Z-Image uses CFG formula `pred = pos + scale * (pos - neg)` where
`guidance_scale = 0` means no guidance. The threshold should be `> 0`
instead of `> 1` to match this formula.
Co-authored-by: Hezlich2 <typretypre@gmail.com>
* fix: graceful fallback when attention backends fail to import
## Problem
External attention backends (flash_attn, xformers, sageattention, etc.) may be
installed but fail to import at runtime due to ABI mismatches. For example,
when `flash_attn` is compiled against PyTorch 2.4 but used with PyTorch 2.8,
the import fails with:
```
OSError: .../flash_attn_2_cuda.cpython-311-x86_64-linux-gnu.so: undefined symbol: _ZN3c104cuda9SetDeviceEab
```
The current code uses `importlib.util.find_spec()` to check if packages exist,
but this only verifies the package is installed—not that it can actually be
imported. When the import fails, diffusers crashes instead of falling back to
native PyTorch attention.
## Solution
Wrap all external attention backend imports in try-except blocks that catch
`ImportError` and `OSError`. On failure:
1. Log a warning message explaining the issue
2. Set the corresponding `_CAN_USE_*` flag to `False`
3. Set the imported functions to `None`
This allows diffusers to gracefully degrade to PyTorch's native SDPA
(scaled_dot_product_attention) instead of crashing.
## Affected backends
- flash_attn (Flash Attention)
- flash_attn_3 (Flash Attention 3)
- aiter (AMD Instinct)
- sageattention (SageAttention)
- flex_attention (PyTorch Flex Attention)
- torch_npu (Huawei NPU)
- torch_xla (TPU/XLA)
- xformers (Meta xFormers)
## Testing
Tested with PyTorch 2.8.0 and flash_attn 2.7.4.post1 (compiled for PyTorch 2.4).
Before: crashes on import. After: logs warning and uses native attention.
* address review: use single logger and catch RuntimeError
- Move logger to module level instead of creating per-backend loggers
- Add RuntimeError to exception list alongside ImportError and OSError
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* Apply style fixes
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
* switch to transformers main again./
* more
* up
* up
* fix group offloading.
* attributes
* up
* up
* tie embedding issue.
* fix t5 stuff for more.
* matrix configuration to see differences between 4.57.3 and main failures.
* change qwen expected slice because of how init is handled in v5.
* same stuff.
* up
* up
* Revert "up"
This reverts commit 515dd06db5.
* Revert "up"
This reverts commit 5274ffdd7f.
* up
* up
* fix with peft_format.
* just keep main for easier debugging.
* remove torchvision.
* empty
* up
* up with skyreelsv2 fixes.
* fix skyreels type annotation.
* up
* up
* fix variant loading issues.
* more fixes.
* fix dduf
* fix
* fix
* fix
* more fixes
* fixes
* up
* up
* fix dduf test
* up
* more
* update
* hopefully ,final?
* one last breath
* always install from main
* up
* audioldm tests
* up
* fix PRX tests.
* up
* kandinsky fixes
* qwen fixes.
* prx
* hidream
[gguf] Convert to plain tensor earlier in dequantize_gguf_tensor
Once dequantize_gguf_tensor fetches the quant_type attributed from the
GGUFParamter tensor subclass, there is no further need of running the
actual dequantize operations on the Tensor subclass, we can just convert
to plain tensor right away.
This not only makes PyTorch eager faster, but reduces torch.compile
tracer compile time from 36 seconds to 10 seconds, because there is lot
less code to trace now.
* Guard ftfy import with is_ftfy_available
* Remove xfail for PRX pipeline tests as they appear to work on transformers>4.57.1
* make style and make quality
* support device type device_maps to work with offloading.
* add tests.
* fix tests
* skip tests where it's not supported.
* empty
* up
* up
* fix allegro.
* up
* up up
* update outputs
* style
* add modular_auto_docstring!
* more auto docstring
* style
* up up up
* more more
* up
* address feedbacks
* add TODO in the description for empty docstring
* refactor based on dhruv's feedback: remove the class method
* add template method
* up
* up up up
* apply auto docstring
* make style
* rmove space in make docstring
* Apply suggestions from code review
* revert change in z
* fix
* Apply style fixes
* include auto-docstring check in the modular ci. (#13004)
* initial support: workflow
* up up
* treeat loop sequential pipeline blocks as leaf
* update qwen image docstring note
* add workflow support for sdxl
* add a test suit
* add test for qwen-image
* refactor flux a bit, seperate modular_blocks into modular_blocks_flux and modular_blocks_flux_kontext + support workflow
* refactor flux2: seperate blocks for klein_base + workflow
* qwen: remove import support for stuff other than the default blocks
* add workflow support for wan
* sdxl: remove some imports:
* refactor z
* update flux2 auto core denoise
* add workflow test for z and flux2
* Apply suggestions from code review
* Apply suggestions from code review
* add test for flux
* add workflow test for flux
* add test for flux-klein
* sdxl: modular_blocks.py -> modular_blocks_stable_diffusion_xl.py
* style
* up
* add auto docstring
* workflow_names -> available_workflows
* fix workflow test for klein base
* Apply suggestions from code review
Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>
* fix workflow tests
* qwen: edit -> image_conditioned to be consistent with flux kontext/2 such
* remove Optional
* update type hints
* update guider update_components
* fix more
* update docstring auto again
---------
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
Co-authored-by: yiyi@huggingface.co <yiyi@ip-26-0-160-103.ec2.internal>
Co-authored-by: yiyi@huggingface.co <yiyi@ip-26-0-161-123.ec2.internal>
Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>
* drop python 3.8
* remove list, tuple, dict from typing
* fold Unions into |
* up
* fix a bunch and please me.
* up
* up
* up
* up
* up
* up
* enforce 3.10.0.
* up
* up
* up
* up
* up
* up
* up
* up
* Update setup.py
Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>
* up.
* python 3.10.
* ifx
* up
* up
* up
* up
* final
* up
* fix typing utils.
* up
* up
* up
* up
* up
* up
* fix
* up
* up
* up
* up
* up
* up
* handle modern types.
* up
* up
* fix ip adapter type checking.
* up
* up
* up
* up
* up
* up
* up
* revert docstring changes.
* keep deleted files deleted.
* keep deleted files deleted.
---------
Co-authored-by: Dhruv Nair <dhruv.nair@gmail.com>
* initial conversion script
* cosmos control net block
* CosmosAttention
* base model conversion
* wip
* pipeline updates
* convert controlnet
* pipeline: working without controls
* wip
* debugging
* Almost working
* temp
* control working
* cleanup + detail on neg_encoder_hidden_states
* convert edge
* pos emb for control latents
* convert all chkpts
* resolve TODOs
* remove prints
* Docs
* add siglip image reference encoder
* Add unit tests
* controlnet: add duplicate layers
* Additional tests
* skip less
* skip less
* remove image_ref
* minor
* docs
* remove skipped test in transfer
* Don't crash process
* formatting
* revert some changes
* remove skipped test
* make style
* Address comment + fix example
* CosmosAttnProcessor2_0 revert + CosmosAttnProcessor2_5 changes
* make style
* make fix-copies
