzer/cpython/ignored.tsv
@@ -403,6 +403,7 @@ Modules/_testbuffer.c	ndarray_memoryview_from_buffer	strides	-
 Modules/_testbuffer.c	ndarray_memoryview_from_buffer	suboffsets	-
 Modules/_testbuffer.c	ndarray_push	kwlist	-
 Modules/_testbuffer.c	staticarray_init	kwlist	-
+Modules/_testcapi/buffer.c  -   testBufType -
 Modules/_testcapi/code.c	get_code_extra_index	key	-
 Modules/_testcapi/datetime.c	-	test_run_counter	-
 Modules/_testcapi/exceptions.c	-	PyRecursingInfinitelyError_Type	-

From b22bfa95ed7a9220d8767853db3563e9505d09ac Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Tue, 4 Apr 2023 18:14:15 -0700
Subject: [PATCH 20/35] not static (should not have committed this)

---
 Objects/typeobject.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index b99a008ca65540..358d1a93eeebbf 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8587,7 +8587,7 @@ static PyBufferProcs bufferwrapper_as_buffer = {
 };
 
 
-static PyTypeObject _PyBufferWrapper_Type = {
+PyTypeObject _PyBufferWrapper_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     .tp_name = "_buffer_wrapper",
     .tp_basicsize = sizeof(PyBufferWrapper),

From 69e8f7c9b6bddb0188e3dba4834b10b82aac8acd Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Wed, 5 Apr 2023 06:57:20 -0700
Subject: [PATCH 21/35] Use tabs not spaces

---
 Tools/c-analyzer/cpython/globals-to-fix.tsv | 2 +-
 Tools/c-analyzer/cpython/ignored.tsv        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index 50a32d04b2d285..79ca4dc3e2969d 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -86,7 +86,7 @@ Objects/sliceobject.c	-	PyEllipsis_Type	-
 Objects/sliceobject.c	-	PySlice_Type	-
 Objects/tupleobject.c	-	PyTupleIter_Type	-
 Objects/tupleobject.c	-	PyTuple_Type	-
-Objects/typeobject.c    -   _PyBufferWrapper_Type   -
+Objects/typeobject.c	-	_PyBufferWrapper_Type	-
 Objects/typeobject.c	-	PyBaseObject_Type	-
 Objects/typeobject.c	-	PySuper_Type	-
 Objects/typeobject.c	-	PyType_Type	-
diff --git a/Tools/c-analyzer/cpython/ignored.tsv b/Tools/c-analyzer/cpython/ignored.tsv
index 58dec8f6bb8556..f3f8f831c48044 100644
--- a/Tools/c-analyzer/cpython/ignored.tsv
+++ b/Tools/c-analyzer/cpython/ignored.tsv
@@ -403,7 +403,7 @@ Modules/_testbuffer.c	ndarray_memoryview_from_buffer	strides	-
 Modules/_testbuffer.c	ndarray_memoryview_from_buffer	suboffsets	-
 Modules/_testbuffer.c	ndarray_push	kwlist	-
 Modules/_testbuffer.c	staticarray_init	kwlist	-
-Modules/_testcapi/buffer.c  -   testBufType -
+Modules/_testcapi/buffer.c	-	testBufType	-
 Modules/_testcapi/code.c	get_code_extra_index	key	-
 Modules/_testcapi/datetime.c	-	test_run_counter	-
 Modules/_testcapi/exceptions.c	-	PyRecursingInfinitelyError_Type	-

From 4ca7a7c5f97ffd20eee255abeddb7650dd67cee4 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Sun, 9 Apr 2023 21:17:32 -0700
Subject: [PATCH 22/35] Address Kumar's feedback

---
 .../pycore_global_objects_fini_generated.h    |  1 +
 Include/internal/pycore_global_strings.h      |  1 +
 .../internal/pycore_runtime_init_generated.h  |  1 +
 .../internal/pycore_unicodeobject_generated.h |  3 +++
 Modules/_testcapi/buffer.c                    |  9 +++++--
 Objects/typeobject.c                          | 25 +++++++++----------
 6 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/Include/internal/pycore_global_objects_fini_generated.h b/Include/internal/pycore_global_objects_fini_generated.h
index 8294f5764c83b4..aa8055bc3ec370 100644
--- a/Include/internal/pycore_global_objects_fini_generated.h
+++ b/Include/internal/pycore_global_objects_fini_generated.h
@@ -1123,6 +1123,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(reducer_override));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(registry));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(rel_tol));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(release));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(reload));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(repl));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(replace));
diff --git a/Include/internal/pycore_global_strings.h b/Include/internal/pycore_global_strings.h
index 278c69ca687327..3babba2196753b 100644
--- a/Include/internal/pycore_global_strings.h
+++ b/Include/internal/pycore_global_strings.h
@@ -609,6 +609,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(reducer_override)
         STRUCT_FOR_ID(registry)
         STRUCT_FOR_ID(rel_tol)
+        STRUCT_FOR_ID(release)
         STRUCT_FOR_ID(reload)
         STRUCT_FOR_ID(repl)
         STRUCT_FOR_ID(replace)
diff --git a/Include/internal/pycore_runtime_init_generated.h b/Include/internal/pycore_runtime_init_generated.h
index 62e0575fbcdbbe..4a8f280be337af 100644
--- a/Include/internal/pycore_runtime_init_generated.h
+++ b/Include/internal/pycore_runtime_init_generated.h
@@ -1115,6 +1115,7 @@ extern "C" {
     INIT_ID(reducer_override), \
     INIT_ID(registry), \
     INIT_ID(rel_tol), \
+    INIT_ID(release), \
     INIT_ID(reload), \
     INIT_ID(repl), \
     INIT_ID(replace), \
diff --git a/Include/internal/pycore_unicodeobject_generated.h b/Include/internal/pycore_unicodeobject_generated.h
index 168e6147345c3c..f562a8c7bc147a 100644
--- a/Include/internal/pycore_unicodeobject_generated.h
+++ b/Include/internal/pycore_unicodeobject_generated.h
@@ -1680,6 +1680,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(rel_tol);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(release);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(reload);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
diff --git a/Modules/_testcapi/buffer.c b/Modules/_testcapi/buffer.c
index e625e941847c37..29ca2c7fd91448 100644
--- a/Modules/_testcapi/buffer.c
+++ b/Modules/_testcapi/buffer.c
@@ -8,17 +8,22 @@
 typedef struct {
     PyObject_HEAD
     PyObject *obj;
-    long references;
+    Py_ssize_t references;
 } testBufObject;
 
