z_image model/pipeline review

[hlky]

z_image model/pipeline review

Commit tested: 0f1abc4ae8b0eb2a3b40e82a310507281144c423

Review performed against the repository review rules.

Duplicate search status: checked GitHub Issues/PRs for z_image, affected class names, and failure modes. Duplicates found for Issue 1 and Issue 3; noted below.

Issue 1: ZImageOmniPipeline crashes when guidance_scale=0

Affected code:

diffusers/src/diffusers/pipelines/z_image/pipeline_z_image_omni.py

Lines 579 to 592 in 0f1abc4

	)
	condition_siglip_embeds = [[se.to(self.transformer.dtype) for se in sels] for sels in condition_siglip_embeds]
	if self.do_classifier_free_guidance:
	negative_condition_siglip_embeds = [[se.clone() for se in batch] for batch in condition_siglip_embeds]
	# Repeat prompt_embeds for num_images_per_prompt
	if num_images_per_prompt > 1:
	prompt_embeds = [pe for pe in prompt_embeds for _ in range(num_images_per_prompt)]
	if self.do_classifier_free_guidance and negative_prompt_embeds:
	negative_prompt_embeds = [npe for npe in negative_prompt_embeds for _ in range(num_images_per_prompt)]
	condition_siglip_embeds = [None if sels == [] else sels + [None] for sels in condition_siglip_embeds]
	negative_condition_siglip_embeds = [
	None if sels == [] else sels + [None] for sels in negative_condition_siglip_embeds

Problem:
negative_condition_siglip_embeds is only assigned inside if self.do_classifier_free_guidance, but it is normalized unconditionally immediately after. The public example uses guidance_scale=0.0, so the documented Omni path raises before denoising.

Duplicate:
Already covered by open PR #13527. This is not a new finding.

Impact:
ZImageOmniPipeline(..., guidance_scale=0.0) fails for the documented turbo/no-CFG usage.

Reproduction:

import torch
from diffusers import AutoencoderKL, FlowMatchEulerDiscreteScheduler, ZImageOmniPipeline, ZImageTransformer2DModel

transformer = ZImageTransformer2DModel(
 all_patch_size=(2,), all_f_patch_size=(1,), in_channels=4, dim=16,
 n_layers=1, n_refiner_layers=1, n_heads=2, n_kv_heads=2,
 cap_feat_dim=8, axes_dims=[4, 2, 2], axes_lens=[32, 32, 32],
)
vae = AutoencoderKL(
 in_channels=3, out_channels=3, down_block_types=["DownEncoderBlock2D"], up_block_types=["UpDecoderBlock2D"],
 block_out_channels=[16], layers_per_block=1, latent_channels=4, norm_num_groups=4, sample_size=32,
 scaling_factor=0.3611, shift_factor=0.1159,
)
pipe = ZImageOmniPipeline(FlowMatchEulerDiscreteScheduler(), vae, None, None, transformer, None, None)
pipe(prompt_embeds=[[torch.randn(3, 8)]], height=32, width=32, num_inference_steps=1, guidance_scale=0.0, output_type="latent")

Relevant precedent:
Open duplicate PR: #13527

Suggested fix:

condition_siglip_embeds = [None if sels == [] else sels + [None] for sels in condition_siglip_embeds]
if self.do_classifier_free_guidance:
 negative_condition_siglip_embeds = [
 None if sels == [] else sels + [None] for sels in negative_condition_siglip_embeds
 ]
else:
 negative_condition_siglip_embeds = None

Issue 2: Omni condition-image encoding hard-casts VAE input to bfloat16

Affected code:

diffusers/src/diffusers/pipelines/z_image/pipeline_z_image_omni.py

Lines 293 to 306 in 0f1abc4

	def prepare_image_latents(
	self,
	images: list[torch.Tensor],
	batch_size,
	device,
	dtype,
	):
	image_latents = []
	for image in images:
	image = image.to(device=device, dtype=dtype)
	image_latent = (
	self.vae.encode(image.bfloat16()).latent_dist.mode()[0] - self.vae.config.shift_factor
	) * self.vae.config.scaling_factor
	image_latent = image_latent.unsqueeze(1).to(dtype)

Problem:
prepare_image_latents() calls self.vae.encode(image.bfloat16()) regardless of the VAE dtype. A float32 VAE on CPU receives bf16 inputs with float32 weights and raises a dtype mismatch.

