Skip to content

gh-140868: Don't rely on undefined left shift behavior in assert #140869

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Nov 1, 2025
Merged

gh-140868: Don't rely on undefined left shift behavior in assert #140869

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion Include/internal/pycore_stackref.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -403,7 +403,8 @@ PyStackRef_IsTaggedInt(_PyStackRef i)
static inline _PyStackRef
PyStackRef_TagInt(intptr_t i)
{
assert(Py_ARITHMETIC_RIGHT_SHIFT(intptr_t, (i << Py_TAGGED_SHIFT), Py_TAGGED_SHIFT) == i);
assert(Py_ARITHMETIC_RIGHT_SHIFT(intptr_t, (intptr_t)(((uintptr_t)i) << Py_TAGGED_SHIFT),
Copy link
Contributor

@sergey-miryanov sergey-miryanov Nov 1, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Nice catch! 👍

Copy link
Contributor Author

@DinoV DinoV Nov 1, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

All I did was run the build in our default settings at work! 😀

Py_TAGGED_SHIFT) == i);
return (_PyStackRef){ .bits = ((((uintptr_t)i) << Py_TAGGED_SHIFT) | Py_INT_TAG) };
}

Expand Down
Loading