Transformers 4.39.0 has breaking change on torch compatibility.

[xkszltl]

System Info

torch 1.13 + transformers 4.39.0

Description

torch.optim.LRScheduler was only exposed in torch 2:

• Publicly expose _LRScheduler to LRScheduler pytorch/pytorch#88503

Previously it was called _LRScheduler in torch 1.

This recent PR included in 4.39.0 imports it and lead to a hard requirement on torch 2:

• FEAT / Optim: Add GaLore optimizer #29588

FYI @younesbelkada

This issue is captured by our CI where we have dependency on torch 1.

Expected behavior

Suggest to check on version or API availability before use.
Given it's only a visibility change, a transparent fallback/re-route would be ideal.

[ArthurZucker]

This is a duplicate of #29847, I'll push something asap and do a patch release. FYI @LysandreJik and @amyeroberts