 static PyObject *
 testbuf_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 {
+    PyObject *obj = PyBytes_FromString("test");
+    if (obj == NULL) {
+        return NULL;
+    }
     testBufObject *self = (testBufObject *)type->tp_alloc(type, 0);
     if (self == NULL) {
+        Py_DECREF(obj);
         return NULL;
     }
-    self->obj = PyBytes_FromString("test");
+    self->obj = obj;
     self->references = 0;
     return (PyObject *)self;
 }
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 358d1a93eeebbf..3d0c91e1cdd5ab 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -7665,28 +7665,32 @@ wrap_descr_delete(PyObject *self, PyObject *args, void *wrapped)
 static PyObject *
 wrap_buffer(PyObject *self, PyObject *args, void *wrapped)
 {
-    int flags = 0;
+    PyObject *arg = NULL;
 
-    if (!check_num_args(args, 1)) {
+    if (!PyArg_UnpackTuple(args, "", 1, 1, &arg)) {
         return NULL;
     }
-    if (!PyArg_ParseTuple(args, "i", &flags)) {
+    Py_ssize_t flags = PyNumber_AsSsize_t(arg, PyExc_OverflowError);
+    if (flags == -1 && PyErr_Occurred()) {
         return NULL;
     }
+
     return PyMemoryView_FromObjectAndFlags(self, flags);
 }
 
 static PyObject *
 wrap_releasebuffer(PyObject *self, PyObject *args, void *wrapped)
 {
-    PyMemoryViewObject *mview;
-
-    if (!check_num_args(args, 1)) {
+    PyObject *arg = NULL;
+    if (!PyArg_UnpackTuple(args, "", 1, 1, &arg)) {
         return NULL;
     }
-    if (!PyArg_ParseTuple(args, "O!", &PyMemoryView_Type, &mview)) {
+    if (!PyMemoryView_Check(arg)) {
+        PyErr_SetString(PyExc_TypeError,
+                        "expected a memoryview object");
         return NULL;
     }
+    PyMemoryViewObject *mview = (PyMemoryViewObject *)arg;
     if (mview->view.obj != self) {
         PyErr_SetString(PyExc_ValueError,
                         "memoryview's buffer is not this object");
@@ -7697,12 +7701,7 @@ wrap_releasebuffer(PyObject *self, PyObject *args, void *wrapped)
                         "memoryview's buffer has already been released");
         return NULL;
     }
-    PyObject *release = PyUnicode_FromString("release");
-    if (release == NULL) {
-        return NULL;
-    }
-    PyObject *res = PyObject_CallMethodNoArgs((PyObject *)mview, release);
-    Py_DECREF(release);
+    PyObject *res = PyObject_CallMethodNoArgs((PyObject *)mview, &_Py_ID(release));
     if (res == NULL) {
         return NULL;
     }

From a70e12d3206d1b76ea4069c82c9d437e3b84c468 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Wed, 12 Apr 2023 17:57:08 -0700
Subject: [PATCH 23/35] Address another piece of feedback

---
 Objects/typeobject.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 9d0c67a1f5a969..b99a45f2aa77a1 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8545,12 +8545,10 @@ typedef struct _PyBufferWrapper {
 } PyBufferWrapper;
 
 static int
-bufferwrapper_traverse(PyObject *self, visitproc visit, void *arg)
+bufferwrapper_traverse(PyBufferWrapper *self, visitproc visit, void *arg)
 {
-    PyBufferWrapper *bw = (PyBufferWrapper *)self;
-
-    Py_VISIT(bw->mv);
-    Py_VISIT(bw->obj);
+    Py_VISIT(self->mv);
+    Py_VISIT(self->obj);
     return 0;
 }
 
@@ -8590,7 +8588,7 @@ PyTypeObject _PyBufferWrapper_Type = {
     .tp_alloc = PyType_GenericAlloc,
     .tp_new = PyType_GenericNew,
     .tp_free = PyObject_GC_Del,
-    .tp_traverse = bufferwrapper_traverse,
+    .tp_traverse = (traverseproc)bufferwrapper_traverse,
     .tp_dealloc = bufferwrapper_dealloc,
     .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
     .tp_as_buffer = &bufferwrapper_as_buffer,

