Loading an object containing a matrix that was saved in Python 2 sage

[Paul Leopardi]

Hello,

I am currently trying to convert my Boolean-Cayley-graphs project from Python 2 to Python 3 Sage. https://github.com/penguian/Boolean-Cayley-graphs/tree/23-port-to-python-3

I have succeeded in converting the code, but am having a tough time trying to load objects that were saved by my previous Python 2-based code. These objects contain matrices as members.What do I need to do to be able to load these objects?

As far as I can tell, load(...,encoding='latin-1') doesn't work with a dict containing a matrix but load(...,encoding='bytes') does. See the attachment.

Thanks!

[Paul Leopardi]

See also https://groups.google.com/g/sage-support/c/3WKui-LojKs/m/DgEPBGF3AQAJ and https://trac.sagemath.org/ticket/28444

[Nils Bruin]

Yes, we know how to fix it and it's not complicated: if "bytes" is expected in a pickle and a "str" is found, we should assume it represents the bytes-object via latin-1. It's come up in matrices elsewhere and we should just make this change. We've already determined that "encoding='bytes'" is a lot harder to get to work.

Please open a ticket. Fixing this should save a LOT of pickles.

[Paul Leopardi]

Done. https://trac.sagemath.org/ticket/30402

[Paul Leopardi]

I have about 6 TB of saved Sage objects that I would like to recover, so am interested in testing the fix.