Impact:
Omni image-conditioned generation fails outside the exact bf16 VAE setup. It also violates the dtype/device handling rule by hardcoding a dtype in pipeline runtime code.

Reproduction:

import torch
from diffusers import AutoencoderKL, ZImageOmniPipeline

vae = AutoencoderKL(
 in_channels=3, out_channels=3, down_block_types=["DownEncoderBlock2D"], up_block_types=["UpDecoderBlock2D"],
 block_out_channels=[16], layers_per_block=1, latent_channels=4, norm_num_groups=4, sample_size=32,
 scaling_factor=0.3611, shift_factor=0.1159,
)
pipe = object.__new__(ZImageOmniPipeline)
pipe.vae = vae
pipe.prepare_image_latents([torch.rand(1, 3, 32, 32)], 1, torch.device("cpu"), torch.float32)

Relevant precedent:
Other image-encoding paths convert to the requested/vae dtype before vae.encode, not a fixed bf16 dtype.

Suggested fix:

vae_dtype = self.vae.dtype
image = image.to(device=device, dtype=vae_dtype)
image_latent = (
 self.vae.encode(image).latent_dist.mode()[0] - self.vae.config.shift_factor
) * self.vae.config.scaling_factor
image_latent = image_latent.unsqueeze(1).to(dtype)

Issue 3: ZImageControlNetModel has gradient-checkpointing flag but never initializes it

Affected code:

diffusers/src/diffusers/models/controlnets/controlnet_z_image.py

Lines 433 to 517 in 0f1abc4

	_supports_gradient_checkpointing = True
	@register_to_config
	def __init__(
	self,
	control_layers_places: list[int] = None,
	control_refiner_layers_places: list[int] = None,
	control_in_dim=None,
	add_control_noise_refiner: Literal["control_layers", "control_noise_refiner"] | None = None,
	all_patch_size=(2,),
	all_f_patch_size=(1,),
	dim=3840,
	n_refiner_layers=2,
	n_heads=30,
	n_kv_heads=30,
	norm_eps=1e-5,
	qk_norm=True,
	):
	super().__init__()
	self.control_layers_places = control_layers_places
	self.control_in_dim = control_in_dim
	self.control_refiner_layers_places = control_refiner_layers_places
	self.add_control_noise_refiner = add_control_noise_refiner
	assert 0 in self.control_layers_places
	# control blocks
	self.control_layers = nn.ModuleList(
	[
	ZImageControlTransformerBlock(i, dim, n_heads, n_kv_heads, norm_eps, qk_norm, block_id=i)
	for i in self.control_layers_places
	]
	)
	# control patch embeddings
	all_x_embedder = {}
	for patch_idx, (patch_size, f_patch_size) in enumerate(zip(all_patch_size, all_f_patch_size)):
	x_embedder = nn.Linear(f_patch_size * patch_size * patch_size * self.control_in_dim, dim, bias=True)
	all_x_embedder[f"{patch_size}-{f_patch_size}"] = x_embedder
	self.control_all_x_embedder = nn.ModuleDict(all_x_embedder)
	if self.add_control_noise_refiner == "control_layers":
	self.control_noise_refiner = None
	elif self.add_control_noise_refiner == "control_noise_refiner":
	self.control_noise_refiner = nn.ModuleList(
	[
	ZImageControlTransformerBlock(
	1000 + layer_id,
	dim,
	n_heads,
	n_kv_heads,
	norm_eps,
	qk_norm,
	modulation=True,
	block_id=layer_id,
	)
	for layer_id in range(n_refiner_layers)
	]
	)
	else:
	self.control_noise_refiner = nn.ModuleList(
	[
	ZImageTransformerBlock(
	1000 + layer_id,
	dim,
	n_heads,
	n_kv_heads,
	norm_eps,
	qk_norm,
	modulation=True,
	)
	for layer_id in range(n_refiner_layers)
	]
	)
	self.t_scale: float | None = None
	self.t_embedder: TimestepEmbedder | None = None
	self.all_x_embedder: nn.ModuleDict | None = None
	self.cap_embedder: nn.Sequential | None = None
	self.rope_embedder: RopeEmbedder | None = None
	self.noise_refiner: nn.ModuleList | None = None
	self.context_refiner: nn.ModuleList | None = None
	self.x_pad_token: nn.Parameter | None = None
	self.cap_pad_token: nn.Parameter | None = None