From 96c9253833528dcdfb42e277a23ecab826c5cb36 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Wed, 12 Apr 2023 18:10:50 -0700
Subject: [PATCH 24/35] Use a classmethod instead of a new arg to the
 memoryview constructor

---
 Lib/test/test_buffer.py         |  6 +--
 Objects/clinic/memoryobject.c.h | 78 +++++++++++++++++++++++++++------
 Objects/memoryobject.c          | 25 +++++++++--
 3 files changed, 88 insertions(+), 21 deletions(-)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index 655ecf42176df8..4f9e655f2612ff 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4519,18 +4519,18 @@ def __buffer__(self, flags):
 
         mutable = PossiblyMutable(b"hello", True)
         immutable = PossiblyMutable(b"hello", False)
-        with memoryview(mutable, _flags=inspect.BufferFlags.WRITABLE) as mv:
+        with memoryview._from_flags(mutable, inspect.BufferFlags.WRITABLE) as mv:
             self.assertEqual(mv.tobytes(), b"hello")
             mv[0] = ord(b'x')
             self.assertEqual(mv.tobytes(), b"xello")
-        with memoryview(immutable, _flags=inspect.BufferFlags.SIMPLE) as mv:
+        with memoryview._from_flags(immutable, inspect.BufferFlags.SIMPLE) as mv:
             self.assertEqual(mv.tobytes(), b"hello")
             with self.assertRaises(TypeError):
                 mv[0] = ord(b'x')
             self.assertEqual(mv.tobytes(), b"hello")
 
         with self.assertRaises(RuntimeError):
-            memoryview(immutable, _flags=inspect.BufferFlags.WRITABLE)
+            memoryview_from_flags(immutable, inspect.BufferFlags.WRITABLE)
         with memoryview(immutable) as mv:
             self.assertEqual(mv.tobytes(), b"hello")
             with self.assertRaises(TypeError):
diff --git a/Objects/clinic/memoryobject.c.h b/Objects/clinic/memoryobject.c.h
index 26f96fc91b832e..ead1af4f3e8619 100644
--- a/Objects/clinic/memoryobject.c.h
+++ b/Objects/clinic/memoryobject.c.h
@@ -9,13 +9,13 @@ preserve
 
 
 PyDoc_STRVAR(memoryview__doc__,
-"memoryview(object, *, _flags=PyBUF_FULL_RO)\n"
+"memoryview(object)\n"
 "--\n"
 "\n"
 "Create a new memoryview object which references the given object.");
 
 static PyObject *
-memoryview_impl(PyTypeObject *type, PyObject *object, int _flags);
+memoryview_impl(PyTypeObject *type, PyObject *object);
 
 static PyObject *
 memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
@@ -23,14 +23,14 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     PyObject *return_value = NULL;
     #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
 
-    #define NUM_KEYWORDS 2
+    #define NUM_KEYWORDS 1
     static struct {
         PyGC_Head _this_is_not_used;
         PyObject_VAR_HEAD
         PyObject *ob_item[NUM_KEYWORDS];
     } _kwtuple = {
         .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
-        .ob_item = { &_Py_ID(object), &_Py_ID(_flags), },
+        .ob_item = { &_Py_ID(object), },
     };
     #undef NUM_KEYWORDS
     #define KWTUPLE (&_kwtuple.ob_base.ob_base)
@@ -39,34 +39,84 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
     #  define KWTUPLE NULL
     #endif  // !Py_BUILD_CORE
 
-    static const char * const _keywords[] = {"object", "_flags", NULL};
+    static const char * const _keywords[] = {"object", NULL};
     static _PyArg_Parser _parser = {
         .keywords = _keywords,
         .fname = "memoryview",
         .kwtuple = KWTUPLE,
     };
     #undef KWTUPLE
-    PyObject *argsbuf[2];
+    PyObject *argsbuf[1];
     PyObject * const *fastargs;
     Py_ssize_t nargs = PyTuple_GET_SIZE(args);
-    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
     PyObject *object;
-    int _flags = PyBUF_FULL_RO;
 
     fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
     if (!fastargs) {
         goto exit;
     }
     object = fastargs[0];
-    if (!noptargs) {
-        goto skip_optional_kwonly;
+    return_value = memoryview_impl(type, object);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(memoryview__from_flags__doc__,
+"_from_flags($type, /, object, _flags)\n"
+"--\n"
+"\n"
+"Create a new memoryview object which references the given object.");
+
+#define MEMORYVIEW__FROM_FLAGS_METHODDEF    \
+    {"_from_flags", _PyCFunction_CAST(memoryview__from_flags), METH_FASTCALL|METH_KEYWORDS|METH_CLASS, memoryview__from_flags__doc__},
+
+static PyObject *
+memoryview__from_flags_impl(PyTypeObject *type, PyObject *object, int _flags);
+
+static PyObject *
+memoryview__from_flags(PyTypeObject *type, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 2
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(object), &_Py_ID(_flags), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"object", "_flags", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "_from_flags",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[2];
+    PyObject *object;
+    int _flags;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
     }
-    _flags = _PyLong_AsInt(fastargs[1]);
+    object = args[0];
+    _flags = _PyLong_AsInt(args[1]);
     if (_flags == -1 && PyErr_Occurred()) {
         goto exit;
     }
-skip_optional_kwonly:
-    return_value = memoryview_impl(type, object, _flags);
+    return_value = memoryview__from_flags_impl(type, object, _flags);
 
