Use _import_structure for lazy loading

src/diffusers/pipelines/photon/__init__.py

@@ -1,16 +1,65 @@
 from typing import TYPE_CHECKING
 
-from .pipeline_output import PhotonPipelineOutput
-from .pipeline_photon import PhotonPipeline
+from ...utils import (
+    DIFFUSERS_SLOW_IMPORT,
+    OptionalDependencyNotAvailable,
+    _LazyModule,
+    get_objects_from_module,
+    is_torch_available,
+    is_transformers_available,
+)
 
 
-__all__ = ["PhotonPipeline", "PhotonPipelineOutput"]
+_dummy_objects = {}
+_additional_imports = {}
+_import_structure = {"pipeline_output": ["PhotonPipelineOutput"]}
 
-# Make T5GemmaEncoder importable from this module for pipeline loading
-if TYPE_CHECKING:
-    from transformers.models.t5gemma.modeling_t5gemma import T5GemmaEncoder
+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:
-    try:
+    _import_structure["pipeline_photon"] = ["PhotonPipeline"]
+
+# Import T5GemmaEncoder for pipeline loading compatibility
+try:
+    if is_transformers_available():
         from transformers.models.t5gemma.modeling_t5gemma import T5GemmaEncoder
+
+        _additional_imports["T5GemmaEncoder"] = T5GemmaEncoder
+except ImportError:
+    pass
+
+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 .pipeline_output import PhotonPipelineOutput
+        from .pipeline_photon import PhotonPipeline
+
+    try:
+        if is_transformers_available():
+            from transformers.models.t5gemma.modeling_t5gemma import T5GemmaEncoder
     except ImportError:
         pass
+
+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)
+    for name, value in _additional_imports.items():
+        setattr(sys.modules[__name__], name, value)