fix(quantisation): QuantoLoraConv2d cannot be constructed (update_layer missing use_dora)

[Anai-Guo]

Problem

QuantoLoraConv2d cannot be constructed. It defines its own update_layer with use_dora as a required positional parameter:

def update_layer(
    self, adapter_name, r, lora_alpha, lora_dropout, init_lora_weights, use_rslora, use_dora,
):

but __init__ calls it with six arguments (peft_workarounds.py:187):

self.update_layer(adapter_name, r, lora_alpha, lora_dropout, init_lora_weights, use_rslora)

TypeError: update_layer() missing 1 required positional argument: 'use_dora'

This is not a dead path: QuantoLoraConv2d is the QConv2d entry in custom_module_mapping and is instantiated by dispatch_default, so quanto LoRA on any model with Conv2d layers fails during module replacement.

Why use_dora, specifically

Its sibling QuantoLoraLinear calls update_layer with the same six arguments and is fine, because it does not define its own update_layer — it inherits peft's LoraLayer.update_layer, where use_dora has a default. QuantoLoraConv2d overrides the method without a default, so the same six-argument call no longer binds. That asymmetry is the whole bug.

use_dora is already a parameter of QuantoLoraConv2d.__init__ (and is guarded to False two lines above), and update_layer genuinely consumes it:

if use_dora:
    self.dora_init(adapter_name)
    self.use_dora[adapter_name] = True
else:
    self.use_dora[adapter_name] = False

so today the self.use_dora[adapter_name] = False bookkeeping never runs either. Passing the parameter through is what the method was written to receive.

Verification

Both self.update_layer(...) call sites in the file were replayed against the update_layer resolved for their own class, using ast + inspect.Signature.bind (parse only — nothing imported, no torch or quanto needed):

                                                                     BEFORE
QuantoLoraLinear  line  69  self.update_layer(6 args)  [inherited from peft LoraLayer]
    -> skipped: callee is peft's LoraLayer.update_layer

QuantoLoraConv2d  line 187  self.update_layer(6 args)  [own def in QuantoLoraConv2d]
    def update_layer(adapter_name, r, lora_alpha, lora_dropout, init_lora_weights, use_rslora, use_dora)
    -> TypeError: missing a required argument: 'use_dora'

                                                                     AFTER
QuantoLoraConv2d  line 187  self.update_layer(7 args)  [own def in QuantoLoraConv2d]
    -> OK   adapter_name=adapter_name, r=r, lora_alpha=lora_alpha, lora_dropout=lora_dropout,
            init_lora_weights=init_lora_weights, use_rslora=use_rslora, use_dora=use_dora

Formatting checked with the repo's pinned hook — black 24.8.0 --line-length=125 (from .pre-commit-config.yaml) reports the file unchanged both before and after. The new line is 109 characters, within the 125 limit, and flake8 runs with E501 in --extend-ignore regardless.

Net diff: +1 / −1.

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