diffusers/src/diffusers/models/controlnets/controlnet_z_image.py

Lines 753 to 833 in 0f1abc4

	if torch.is_grad_enabled() and self.gradient_checkpointing:
	for layer_idx, layer in enumerate(self.noise_refiner):
	x = self._gradient_checkpointing_func(layer, x, x_attn_mask, x_freqs_cis, adaln_input)
	if noise_refiner_block_samples is not None:
	if layer_idx in noise_refiner_block_samples:
	x = x + noise_refiner_block_samples[layer_idx]
	else:
	for layer_idx, layer in enumerate(self.noise_refiner):
	x = layer(x, x_attn_mask, x_freqs_cis, adaln_input)
	if noise_refiner_block_samples is not None:
	if layer_idx in noise_refiner_block_samples:
	x = x + noise_refiner_block_samples[layer_idx]
	# cap embed & refine
	cap_item_seqlens = [len(_) for _ in cap_feats]
	cap_max_item_seqlen = max(cap_item_seqlens)
	cap_feats = torch.cat(cap_feats, dim=0)
	cap_feats = self.cap_embedder(cap_feats)
	cap_feats[torch.cat(cap_inner_pad_mask)] = self.cap_pad_token
	cap_feats = list(cap_feats.split(cap_item_seqlens, dim=0))
	cap_freqs_cis = list(
	self.rope_embedder(torch.cat(cap_pos_ids, dim=0)).split([len(_) for _ in cap_pos_ids], dim=0)
	)
	cap_feats = pad_sequence(cap_feats, batch_first=True, padding_value=0.0)
	cap_freqs_cis = pad_sequence(cap_freqs_cis, batch_first=True, padding_value=0.0)
	# Clarify the length matches to satisfy Dynamo due to "Symbolic Shape Inference" to avoid compilation errors
	cap_freqs_cis = cap_freqs_cis[:, : cap_feats.shape[1]]
	cap_attn_mask = torch.zeros((bsz, cap_max_item_seqlen), dtype=torch.bool, device=device)
	for i, seq_len in enumerate(cap_item_seqlens):
	cap_attn_mask[i, :seq_len] = 1
	if torch.is_grad_enabled() and self.gradient_checkpointing:
	for layer in self.context_refiner:
	cap_feats = self._gradient_checkpointing_func(layer, cap_feats, cap_attn_mask, cap_freqs_cis)
	else:
	for layer in self.context_refiner:
	cap_feats = layer(cap_feats, cap_attn_mask, cap_freqs_cis)
	# unified
	unified = []
	unified_freqs_cis = []
	for i in range(bsz):
	x_len = x_item_seqlens[i]
	cap_len = cap_item_seqlens[i]
	unified.append(torch.cat([x[i][:x_len], cap_feats[i][:cap_len]]))
	unified_freqs_cis.append(torch.cat([x_freqs_cis[i][:x_len], cap_freqs_cis[i][:cap_len]]))
	unified_item_seqlens = [a + b for a, b in zip(cap_item_seqlens, x_item_seqlens)]
	assert unified_item_seqlens == [len(_) for _ in unified]
	unified_max_item_seqlen = max(unified_item_seqlens)
	unified = pad_sequence(unified, batch_first=True, padding_value=0.0)
	unified_freqs_cis = pad_sequence(unified_freqs_cis, batch_first=True, padding_value=0.0)
	unified_attn_mask = torch.zeros((bsz, unified_max_item_seqlen), dtype=torch.bool, device=device)
	for i, seq_len in enumerate(unified_item_seqlens):
	unified_attn_mask[i, :seq_len] = 1
	## ControlNet start
	if not self.add_control_noise_refiner:
	if torch.is_grad_enabled() and self.gradient_checkpointing:
	for layer in self.control_noise_refiner:
	control_context = self._gradient_checkpointing_func(
	layer, control_context, x_attn_mask, x_freqs_cis, adaln_input
	)
	else:
	for layer in self.control_noise_refiner:
	control_context = layer(control_context, x_attn_mask, x_freqs_cis, adaln_input)
	# unified
	control_context_unified = []
	for i in range(bsz):
	x_len = x_item_seqlens[i]
	cap_len = cap_item_seqlens[i]
	control_context_unified.append(torch.cat([control_context[i][:x_len], cap_feats[i][:cap_len]]))
	control_context_unified = pad_sequence(control_context_unified, batch_first=True, padding_value=0.0)
	for layer in self.control_layers:
	if torch.is_grad_enabled() and self.gradient_checkpointing:
	control_context_unified = self._gradient_checkpointing_func(