 exit:
     return return_value;
@@ -366,4 +416,4 @@ memoryview_hex(PyMemoryViewObject *self, PyObject *const *args, Py_ssize_t nargs
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=392fda9a93c25dd2 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=31ed11a9a4ac95c4 input=a9049054013a1b77]*/
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index f119bb5d36d6d1..9117c3236baeb7 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -965,15 +965,31 @@ PyMemoryView_GetContiguous(PyObject *obj, int buffertype, char order)
 memoryview.__new__
 
     object: object
-    *
-    _flags: int(c_default='PyBUF_FULL_RO') = PyBUF_FULL_RO
 
 Create a new memoryview object which references the given object.
 [clinic start generated code]*/
 
 static PyObject *
-memoryview_impl(PyTypeObject *type, PyObject *object, int _flags)
-/*[clinic end generated code: output=80388b83c45dafac input=2ea9a227b7f350e8]*/
+memoryview_impl(PyTypeObject *type, PyObject *object)
+/*[clinic end generated code: output=7de78e184ed66db8 input=f04429eb0bdf8c6e]*/
+{
+    return PyMemoryView_FromObject(object);
+}
+
+
+/*[clinic input]
+@classmethod
+memoryview._from_flags
+
+    object: object
+    _flags: int
+
+Create a new memoryview object which references the given object.
+[clinic start generated code]*/
+
+static PyObject *
+memoryview__from_flags_impl(PyTypeObject *type, PyObject *object, int _flags)
+/*[clinic end generated code: output=bc1f4ba7d9b64525 input=860e7832e8edb1e5]*/
 {
     return PyMemoryView_FromObjectAndFlags(object, _flags);
 }
@@ -3191,6 +3207,7 @@ static PyMethodDef memory_methods[] = {
     MEMORYVIEW_TOLIST_METHODDEF
     MEMORYVIEW_CAST_METHODDEF
     MEMORYVIEW_TOREADONLY_METHODDEF
+    MEMORYVIEW__FROM_FLAGS_METHODDEF
     {"__enter__",   memory_enter, METH_NOARGS, NULL},
     {"__exit__",    memory_exit, METH_VARARGS, NULL},
     {NULL,          NULL}

From 1f7f7a090be30a2806976385da3c050b5afe2ef1 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 13 Apr 2023 12:05:28 -0700
Subject: [PATCH 25/35] fix typo

---
 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 4f9e655f2612ff..e0b3e81af63071 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4530,7 +4530,7 @@ def __buffer__(self, flags):
             self.assertEqual(mv.tobytes(), b"hello")
 
         with self.assertRaises(RuntimeError):
-            memoryview_from_flags(immutable, inspect.BufferFlags.WRITABLE)
+            memoryview._from_flags(immutable, inspect.BufferFlags.WRITABLE)
         with memoryview(immutable) as mv:
             self.assertEqual(mv.tobytes(), b"hello")
             with self.assertRaises(TypeError):

From 33691eab4e61bea7e55f2cdb52f1bfe71ab8a34c Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Wed, 26 Apr 2023 06:22:49 -0600
Subject: [PATCH 26/35] Add Py_SAFE_DOWNCAST

