feat: Add Modular Pipeline for Stable Diffusion 3 (SD3)

src/diffusers/__init__.py

@@ -463,6 +463,8 @@
             "QwenImageLayeredAutoBlocks",
             "QwenImageLayeredModularPipeline",
             "QwenImageModularPipeline",
+            "StableDiffusion3AutoBlocks",
+            "StableDiffusion3ModularPipeline",
             "StableDiffusionXLAutoBlocks",
             "StableDiffusionXLModularPipeline",
             "Wan22Blocks",
@@ -1242,6 +1244,8 @@
             QwenImageLayeredAutoBlocks,
             QwenImageLayeredModularPipeline,
             QwenImageModularPipeline,
+            StableDiffusion3AutoBlocks,
+            StableDiffusion3ModularPipeline,
             StableDiffusionXLAutoBlocks,
             StableDiffusionXLModularPipeline,
             Wan22Blocks,

src/diffusers/modular_pipelines/__init__.py

@@ -46,6 +46,7 @@
         "InsertableDict",
     ]
     _import_structure["stable_diffusion_xl"] = ["StableDiffusionXLAutoBlocks", "StableDiffusionXLModularPipeline"]
+    _import_structure["stable_diffusion_3"] = ["StableDiffusion3AutoBlocks", "StableDiffusion3ModularPipeline"]
     _import_structure["wan"] = [
         "WanBlocks",
         "Wan22Blocks",
@@ -140,6 +141,7 @@
             QwenImageLayeredModularPipeline,
             QwenImageModularPipeline,
         )
+        from .stable_diffusion_3 import StableDiffusion3AutoBlocks, StableDiffusion3ModularPipeline
         from .stable_diffusion_xl import StableDiffusionXLAutoBlocks, StableDiffusionXLModularPipeline
         from .wan import (
             Wan22Blocks,

src/diffusers/modular_pipelines/modular_pipeline.py

@@ -119,6 +119,7 @@ def _helios_pyramid_map_fn(config_dict=None):
 MODULAR_PIPELINE_MAPPING = OrderedDict(
     [
         ("stable-diffusion-xl", _create_default_map_fn("StableDiffusionXLModularPipeline")),
+        ("stable-diffusion-3", _create_default_map_fn("StableDiffusion3ModularPipeline")),
         ("wan", _wan_map_fn),
         ("wan-i2v", _wan_i2v_map_fn),
         ("flux", _create_default_map_fn("FluxModularPipeline")),

src/diffusers/modular_pipelines/stable_diffusion_3/__init__.py

@@ -0,0 +1,48 @@
+from typing import TYPE_CHECKING
+
+from ...utils import (
+    DIFFUSERS_SLOW_IMPORT,
+    OptionalDependencyNotAvailable,
+    _LazyModule,
+    get_objects_from_module,
+    is_torch_available,
+    is_transformers_available,
+)
+
+_dummy_objects = {}
+_import_structure = {}
+
+try:
+    if not (is_transformers_available() and is_torch_available()):
+        raise OptionalDependencyNotAvailable()
+except OptionalDependencyNotAvailable:
+    from ...utils import dummy_torch_and_transformers_objects  # noqa F403
+
+    _dummy_objects.update(get_objects_from_module(dummy_torch_and_transformers_objects))
+else:
+    _import_structure["modular_blocks_stable_diffusion_3"] = [
+        "StableDiffusion3AutoBlocks"
+    ]
+    _import_structure["modular_pipeline"] = ["StableDiffusion3ModularPipeline"]
+
+if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
+    try:
+        if not (is_transformers_available() and is_torch_available()):
+            raise OptionalDependencyNotAvailable()
+    except OptionalDependencyNotAvailable:
+        from ...utils.dummy_torch_and_transformers_objects import *  # noqa F403
+    else:
+        from .modular_blocks_stable_diffusion_3 import StableDiffusion3AutoBlocks
+        from .modular_pipeline import StableDiffusion3ModularPipeline
+else:
+    import sys
+
+    sys.modules[__name__] = _LazyModule(
+        __name__,
+        globals()["__file__"],
+        _import_structure,
+        module_spec=__spec__,
+    )
+
+    for name, value in _dummy_objects.items():
+        setattr(sys.modules[__name__], name, value)