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Jeong, YunWon
c603eb7c9a
* Implement PEP 688 __buffer__ and __release_buffer__ A Python class could not export a buffer: the slot machinery had no bf_getbuffer or bf_releasebuffer, and every consumer acquired buffers as PyBUF_FULL_RO through a module of PyBUF_* constants. Add both slots. PyBuffer::release now runs a Python __release_buffer__ before the exporter's own release, once per acquisition, which PyBuffer tracks with an `acquired` flag that clones do not inherit. An export made by a Python __buffer__ is held by a _buffer_wrapper payload that counts its exports and drops the returned memoryview with the last one, and the view handed to __release_buffer__ is a _buffer_window that owns no export, so releasing it inside the hook is inert instead of re-entering it. Replace the PyBUF_* constants with a BufferFlags bitflags type whose composite requests are supersets of the simpler ones, so `contains` answers the REQ_* questions, and pass the request to PyBuffer::from_object. Each consumer now asks for what its counterpart asks for: y* arguments for SIMPLE, w* for WRITABLE, BytesIO.write for CONTIG_RO, bytes(), bytearray() and memoryview() for FULL_RO. memoryview checks the request in memory_getbuf, and array.array and mmap.mmap expose __release_buffer__. Test buffer support with PyObject::check_buffer (PyObject_CheckBuffer) instead of attempting an acquisition, so an exception raised by __buffer__ is no longer reported as the object not being bytes-like, and a __buffer__ with side effects runs once. PyBytesInner becomes a y* conversion as a result: bytes and bytearray methods no longer accept iterables of ints, and find, index, count and __contains__ take the arguments parse_args_finds_byte and bytes_contains describe. A view exports its start offset in the descriptor rather than in its window, which fixes a panic when collecting from a negative-stride view. BytesIO.write rechecks closed after acquiring its buffer, which __buffer__ can close in between. Assisted-by: Claude Code:claude-opus-5 * Rework the buffer protocol around managed exports and view offsets Give `PyBuffer` the `_PyManagedBufferObject` shape: one `bf_getbuffer` acquisition is shared by every handle taken from it, cloning takes another share instead of re-acquiring, and the exporter's release runs once when the last share goes away. Remove `retain`, the unsafe `drop_without_release`, the three `impl Drop`s and the `ManuallyDrop` that stood in for this. Add `abort_acquisition` so a failed request does not run `bf_releasebuffer`. Move the view start into `BufferDescriptor::offset`, the `Py_buffer.buf` analogue, and drop the separate `start` fields on `PyMemoryView` and `PyBufferWrapper`. Slicing goes through `SaturatedSlice::adjust_indices_start`, which reproduces `PySlice_AdjustIndices` and keeps the adjusted start. Fix `zip_eq` to take its contiguous fast path only when both last dimensions are contiguous, and make `for_each_segment` and `zip_eq` handle zero-length and zero-dimensional views. Add `BufferDescriptor::projected` so a request without `PyBUF_ND`, `PyBUF_STRIDES` or `PyBUF_FORMAT` receives a correspondingly reduced descriptor, and reject a request without `PyBUF_INDIRECT` against an exporter that has suboffsets. Copy the source first in `memoryview` slice assignment when both sides reach the same root exporter. Hold the export across the resize in `bytearray.extend`, take `y*` in `marshal.loads`, stop probing the buffer protocol in `FsPath`, rewrite `ord` over the concrete string types, fold `array`'s buffer slot into one `slot_as_buffer`, take `w*`/`y*` in `_overlapped`, and thread the new `offset` field through the `_ctypes` descriptors. Assisted-by: Claude * Re-check a memoryview after a conversion and tighten cast and release `pack_single` and `unpack_single` addressed the buffer with a position taken before `__index__` ran, so releasing the view from that conversion read or wrote outside the exporter's storage, panicking when it had also shrunk. Check the released flag again once the conversion is done, as `CHECK_RELEASED_AGAIN` does. Reject a cast to a format that is not a single native format character with an optional `@` in front of it. An empty format reached a division by its item size of zero. get_native_fmtchar Report a second `__release_buffer__` on the same view as a `ValueError` rather than accepting it, and check that the view belongs to the object first; the silent case is a view that exports nothing. wrap_releasebuffer Compare against another memoryview by reading its view where it lies instead of acquiring a buffer from it, so the restricted view handed to `__release_buffer__` compares equal rather than unequal in one direction only. memory_richcompare Name the type in the unraisable an exception from `__release_buffer__` reports, as `releasebuffer_call_python` does, instead of reporting the exporter object. Assisted-by: Claude * Re-check the destination of a memoryview slice assignment Acquiring the source runs `__buffer__`, which can release the destination view, so check the released flag again once the source is in hand and before the structures are compared, as `copy_single` does. Build the sliced destination as a view that counts as no export, the way a `Py_buffer dest = *view` copy does. Holding one kept the exporter unresizable for the length of the assignment, so a source that released the view and then resized the exporter met a `BufferError` instead of the assignment reporting the released view. Assisted-by: Claude * Answer the memoryview contiguity getsets with the layout `f_contiguous` reported the row-major answer for one dimension and False for any more, so a view laid out both ways, such as one of shape (1, 8), reported False while `check_buffer_request` accepted a `F_CONTIGUOUS` request on it. `contiguous` answered row-major order alone. Move the Fortran-order test from `PyMemoryView` to `BufferDescriptor`, next to the row-major one it differs from only in iteration order, and answer all three getsets with it. Assisted-by: Claude