---
 Include/internal/pycore_global_objects_fini_generated.h | 3 +++
 Include/internal/pycore_global_strings.h                | 3 +++
 Include/internal/pycore_runtime_init_generated.h        | 3 +++
 Include/internal/pycore_unicodeobject_generated.h       | 9 +++++++++
 Objects/typeobject.c                                    | 2 +-
 5 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/Include/internal/pycore_global_objects_fini_generated.h b/Include/internal/pycore_global_objects_fini_generated.h
index b157724b8ab30a..a79ea65b5bf0dd 100644
--- a/Include/internal/pycore_global_objects_fini_generated.h
+++ b/Include/internal/pycore_global_objects_fini_generated.h
@@ -780,8 +780,10 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(after_in_child));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(after_in_parent));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(aggregate_class));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(alias));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(append));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(argdefs));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(args));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(arguments));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(argv));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(as_integer_ratio));
@@ -1076,6 +1078,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(optimize));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(options));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(order));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(origin));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(out_fd));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(outgoing));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(overlapped));
diff --git a/Include/internal/pycore_global_strings.h b/Include/internal/pycore_global_strings.h
index 3babba2196753b..34f89e3c25d49a 100644
--- a/Include/internal/pycore_global_strings.h
+++ b/Include/internal/pycore_global_strings.h
@@ -268,8 +268,10 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(after_in_child)
         STRUCT_FOR_ID(after_in_parent)
         STRUCT_FOR_ID(aggregate_class)
+        STRUCT_FOR_ID(alias)
         STRUCT_FOR_ID(append)
         STRUCT_FOR_ID(argdefs)
+        STRUCT_FOR_ID(args)
         STRUCT_FOR_ID(arguments)
         STRUCT_FOR_ID(argv)
         STRUCT_FOR_ID(as_integer_ratio)
@@ -564,6 +566,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(optimize)
         STRUCT_FOR_ID(options)
         STRUCT_FOR_ID(order)
+        STRUCT_FOR_ID(origin)
         STRUCT_FOR_ID(out_fd)
         STRUCT_FOR_ID(outgoing)
         STRUCT_FOR_ID(overlapped)
diff --git a/Include/internal/pycore_runtime_init_generated.h b/Include/internal/pycore_runtime_init_generated.h
index 4a8f280be337af..c7c61ebbd29cbd 100644
--- a/Include/internal/pycore_runtime_init_generated.h
+++ b/Include/internal/pycore_runtime_init_generated.h
@@ -774,8 +774,10 @@ extern "C" {
     INIT_ID(after_in_child), \
     INIT_ID(after_in_parent), \
     INIT_ID(aggregate_class), \
+    INIT_ID(alias), \
     INIT_ID(append), \
     INIT_ID(argdefs), \
+    INIT_ID(args), \
     INIT_ID(arguments), \
     INIT_ID(argv), \
     INIT_ID(as_integer_ratio), \
@@ -1070,6 +1072,7 @@ extern "C" {
     INIT_ID(optimize), \
     INIT_ID(options), \
     INIT_ID(order), \
+    INIT_ID(origin), \
     INIT_ID(out_fd), \
     INIT_ID(outgoing), \
     INIT_ID(overlapped), \
diff --git a/Include/internal/pycore_unicodeobject_generated.h b/Include/internal/pycore_unicodeobject_generated.h
index f562a8c7bc147a..43578138c8ba5b 100644
--- a/Include/internal/pycore_unicodeobject_generated.h
+++ b/Include/internal/pycore_unicodeobject_generated.h
@@ -657,12 +657,18 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(aggregate_class);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(alias);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(append);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(argdefs);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(args);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(arguments);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -1545,6 +1551,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(order);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(origin);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(out_fd);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 73bd3e3b31d594..0ecad2341fbca4 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -7698,7 +7698,7 @@ wrap_buffer(PyObject *self, PyObject *args, void *wrapped)
         return NULL;
     }
 
-    return PyMemoryView_FromObjectAndFlags(self, flags);
+    return PyMemoryView_FromObjectAndFlags(self, Py_SAFE_DOWNCAST(flags, Py_ssize_t, int));
 }
 
 static PyObject *

From 8f5073f400d35df3eb4b188257344b5289866f16 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Wed, 26 Apr 2023 15:42:00 -0600
Subject: [PATCH 27/35] Add some test cases (thanks Shantanu)

---
 Lib/test/test_buffer.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index c09d923274d528..6a2b53892280bc 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4456,6 +4456,12 @@ def __buffer__(self, flags):
 
         self.assertRaises(TypeError, memoryview, MustReturnMV())
 
+        class NoBytesEither:
+            def __buffer__(self, flags):
+                return b"hello"
+
+        self.assertRaises(TypeError, memoryview, NoBytesEither())
+
         class WrongArity:
             def __buffer__(self):
                 return memoryview(b"hello")
@@ -4525,6 +4531,11 @@ def __buffer__(self, flags):
             self.assertEqual(mv.tobytes(), b"hello")
             mv[0] = ord(b'x')
             self.assertEqual(mv.tobytes(), b"xello")
+        with memoryview._from_flags(mutable, inspect.BufferFlags.SIMPLE) as mv:
+            self.assertEqual(mv.tobytes(), b"xello")
+            with self.assertRaises(TypeError):
+                mv[0] = ord(b'h')
+            self.assertEqual(mv.tobytes(), b"xello")
         with memoryview._from_flags(immutable, inspect.BufferFlags.SIMPLE) as mv:
             self.assertEqual(mv.tobytes(), b"hello")
             with self.assertRaises(TypeError):

From cecb6a58027cd6b73519cfb97da5a34ce9d19f48 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Fri, 28 Apr 2023 20:44:29 -0700
Subject: [PATCH 28/35] Remove spurious global strings

---
 Include/internal/pycore_global_objects_fini_generated.h | 3 ---
 Include/internal/pycore_global_strings.h                | 3 ---
 Include/internal/pycore_runtime_init_generated.h        | 3 ---
 Include/internal/pycore_unicodeobject_generated.h       | 9 ---------
 4 files changed, 18 deletions(-)