Problem:
The model sets _supports_gradient_checkpointing = True and branches on self.gradient_checkpointing, but __init__ never sets self.gradient_checkpointing = False.

Duplicate:
Already covered by open PR #13267. This is not a new finding.

Impact:
Direct grad-enabled forward, training, or checkpointing setup fails with AttributeError.

Reproduction:

import torch
from diffusers import ZImageControlNetModel, ZImageTransformer2DModel

transformer = ZImageTransformer2DModel(
 all_patch_size=(2,), all_f_patch_size=(1,), in_channels=4, dim=16,
 n_layers=1, n_refiner_layers=1, n_heads=2, n_kv_heads=2,
 cap_feat_dim=8, axes_dims=[4, 2, 2], axes_lens=[64, 64, 64],
)
controlnet = ZImageControlNetModel(
 control_layers_places=[0], control_refiner_layers_places=[0], control_in_dim=4,
 all_patch_size=(2,), all_f_patch_size=(1,), dim=16, n_refiner_layers=1,
 n_heads=2, n_kv_heads=2,
)
controlnet = ZImageControlNetModel.from_transformer(controlnet, transformer)
controlnet([torch.randn(4, 1, 32, 32)], torch.tensor([0.5]), [torch.randn(3, 8)], [torch.randn(4, 1, 32, 32)])

Relevant precedent:

diffusers/src/diffusers/models/controlnets/controlnet_qwenimage.py

Line 101 in 0f1abc4

self.gradient_checkpointing = False

Suggested fix:

self.gradient_checkpointing = False

Issue 4: ZImageInpaintPipeline.masked_image_latents is accepted but ignored

Affected code:

diffusers/src/diffusers/pipelines/z_image/pipeline_z_image_inpaint.py

Lines 537 to 576 in 0f1abc4

	masked_image_latents: Optional[torch.FloatTensor] = None,
	strength: float = 1.0,
	height: int | None = None,
	width: int | None = None,
	num_inference_steps: int = 50,
	sigmas: list[float] | None = None,
	guidance_scale: float = 5.0,
	cfg_normalization: bool = False,
	cfg_truncation: float = 1.0,
	negative_prompt: Optional[Union[str, List[str]]] = None,
	num_images_per_prompt: Optional[int] = 1,
	generator: torch.Generator | list[torch.Generator] | None = None,
	latents: Optional[torch.FloatTensor] = None,
	prompt_embeds: Optional[List[torch.FloatTensor]] = None,
	negative_prompt_embeds: Optional[List[torch.FloatTensor]] = None,
	output_type: str = "pil",
	return_dict: bool = True,
	joint_attention_kwargs: Optional[Dict[str, Any]] = None,
	callback_on_step_end: Optional[Callable[[int, int, Dict], None]] = None,
	callback_on_step_end_tensor_inputs: List[str] = ["latents"],
	max_sequence_length: int = 512,
	):
	r"""
	Function invoked when calling the pipeline for inpainting.
	Args:
	prompt (`str` or `List[str]`, *optional*):
	The prompt or prompts to guide the image generation. If not defined, one has to pass `prompt_embeds`.
	instead.
	image (`torch.Tensor`, `PIL.Image.Image`, `np.ndarray`, `List[torch.Tensor]`, `List[PIL.Image.Image]`, or `List[np.ndarray]`):
	`Image`, numpy array or tensor representing an image batch to be used as the starting point. For both
	numpy array and pytorch tensor, the expected value range is between `[0, 1]`. If it's a tensor or a
	list of tensors, the expected shape should be `(B, C, H, W)` or `(C, H, W)`. If it is a numpy array or
	a list of arrays, the expected shape should be `(B, H, W, C)` or `(H, W, C)`.
	mask_image (`torch.Tensor`, `PIL.Image.Image`, `np.ndarray`, `List[torch.Tensor]`, `List[PIL.Image.Image]`, or `List[np.ndarray]`):
	`Image`, numpy array or tensor representing a mask image for inpainting. White pixels (value 1) in the
	mask will be inpainted, black pixels (value 0) will be preserved from the original image.
	masked_image_latents (`torch.FloatTensor`, *optional*):
	Pre-encoded masked image latents. If provided, the masked image encoding step will be skipped.
	strength (`float`, *optional*, defaults to 1.0):

