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94 changes: 78 additions & 16 deletions src/diffusers/loaders/lora_conversion_utils.py
Original file line number Diff line number Diff line change
Expand Up @@ -2519,6 +2519,13 @@ def normalize_out_key(k: str) -> str:
if has_default:
state_dict = {k.replace("default.", ""): v for k, v in state_dict.items()}

# Normalize ZImage-specific dot-separated module names to underscore form so they
# match the diffusers model parameter names (context_refiner, noise_refiner).
state_dict = {
k.replace("context.refiner.", "context_refiner.").replace("noise.refiner.", "noise_refiner."): v
for k, v in state_dict.items()
}

converted_state_dict = {}
all_keys = list(state_dict.keys())
down_key = ".lora_down.weight"
Expand All @@ -2529,19 +2536,18 @@ def normalize_out_key(k: str) -> str:
has_non_diffusers_lora_id = any(down_key in k or up_key in k for k in all_keys)
has_diffusers_lora_id = any(a_key in k or b_key in k for k in all_keys)

if has_non_diffusers_lora_id:

def get_alpha_scales(down_weight, alpha_key):
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Just moving it out of the if block since it can be generally used.

rank = down_weight.shape[0]
alpha = state_dict.pop(alpha_key).item()
scale = alpha / rank # LoRA is scaled by 'alpha / rank' in forward pass, so we need to scale it back here
scale_down = scale
scale_up = 1.0
while scale_down * 2 < scale_up:
scale_down *= 2
scale_up /= 2
return scale_down, scale_up
def get_alpha_scales(down_weight, alpha_key):
rank = down_weight.shape[0]
alpha = state_dict.pop(alpha_key).item()
scale = alpha / rank # LoRA is scaled by 'alpha / rank' in forward pass, so we need to scale it back here
scale_down = scale
scale_up = 1.0
while scale_down * 2 < scale_up:
scale_down *= 2
scale_up /= 2
return scale_down, scale_up

if has_non_diffusers_lora_id:
for k in all_keys:
if k.endswith(down_key):
diffusers_down_key = k.replace(down_key, ".lora_A.weight")
Expand All @@ -2554,13 +2560,69 @@ def get_alpha_scales(down_weight, alpha_key):
converted_state_dict[diffusers_down_key] = down_weight * scale_down
converted_state_dict[diffusers_up_key] = up_weight * scale_up

# Already in diffusers format (lora_A/lora_B), just pop
# Already in diffusers format (lora_A/lora_B), apply alpha scaling and pop.
elif has_diffusers_lora_id:
for k in all_keys:
if a_key in k or b_key in k:
converted_state_dict[k] = state_dict.pop(k)
elif ".alpha" in k:
if k.endswith(a_key):
diffusers_up_key = k.replace(a_key, b_key)
alpha_key = k.replace(a_key, ".alpha")

down_weight = state_dict.pop(k)
up_weight = state_dict.pop(diffusers_up_key)
scale_down, scale_up = get_alpha_scales(down_weight, alpha_key)
converted_state_dict[k] = down_weight * scale_down
converted_state_dict[diffusers_up_key] = up_weight * scale_up

# Handle dot-format LoRA keys: ".lora.down.weight" / ".lora.up.weight".
# Some external ZImage trainers (e.g. Anime-Z) use dots instead of underscores in
# lora weight names and also include redundant keys:
# - "qkv.lora.*" duplicates individual "to.q/k/v.lora.*" keys → skip qkv
# - "out.lora.*" duplicates "to_out.0.lora.*" keys → skip bare out
# - "to.q/k/v.lora.*" → normalise to "to_q/k/v.lora_A/B.weight"
lora_dot_down_key = ".lora.down.weight"
lora_dot_up_key = ".lora.up.weight"
has_lora_dot_format = any(lora_dot_down_key in k for k in state_dict)

if has_lora_dot_format:
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Main additional to support this LoRA checkpoint structure.

dot_keys = list(state_dict.keys())
for k in dot_keys:
if lora_dot_down_key not in k:
continue
if k not in state_dict:
continue # already popped by a prior iteration

base = k[: -len(lora_dot_down_key)]

# Skip combined "qkv" projection — individual to.q/k/v keys are also present.
if base.endswith(".qkv"):
state_dict.pop(k)
state_dict.pop(k.replace(lora_dot_down_key, lora_dot_up_key), None)
state_dict.pop(base + ".alpha", None)
continue

# Skip bare "out.lora.*" — "to_out.0.lora.*" covers the same projection.
if re.search(r"\.out$", base) and ".to_out" not in base:
state_dict.pop(k)
state_dict.pop(k.replace(lora_dot_down_key, lora_dot_up_key), None)
continue

# Normalise "to.q/k/v" → "to_q/k/v" for the diffusers output key.
norm_k = re.sub(
r"\.to\.([qkv])" + re.escape(lora_dot_down_key) + r"$",
r".to_\1" + lora_dot_down_key,
k,
)
norm_base = norm_k[: -len(lora_dot_down_key)]
alpha_key = norm_base + ".alpha"

diffusers_down = norm_k.replace(lora_dot_down_key, ".lora_A.weight")
diffusers_up = norm_k.replace(lora_dot_down_key, ".lora_B.weight")

down_weight = state_dict.pop(k)
up_weight = state_dict.pop(k.replace(lora_dot_down_key, lora_dot_up_key))
scale_down, scale_up = get_alpha_scales(down_weight, alpha_key)
converted_state_dict[diffusers_down] = down_weight * scale_down
converted_state_dict[diffusers_up] = up_weight * scale_up

if len(state_dict) > 0:
raise ValueError(f"`state_dict` should be empty at this point but has {state_dict.keys()=}")
Expand Down
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