diff --git a/Include/internal/pycore_global_objects_fini_generated.h b/Include/internal/pycore_global_objects_fini_generated.h
index ae17f28c6b9e60..f3acefd5aca13e 100644
--- a/Include/internal/pycore_global_objects_fini_generated.h
+++ b/Include/internal/pycore_global_objects_fini_generated.h
@@ -780,10 +780,8 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(after_in_child));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(after_in_parent));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(aggregate_class));
-    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(alias));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(append));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(argdefs));
-    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(args));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(arguments));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(argv));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(as_integer_ratio));
@@ -1079,7 +1077,6 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(optimize));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(options));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(order));
-    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(origin));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(out_fd));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(outgoing));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(overlapped));
diff --git a/Include/internal/pycore_global_strings.h b/Include/internal/pycore_global_strings.h
index 033faa9752347e..e250528c91379b 100644
--- a/Include/internal/pycore_global_strings.h
+++ b/Include/internal/pycore_global_strings.h
@@ -268,10 +268,8 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(after_in_child)
         STRUCT_FOR_ID(after_in_parent)
         STRUCT_FOR_ID(aggregate_class)
-        STRUCT_FOR_ID(alias)
         STRUCT_FOR_ID(append)
         STRUCT_FOR_ID(argdefs)
-        STRUCT_FOR_ID(args)
         STRUCT_FOR_ID(arguments)
         STRUCT_FOR_ID(argv)
         STRUCT_FOR_ID(as_integer_ratio)
@@ -567,7 +565,6 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(optimize)
         STRUCT_FOR_ID(options)
         STRUCT_FOR_ID(order)
-        STRUCT_FOR_ID(origin)
         STRUCT_FOR_ID(out_fd)
         STRUCT_FOR_ID(outgoing)
         STRUCT_FOR_ID(overlapped)
diff --git a/Include/internal/pycore_runtime_init_generated.h b/Include/internal/pycore_runtime_init_generated.h
index ecf13a054bbd7e..fcf12e28476ae6 100644
--- a/Include/internal/pycore_runtime_init_generated.h
+++ b/Include/internal/pycore_runtime_init_generated.h
@@ -774,10 +774,8 @@ extern "C" {
     INIT_ID(after_in_child), \
     INIT_ID(after_in_parent), \
     INIT_ID(aggregate_class), \
-    INIT_ID(alias), \
     INIT_ID(append), \
     INIT_ID(argdefs), \
-    INIT_ID(args), \
     INIT_ID(arguments), \
     INIT_ID(argv), \
     INIT_ID(as_integer_ratio), \
@@ -1073,7 +1071,6 @@ extern "C" {
     INIT_ID(optimize), \
     INIT_ID(options), \
     INIT_ID(order), \
-    INIT_ID(origin), \
     INIT_ID(out_fd), \
     INIT_ID(outgoing), \
     INIT_ID(overlapped), \
diff --git a/Include/internal/pycore_unicodeobject_generated.h b/Include/internal/pycore_unicodeobject_generated.h
index d2fd3382c78e0c..c5720add585ea9 100644
--- a/Include/internal/pycore_unicodeobject_generated.h
+++ b/Include/internal/pycore_unicodeobject_generated.h
@@ -657,18 +657,12 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(aggregate_class);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
-    string = &_Py_ID(alias);
-    assert(_PyUnicode_CheckConsistency(string, 1));
-    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(append);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(argdefs);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
-    string = &_Py_ID(args);
-    assert(_PyUnicode_CheckConsistency(string, 1));
-    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(arguments);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -1554,9 +1548,6 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(order);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
-    string = &_Py_ID(origin);
-    assert(_PyUnicode_CheckConsistency(string, 1));
-    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(out_fd);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);

From 0f77bbb8331e057f33062a6d18a16215df9faa34 Mon Sep 17 00:00:00 2001
From: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Date: Thu, 4 May 2023 16:52:17 +0530
Subject: [PATCH 29/35] fixup global objects

---
 Tools/build/generate_global_objects.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Tools/build/generate_global_objects.py b/Tools/build/generate_global_objects.py
index c27817702bf97d..ded19ee489e79b 100644
--- a/Tools/build/generate_global_objects.py
+++ b/Tools/build/generate_global_objects.py
@@ -121,6 +121,8 @@
     '__xor__',
     '__divmod__',
     '__rdivmod__',
+    '__buffer__',
+    '__release_buffer__',
 ]
 
 NON_GENERATED_IMMORTAL_OBJECTS = [

From 61f54ced1d015c43a6d5e4223b6d1aa43356beb6 Mon Sep 17 00:00:00 2001
From: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Date: Thu, 4 May 2023 17:02:22 +0530
Subject: [PATCH 30/35] minor fixes

---
 Modules/_testcapi/buffer.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Modules/_testcapi/buffer.c b/Modules/_testcapi/buffer.c
index 29ca2c7fd91448..aff9a477eff57e 100644
--- a/Modules/_testcapi/buffer.c
+++ b/Modules/_testcapi/buffer.c
@@ -54,7 +54,7 @@ static int
 testbuf_getbuf(testBufObject *self, Py_buffer *view, int flags)
 {
     int buf = PyObject_GetBuffer(self->obj, view, flags);
-    Py_SETREF(view->obj, Py_NewRef((PyObject *)self));
+    Py_SETREF(view->obj, Py_NewRef(self));
     self->references++;
     return buf;
 }
@@ -72,7 +72,7 @@ static PyBufferProcs testbuf_as_buffer = {
 };
 
 static struct PyMemberDef testbuf_members[] = {
-    {"references", T_LONG, offsetof(testBufObject, references), READONLY},
+    {"references", T_PYSSIZET, offsetof(testBufObject, references), READONLY},
     {NULL},
 };
 

From 9f2d16ba327dd3ffc5981940cb6acfac7aa50140 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 4 May 2023 05:59:35 -0700
Subject: [PATCH 31/35] newlines