diffusers/src/diffusers/pipelines/z_image/pipeline_z_image_inpaint.py

Lines 788 to 797 in 0f1abc4

	if masked_image_latents is None:
	masked_image = init_image * (mask < 0.5)
	else:
	masked_image = None # Will use provided masked_image_latents
	mask, masked_image_latents = self.prepare_mask_latents(
	mask,
	masked_image if masked_image is not None else init_image,
	actual_batch_size,
	height,

Problem:
The public argument says precomputed masked latents skip encoding, but the value is never passed into prepare_mask_latents() and never affects denoising. Different supplied masked_image_latents produce identical outputs.

Impact:
Users cannot actually provide precomputed masked latents, and the callback tensor implies a state value that does not participate in generation.

Reproduction:

import torch
from diffusers import AutoencoderKL, FlowMatchEulerDiscreteScheduler, ZImageInpaintPipeline, ZImageTransformer2DModel

torch.manual_seed(0)
transformer = ZImageTransformer2DModel(
 all_patch_size=(2,), all_f_patch_size=(1,), in_channels=4, dim=16,
 n_layers=1, n_refiner_layers=1, n_heads=2, n_kv_heads=2,
 cap_feat_dim=8, axes_dims=[4, 2, 2], axes_lens=[64, 64, 64],
)
vae = AutoencoderKL(
 in_channels=3, out_channels=3, down_block_types=["DownEncoderBlock2D"], up_block_types=["UpDecoderBlock2D"],
 block_out_channels=[16], layers_per_block=1, latent_channels=4, norm_num_groups=4, sample_size=32,
 scaling_factor=0.3611, shift_factor=0.1159,
)
pipe = ZImageInpaintPipeline(FlowMatchEulerDiscreteScheduler(), vae, None, None, transformer)
pipe.set_progress_bar_config(disable=True)
kwargs = dict(
 prompt_embeds=[torch.randn(3, 8)], image=torch.rand(1, 3, 32, 32), mask_image=torch.ones(1, 1, 32, 32),
 height=32, width=32, num_inference_steps=1, guidance_scale=0.0, output_type="latent",
 latents=torch.randn(1, 4, 32, 32),
)
a = pipe(**kwargs, masked_image_latents=torch.zeros(1, 4, 32, 32), generator=torch.Generator().manual_seed(123)).images
b = pipe(**kwargs, masked_image_latents=torch.randn(1, 4, 32, 32), generator=torch.Generator().manual_seed(123)).images
print(torch.equal(a, b))

Relevant precedent:

diffusers/src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_inpaint.py

Lines 1204 to 1209 in 0f1abc4

	if masked_image_latents is None:
	masked_image = init_image * (mask_condition < 0.5)
	else:
	masked_image = masked_image_latents
	mask, masked_image_latents = self.prepare_mask_latents(

Suggested fix:
If Z-Image inpaint is intended to be latent-blending only, remove or deprecate masked_image_latents and the callback tensor. If it is intended to match SD-style inpaint conditioning, thread the provided tensor through prepare_mask_latents() and into the model input path.

