Use _cast_input_dtype in poly Linear.forward#3177
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Chessing234 wants to merge 1 commit intohuggingface:mainfrom
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Use _cast_input_dtype in poly Linear.forward#3177Chessing234 wants to merge 1 commit intohuggingface:mainfrom
Chessing234 wants to merge 1 commit intohuggingface:mainfrom
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The raw x.to(A.dtype) cast bypasses the disable_lora_input_dtype_casting context manager. Switch to the BaseTunerLayer._cast_input_dtype helper so poly respects the same casting controls as other tuners (fourierft, vera, etc.).
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@Chessing234 Thanks for the PR. Could you please check all PEFT methods for the same pattern and bundle all changes into a single PR instead of submitting one for each PEFT method individually? Thanks. |
This was referenced May 2, 2026
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Bug
poly.Linear.forwardcasts the input with a rawx.to(A.dtype)instead ofself._cast_input_dtype(...), bypassing thedisable_lora_input_dtype_castingcontext manager.
Root cause
BaseTunerLayerexposes_cast_input_dtype, which respects the module-levelflag for disabling input dtype casting. Most tuners use that helper, but
poly/layer.pystill uses the raw.to()call.Why the fix is correct
PolyLayerinherits fromBaseTunerLayer, soself._cast_input_dtypeisavailable on the
Linearsubclass.this brings poly in line with those tuners.
performs the same cast).
Change
src/peft/tuners/poly/layer.py:x = x.to(A.dtype)→x = self._cast_input_dtype(x, A.dtype).