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_io.BytesIO.getbuffer(): unshare_buffer: Assertion `self->exports == 0' failed #111174
Description
Crash report
What happened?
import io
f = io.BytesIO()
a = f.getbuffer()
b = f.getbuffer()Output:
python: ./Modules/_io/bytesio.c:112: unshare_buffer: Assertion `self->exports == 0' failed.
Aborted (core dumped)
Reproduced on 3.8 and 3.11-3.13.
CPython versions tested on:
3.8, 3.11, 3.12, CPython main branch
Operating systems tested on:
Linux
Output from running 'python -VV' on the command line:
Python 3.13.0a1+ (heads/main:11312eae6e, Oct 22 2023, 02:44:38) [GCC 10.2.1 20210110]
Activity
Eclips4 commentedon Oct 22, 2023
cc @serhiy-storchaka as author of
unshare_bufferfunctionchgnrdv commentedon Oct 22, 2023
Docs for
BytesIO.getbuffersay that it returns readable and writable view over the buffer of correspondingBytesIOobject without copying the contents of this buffer, and that mutating the view updates the buffer it wraps. Shouldbytesiobuf_getbuffercallunshare_bufferat all in this case, or I am missing something?pythongh-111174: Fix crash in getbuffer() called repeatedly for empty…
serhiy-storchaka commentedon Oct 23, 2023
The cause is that empty bytes objects are shared across the interpreter. So
Py_REFCNT(self->buf) > 1even for just createdself->bufif it is empty.gh-111174: Fix crash in getbuffer() called repeatedly for empty Bytes…
pythongh-111174: Fix crash in getbuffer() called repeatedly for empty…
pythongh-111174: Fix crash in getbuffer() called repeatedly for empty…
[3.11] gh-111174: Fix crash in getbuffer() called repeatedly for empt…
[3.12] gh-111174: Fix crash in getbuffer() called repeatedly for empt…
Eclips4 commentedon Oct 25, 2023
Thanks Radislav for the report and Serhiy for the fix!
pythongh-111174: Fix crash in getbuffer() called repeatedly for empty…
pythongh-111174: Fix crash in getbuffer() called repeatedly for empty…