Issue 5: Model dtype rules are violated in shared transformer/controlnet helpers

Affected code:

diffusers/src/diffusers/models/transformers/transformer_z_image.py

Line 65 in 0f1abc4

weight_dtype = self.mlp[0].weight.dtype

diffusers/src/diffusers/models/transformers/transformer_z_image.py

Lines 327 to 332 in 0f1abc4

	def precompute_freqs_cis(dim: list[int], end: list[int], theta: float = 256.0):
	with torch.device("cpu"):
	freqs_cis = []
	for i, (d, e) in enumerate(zip(dim, end)):
	freqs = 1.0 / (theta ** (torch.arange(0, d, 2, dtype=torch.float64, device="cpu") / d))
	timestep = torch.arange(e, device=freqs.device, dtype=torch.float64)

diffusers/src/diffusers/models/controlnets/controlnet_z_image.py

Line 67 in 0f1abc4

weight_dtype = self.mlp[0].weight.dtype

diffusers/src/diffusers/models/controlnets/controlnet_z_image.py

Lines 304 to 309 in 0f1abc4

	def precompute_freqs_cis(dim: list[int], end: list[int], theta: float = 256.0):
	with torch.device("cpu"):
	freqs_cis = []
	for i, (d, e) in enumerate(zip(dim, end)):
	freqs = 1.0 / (theta ** (torch.arange(0, d, 2, dtype=torch.float64, device="cpu") / d))
	timestep = torch.arange(e, device=freqs.device, dtype=torch.float64)

Problem:
TimestepEmbedder.forward() casts by reading self.mlp[0].weight.dtype, and RopeEmbedder.precompute_freqs_cis() unconditionally constructs float64 tensors. Both patterns are explicitly called out in the model review rules.

Impact:
This is fragile for quantized/GGUF/layerwise-casting loads and violates backend portability expectations for MPS/NPU-style environments.

Reproduction:

from pathlib import Path

for path in [
 "src/diffusers/models/transformers/transformer_z_image.py",
 "src/diffusers/models/controlnets/controlnet_z_image.py",
]:
 for i, line in enumerate(Path(path).read_text().splitlines(), 1):
 if "weight.dtype" in line or "torch.float64" in line:
 print(path, i, line.strip())

Relevant precedent:

diffusers/src/diffusers/models/transformers/transformer_flux.py

Lines 508 to 516 in 0f1abc4

	freqs_dtype = torch.float32 if (is_mps or is_npu) else torch.float64
	for i in range(n_axes):
	cos, sin = get_1d_rotary_pos_embed(
	self.axes_dim[i],
	pos[:, i],
	theta=self.theta,
	repeat_interleave_real=True,
	use_real=True,
	freqs_dtype=freqs_dtype,

Suggested fix:
Use float32 for RoPE precompute unless there is measured need for gated float64, and pass the desired activation dtype from the caller into TimestepEmbedder instead of reading parameter storage dtype.

Issue 6: Modular pipeline generated docs still contain TODO placeholders

Affected code:

diffusers/src/diffusers/modular_pipelines/z_image/modular_blocks_z_image.py

Lines 46 to 75 in 0f1abc4

	class ZImageCoreDenoiseStep(SequentialPipelineBlocks):
	"""
	denoise block that takes encoded conditions and runs the denoising process.
	Components:
	transformer (`ZImageTransformer2DModel`) scheduler (`FlowMatchEulerDiscreteScheduler`) guider
	(`ClassifierFreeGuidance`)
	Inputs:
	num_images_per_prompt (`None`, *optional*, defaults to 1):
	TODO: Add description.
	prompt_embeds (`list`):
	Pre-generated text embeddings. Can be generated from text_encoder step.
	negative_prompt_embeds (`list`, *optional*):
	Pre-generated negative text embeddings. Can be generated from text_encoder step.
	height (`int`, *optional*):
	TODO: Add description.
	width (`int`, *optional*):
	TODO: Add description.
	latents (`Tensor | NoneType`, *optional*):
	TODO: Add description.
	generator (`None`, *optional*):
	TODO: Add description.
	num_inference_steps (`None`, *optional*, defaults to 9):
	TODO: Add description.
	sigmas (`None`, *optional*):
	TODO: Add description.
	**denoiser_input_fields (`None`, *optional*):
	The conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.