---
 Lib/test/test_buffer.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index 6a2b53892280bc..ffe40ca9ea2633 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4473,11 +4473,13 @@ class WhatToRelease:
             def __init__(self):
                 self.held = False
                 self.ba = bytearray(b"hello")
+
             def __buffer__(self, flags):
                 if self.held:
                     raise TypeError("already held")
                 self.held = True
                 return memoryview(self.ba)
+
             def __release_buffer__(self, buffer):
                 self.held = False
 
@@ -4494,12 +4496,14 @@ def __init__(self):
                 self.held = False
                 self.ba = bytearray(b"hello")
                 self.created_mv = None
+
             def __buffer__(self, flags):
                 if self.held:
                     raise TypeError("already held")
                 self.held = True
                 self.created_mv = memoryview(self.ba)
                 return self.created_mv
+
             def __release_buffer__(self, buffer):
                 assert buffer is self.created_mv
                 self.held = False

From 5e0d2de8d34d10c0cb6adf2867493bc2fed8d2b2 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 4 May 2023 06:09:04 -0700
Subject: [PATCH 32/35] Rename variable

---
 Objects/clinic/memoryobject.c.h | 18 +++++++++---------
 Objects/memoryobject.c          |  8 ++++----
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/Objects/clinic/memoryobject.c.h b/Objects/clinic/memoryobject.c.h
index ead1af4f3e8619..25a22341185903 100644
--- a/Objects/clinic/memoryobject.c.h
+++ b/Objects/clinic/memoryobject.c.h
@@ -63,7 +63,7 @@ memoryview(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 }
 
 PyDoc_STRVAR(memoryview__from_flags__doc__,
-"_from_flags($type, /, object, _flags)\n"
+"_from_flags($type, /, object, flags)\n"
 "--\n"
 "\n"
 "Create a new memoryview object which references the given object.");
@@ -72,7 +72,7 @@ PyDoc_STRVAR(memoryview__from_flags__doc__,
     {"_from_flags", _PyCFunction_CAST(memoryview__from_flags), METH_FASTCALL|METH_KEYWORDS|METH_CLASS, memoryview__from_flags__doc__},
 
 static PyObject *
-memoryview__from_flags_impl(PyTypeObject *type, PyObject *object, int _flags);
+memoryview__from_flags_impl(PyTypeObject *type, PyObject *object, int flags);
 
 static PyObject *
 memoryview__from_flags(PyTypeObject *type, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
@@ -87,7 +87,7 @@ memoryview__from_flags(PyTypeObject *type, PyObject *const *args, Py_ssize_t nar
         PyObject *ob_item[NUM_KEYWORDS];
     } _kwtuple = {
         .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
-        .ob_item = { &_Py_ID(object), &_Py_ID(_flags), },
+        .ob_item = { &_Py_ID(object), &_Py_ID(flags), },
     };
     #undef NUM_KEYWORDS
     #define KWTUPLE (&_kwtuple.ob_base.ob_base)
@@ -96,7 +96,7 @@ memoryview__from_flags(PyTypeObject *type, PyObject *const *args, Py_ssize_t nar
     #  define KWTUPLE NULL
     #endif  // !Py_BUILD_CORE
 
-    static const char * const _keywords[] = {"object", "_flags", NULL};
+    static const char * const _keywords[] = {"object", "flags", NULL};
     static _PyArg_Parser _parser = {
         .keywords = _keywords,
         .fname = "_from_flags",
@@ -105,18 +105,18 @@ memoryview__from_flags(PyTypeObject *type, PyObject *const *args, Py_ssize_t nar
     #undef KWTUPLE
     PyObject *argsbuf[2];
     PyObject *object;
-    int _flags;
+    int flags;
 
     args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
     if (!args) {
         goto exit;
     }
     object = args[0];
-    _flags = _PyLong_AsInt(args[1]);
-    if (_flags == -1 && PyErr_Occurred()) {
+    flags = _PyLong_AsInt(args[1]);
+    if (flags == -1 && PyErr_Occurred()) {
         goto exit;
     }
-    return_value = memoryview__from_flags_impl(type, object, _flags);
+    return_value = memoryview__from_flags_impl(type, object, flags);
 
 exit:
     return return_value;
@@ -416,4 +416,4 @@ memoryview_hex(PyMemoryViewObject *self, PyObject *const *args, Py_ssize_t nargs
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=31ed11a9a4ac95c4 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=01613814112cedd7 input=a9049054013a1b77]*/
diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c
index 8c913bcdac9cf9..f008a8cc3e0474 100644
--- a/Objects/memoryobject.c
+++ b/Objects/memoryobject.c
@@ -982,16 +982,16 @@ memoryview_impl(PyTypeObject *type, PyObject *object)
 memoryview._from_flags
 
     object: object
-    _flags: int
+    flags: int
 
 Create a new memoryview object which references the given object.
 [clinic start generated code]*/
 
 static PyObject *
-memoryview__from_flags_impl(PyTypeObject *type, PyObject *object, int _flags)
-/*[clinic end generated code: output=bc1f4ba7d9b64525 input=860e7832e8edb1e5]*/
+memoryview__from_flags_impl(PyTypeObject *type, PyObject *object, int flags)
+/*[clinic end generated code: output=bf71f9906c266ee2 input=f5f82fd0e744356b]*/
 {
-    return PyMemoryView_FromObjectAndFlags(object, _flags);
+    return PyMemoryView_FromObjectAndFlags(object, flags);
 }
 
