Minor change to LOAD_ATTR Opcode in 3.13 not documented

Documentation

The order that items are pushed to the stack by LOAD_ATTR changed in 3.13, but this is not mentioned in the dis module documentation for the LOAD_ATTR Opcode.

Further Details

For the LOAD_ATTR Opcode, the following change from 3.12 is documented

Changed in version 3.12: If the low bit of namei is set, then a NULL or self is pushed to the stack before the attribute or unbound method respectively.

And this can be seen in frameobject.c: https://github.com/python/cpython/blob/3.12/Objects/frameobject.c#L422 where NULL is pushed before Object.

However, in 3.13 this has changed, presumably due to changes to the CALL Opcode;

Changed in version 3.13: The callable now always appears at the same position on the stack.

And for LOAD_ATTR the NULL is now pushed to the stack after the attribute or unbound method.

This ordering change can be seen in frameobject.c for 3.13: https://github.com/python/cpython/blob/3.13/Objects/frameobject.c#L1280 where Object is now pushed before NULL.

Suggested Resolution

My suggestion would be adding something like this to the LOAD_ATTR documentation;

Changed in version 3.13: When the low bit of namei is set, NULL or self is pushed to the stack after the attribute or unbound method respectively.

Linked PRs

• gh-138631

Python 3.13 の dis モジュールのドキュメントにある LOAD_ATTR の項目から始め、issue でリンクされている 3.12 と 3.13 の frameobject.c の箇所とその文言を比較してください。変更を加える前に、リンクされている PR gh-138631 を確認してください。3.13 のスタック順序の変更が正確に記録されれば、ドキュメントは完了です。