Problem:
modular_blocks_z_image.py contains many generated TODO: Add description. entries. The modular review rules explicitly require generated modular docstrings to be fixed after running auto-docstring generation.

Impact:
Public modular pipeline docs/API metadata are incomplete for several inputs, including height, width, latents, generator, sigmas, and workflow-specific inputs.

Reproduction:

from pathlib import Path

path = Path("src/diffusers/modular_pipelines/z_image/modular_blocks_z_image.py")
print(sum("TODO: Add description." in line for line in path.read_text().splitlines()))

Relevant precedent:
.ai/modular.md conversion checklist requires running utils/modular_auto_docstring.py --fix_and_overwrite and resolving TODO placeholders.

Suggested fix:
Add accurate InputParam descriptions/types for the missing fields, rerun python utils/modular_auto_docstring.py --fix_and_overwrite, and verify no generated TODOs remain.

Issue 7: Coverage gaps: no slow tests, no ControlNet/Omni pipeline tests, and docs omit public variants

Affected code:

diffusers/src/diffusers/pipelines/z_image/__init__.py

Lines 24 to 30 in 0f1abc4

	_import_structure["pipeline_output"] = ["ZImagePipelineOutput"]
	_import_structure["pipeline_z_image"] = ["ZImagePipeline"]
	_import_structure["pipeline_z_image_controlnet"] = ["ZImageControlNetPipeline"]
	_import_structure["pipeline_z_image_controlnet_inpaint"] = ["ZImageControlNetInpaintPipeline"]
	_import_structure["pipeline_z_image_img2img"] = ["ZImageImg2ImgPipeline"]
	_import_structure["pipeline_z_image_inpaint"] = ["ZImageInpaintPipeline"]
	_import_structure["pipeline_z_image_omni"] = ["ZImageOmniPipeline"]

diffusers/tests/pipelines/z_image/test_z_image.py

Line 45 in 0f1abc4

class ZImagePipelineFastTests(PipelineTesterMixin, unittest.TestCase):

diffusers/docs/source/en/api/pipelines/z_image.md

Lines 91 to 105 in 0f1abc4

	## ZImagePipeline
	[[autodoc]] ZImagePipeline
	- all
	- __call__
	## ZImageImg2ImgPipeline
	[[autodoc]] ZImageImg2ImgPipeline
	- all
	- __call__
	## ZImageInpaintPipeline
	[[autodoc]] ZImageInpaintPipeline

Problem:
The package exports ZImageControlNetPipeline, ZImageControlNetInpaintPipeline, and ZImageOmniPipeline, but tests/pipelines/z_image/ only has fast tests for text2img/img2img/inpaint. There are no z_image slow tests. The pipeline docs only autodoc the three non-ControlNet/non-Omni pipelines.

Impact:
The exact Omni no-CFG crash and ControlNet checkpointing issue above are not covered by pipeline tests. Real-checkpoint regressions are also unguarded.

Reproduction:

from pathlib import Path

test_text = "\n".join(p.read_text() for p in Path("tests").rglob("*z_image*.py"))
docs = Path("docs/source/en/api/pipelines/z_image.md").read_text()

print("@slow" in test_text or "slow(" in test_text)
print("ZImageOmniPipeline" in test_text, "ZImageControlNetPipeline" in test_text)
print("ZImageOmniPipeline" in docs, "ZImageControlNetPipeline" in docs)

Relevant precedent:
Most mature pipeline families include at least one @slow real-checkpoint smoke test for public pipelines, plus fast tests for every exported variant.

Suggested fix:
Add fast tests for Omni and both ControlNet pipelines using tiny fixtures, add at least one slow real-checkpoint smoke test for the z_image family, and add autodoc sections for the public ControlNet and Omni pipelines.

Verification performed:

• Minimal .venv snippets confirmed Issues 1-4.
• tests/modular_pipelines/z_image/test_modular_pipeline_z_image.py -q: 14 passed.
• Pipeline fast tests could not be collected in this .venv because the installed PyTorch build lacks torch._C._distributed_c10d, imported via shared training test utilities.