 

From b3806322bcebca57c8f4f942c70b00a989223ee7 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 4 May 2023 06:11:34 -0700
Subject: [PATCH 33/35] Check for INT_MAX

---
 Lib/test/test_buffer.py | 2 ++
 Objects/typeobject.c    | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/Lib/test/test_buffer.py b/Lib/test/test_buffer.py
index ffe40ca9ea2633..b6e82ad4db266a 100644
--- a/Lib/test/test_buffer.py
+++ b/Lib/test/test_buffer.py
@@ -4559,6 +4559,8 @@ def test_call_builtins(self):
         mv = ba.__buffer__(0)
         self.assertEqual(mv.tobytes(), b"hello")
         ba.__release_buffer__(mv)
+        with self.assertRaises(OverflowError):
+            ba.__buffer__(sys.maxsize + 1)
 
     @unittest.skipIf(_testcapi is None, "requires _testcapi")
     def test_c_buffer(self):
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index f7ad15f70baf29..500e3d782a3eea 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8072,6 +8072,11 @@ wrap_buffer(PyObject *self, PyObject *args, void *wrapped)
     if (flags == -1 && PyErr_Occurred()) {
         return NULL;
     }
+    if (flags > INT_MAX) {
+        PyErr_SetString(PyExc_OverflowError,
+                        "buffer flags too large");
+        return NULL;
+    }
 
     return PyMemoryView_FromObjectAndFlags(self, Py_SAFE_DOWNCAST(flags, Py_ssize_t, int));
 }

From 8502b98121d174f2c12afdb2b06f46fa17a58455 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 4 May 2023 06:17:05 -0700
Subject: [PATCH 34/35] Remove tp_new

---
 Objects/typeobject.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 500e3d782a3eea..456b10ee01d6bc 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8996,7 +8996,6 @@ PyTypeObject _PyBufferWrapper_Type = {
     .tp_name = "_buffer_wrapper",
     .tp_basicsize = sizeof(PyBufferWrapper),
     .tp_alloc = PyType_GenericAlloc,
-    .tp_new = PyType_GenericNew,
     .tp_free = PyObject_GC_Del,
     .tp_traverse = (traverseproc)bufferwrapper_traverse,
     .tp_dealloc = bufferwrapper_dealloc,

From b51465fb3065aa581113c884c49de604aeaeeae9 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Thu, 4 May 2023 06:21:32 -0700
Subject: [PATCH 35/35] regen-all

---
 Include/internal/pycore_global_objects_fini_generated.h | 1 -
 Include/internal/pycore_global_strings.h                | 1 -
 Include/internal/pycore_runtime_init_generated.h        | 1 -
 Include/internal/pycore_unicodeobject_generated.h       | 3 ---
 4 files changed, 6 deletions(-)

diff --git a/Include/internal/pycore_global_objects_fini_generated.h b/Include/internal/pycore_global_objects_fini_generated.h
index 9d97da01d338e5..9377fd8526e3a2 100644
--- a/Include/internal/pycore_global_objects_fini_generated.h
+++ b/Include/internal/pycore_global_objects_fini_generated.h
@@ -749,7 +749,6 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_finalizing));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_find_and_load));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_fix_up_module));
-    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_flags));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_flags_));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_get_sourcefile));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(_handle_fromlist));
diff --git a/Include/internal/pycore_global_strings.h b/Include/internal/pycore_global_strings.h
index f7dc0010316813..ed9b2bb44ddffc 100644
--- a/Include/internal/pycore_global_strings.h
+++ b/Include/internal/pycore_global_strings.h
@@ -237,7 +237,6 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(_finalizing)
         STRUCT_FOR_ID(_find_and_load)
         STRUCT_FOR_ID(_fix_up_module)
-        STRUCT_FOR_ID(_flags)
         STRUCT_FOR_ID(_flags_)
         STRUCT_FOR_ID(_get_sourcefile)
         STRUCT_FOR_ID(_handle_fromlist)
diff --git a/Include/internal/pycore_runtime_init_generated.h b/Include/internal/pycore_runtime_init_generated.h
index c7cd83807b7cb4..6ade8fb6eade03 100644
--- a/Include/internal/pycore_runtime_init_generated.h
+++ b/Include/internal/pycore_runtime_init_generated.h
@@ -743,7 +743,6 @@ extern "C" {
     INIT_ID(_finalizing), \
     INIT_ID(_find_and_load), \
     INIT_ID(_fix_up_module), \
-    INIT_ID(_flags), \
     INIT_ID(_flags_), \
     INIT_ID(_get_sourcefile), \
     INIT_ID(_handle_fromlist), \
diff --git a/Include/internal/pycore_unicodeobject_generated.h b/Include/internal/pycore_unicodeobject_generated.h
index 118fd30adcd94d..0b33ea187e60ff 100644
--- a/Include/internal/pycore_unicodeobject_generated.h
+++ b/Include/internal/pycore_unicodeobject_generated.h
@@ -564,9 +564,6 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(_fix_up_module);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
-    string = &_Py_ID(_flags);
-    assert(_PyUnicode_CheckConsistency(string, 1));
-    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(_flags_);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);

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