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[3.15] gh-159739: Handle overlapping buffers in struct.pack_into (GH-159985) - #160101
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…onGH-159985) `struct.pack_into()` can use the same bytearray as both the destination and an `s` or `p` value. The copy then passes overlapping regions to `memcpy`, which is undefined in C and can produce platform-dependent results or a sanitizer abort. `memmove` makes the overlapping copy defined. (cherry picked from commit 31a7d99) Co-authored-by: Jelle Zijlstra <jelle@openai.com>
This was referenced Oct 21, 2026
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struct.pack_into() can use the same bytearray as both the destination and an s or p value. The copy then passes overlapping regions to memcpy, which is undefined in C and can produce platform-dependent results or a sanitizer abort. memmove makes the overlapping copy defined.
(cherry picked from commit 31a7d99)
Co-authored-by: Jelle Zijlstra jelle@openai.com