importing peft with an old version of bitsandbytes causes an exception

[glerzing]

System Info

Importing peft with the bitsandbytes version "0.39.1" works. But when importing peft with the version "0.38.1", I get an exception : AttributeError: module 'bitsandbytes.nn' has no attribute 'Linear4bit'.

Indeed, the class SVDLinear4bit should be defined only if is_bnb_4bit_available(), not just if is_bnb_available().

Who can help?

No response

Information

• The official example scripts
• My own modified scripts

Tasks

• An officially supported task in the examples folder
• My own task or dataset (give details below)

Reproduction

in a notebook :
!pip install 'bitsandbytes==0.38.1'
import peft

Expected behavior

no exception

[glerzing]

@younesbelkada This issue seems important if you plan a new release.

[younesbelkada]

thanks for the ping @glerzing
Did #605 not fixed the issue? can you confirm you get that even with the main branch of PEFT?
That PR introduced a stronger check, and should be using the is_bnb_4bit_available method:

peft/src/peft/tuners/adalora.py

Line 11 in f5352f0

from ..import_utils import is_bnb_4bit_available, is_bnb_available

[glerzing]

Yes, I confirm. And I made a PR here : #646

[younesbelkada]

Thanks a lot @glerzing
Merged #646