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mmap.resize() can raise SystemError #138205
Description
Activity
This also happens on MacOSX 15.1, M4 pro
There was other improper use of
SystemErrorin themmapmodule: #7381.I'd like to just remove the method on platforms which doesn't support it for consistent reasons, just like the
madvisemethod is not exist on platforms which doesn't support it.- added a commit that references this issue
on Sep 6, 2025 Since this is a very old behavior, it is not worth to backport the change.
- added a commit that references this issue
on Jan 5, 2026
Bug report
On Posix platforms without mremap() (FreeBSD, OpenBSD, NetBSD, OpenIndiana)
mmap.resize()raises SystemError.SystemError should only be raised in case of the misuse of the C API or breaking internal consistency of the Python core. It is one step away from a segmentation fault or undefined behavior. If some function cannot be implemented, it should either do not exist (causing AttributeError) or raise more appropriate exception when called, like NotImplemenedError, or OSError(ENOTSUP), or simply RuntimeError.
Linked PRs
mmap.mmap.resizein "Porting to Python 3.15" notes #143440