Lazy Import for Diffusers (#4829)

* initial commit

* move modules to import struct

* add dummy objects and _LazyModule

* add lazy import to schedulers

* clean up unused imports

* lazy import on models module

* lazy import for schedulers module

* add lazy import to pipelines module

* lazy import altdiffusion

* lazy import audio diffusion

* lazy import audioldm

* lazy import consistency model

* lazy import controlnet

* lazy import dance diffusion ddim ddpm

* lazy import deepfloyd

* lazy import kandinksy

* lazy imports

* lazy import semantic diffusion

* lazy imports

* lazy import stable diffusion

* move sd output to its own module

* clean up

* lazy import t2iadapter

* lazy import unclip

* lazy import versatile and vq diffsuion

* lazy import vq diffusion

* helper to fetch objects from modules

* lazy import sdxl

* lazy import txt2vid

* lazy import stochastic karras

* fix model imports

* fix bug

* lazy import

* clean up

* clean up

* fixes for tests

* fixes for tests

* clean up

* remove import of torch_utils from utils module

* clean up

* clean up

* fix mistake import statement

* dedicated modules for exporting and loading

* remove testing utils from utils module

* fixes from  merge conflicts

* Update src/diffusers/pipelines/kandinsky2_2/__init__.py

* fix docs

* fix alt diffusion copied from

* fix check dummies

* fix more docs

* remove accelerate import from utils module

* add type checking

* make style

* fix check dummies

* remove torch import from xformers check

* clean up error message

* fixes after upstream merges

* dummy objects fix

* fix tests

* remove unused module import

---------
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>

tests/schedulers/test_scheduler_dpm_sde.py

 import torch
 
 from diffusers import DPMSolverSDEScheduler
-from diffusers.utils import torch_device
-from diffusers.utils.testing_utils import require_torchsde
+from diffusers.utils.testing_utils import require_torchsde, torch_device
 
 from .test_schedulers import SchedulerCommonTest
 

tests/schedulers/test_scheduler_euler.py

 import torch
 
 from diffusers import EulerDiscreteScheduler
-from diffusers.utils import torch_device
+from diffusers.utils.testing_utils import torch_device
 
 from .test_schedulers import SchedulerCommonTest
 

tests/schedulers/test_scheduler_euler_ancestral.py

 import torch
 
 from diffusers import EulerAncestralDiscreteScheduler
-from diffusers.utils import torch_device
+from diffusers.utils.testing_utils import torch_device
 
 from .test_schedulers import SchedulerCommonTest
 

tests/schedulers/test_scheduler_heun.py

 import torch
 
 from diffusers import HeunDiscreteScheduler
-from diffusers.utils import torch_device
+from diffusers.utils.testing_utils import torch_device
 
 from .test_schedulers import SchedulerCommonTest
 

tests/schedulers/test_scheduler_kdpm2_ancestral.py

 import torch
 
 from diffusers import KDPM2AncestralDiscreteScheduler
-from diffusers.utils import torch_device
+from diffusers.utils.testing_utils import torch_device
 
 from .test_schedulers import SchedulerCommonTest
 

tests/schedulers/test_scheduler_kdpm2_discrete.py

 import torch
 
 from diffusers import KDPM2DiscreteScheduler
-from diffusers.utils import torch_device
+from diffusers.utils.testing_utils import torch_device
 
 from .test_schedulers import SchedulerCommonTest
 

tests/schedulers/test_scheduler_lms.py

 import torch
 
 from diffusers import LMSDiscreteScheduler
-from diffusers.utils import torch_device
+from diffusers.utils.testing_utils import torch_device
 
 from .test_schedulers import SchedulerCommonTest
 

tests/schedulers/test_schedulers.py

@@ -40,8 +40,7 @@ from diffusers import (
 )
 from diffusers.configuration_utils import ConfigMixin, register_to_config
 from diffusers.schedulers.scheduling_utils import SchedulerMixin
-from diffusers.utils import torch_device
-from diffusers.utils.testing_utils import CaptureLogger
+from diffusers.utils.testing_utils import CaptureLogger, torch_device
 
 from ..others.test_utils import TOKEN, USER, is_staging_test
 

utils/check_copies.py

@@ -15,7 +15,6 @@
 
 import argparse
 import glob
-import importlib.util
 import os
 import re
 
@@ -29,15 +28,6 @@ DIFFUSERS_PATH = "src/diffusers"
 REPO_PATH = "."
 
 
-# This is to make sure the diffusers module imported is the one in the repo.
-spec = importlib.util.spec_from_file_location(
-    "diffusers",
-    os.path.join(DIFFUSERS_PATH, "__init__.py"),
-    submodule_search_locations=[DIFFUSERS_PATH],
-)
-diffusers_module = spec.loader.load_module()
-
-
 def _should_continue(line, indent):
     return line.startswith(indent) or len(line) <= 1 or re.search(r"^\s*\)(\s*->.*:|:)\s*$", line) is not None
 

utils/check_dummies.py

@@ -71,24 +71,27 @@ def read_init():
 
     # Get to the point we do the actual imports for type checking
     line_index = 0
+    while not lines[line_index].startswith("if TYPE_CHECKING"):
+        line_index += 1
+
     backend_specific_objects = {}
     # Go through the end of the file
     while line_index < len(lines):
         # If the line contains is_backend_available, we grab all objects associated with the `else` block
         backend = find_backend(lines[line_index])
         if backend is not None:
-            while not lines[line_index].startswith("else:"):
+            while not lines[line_index].startswith("    else:"):
                 line_index += 1
             line_index += 1
             objects = []
             # Until we unindent, add backend objects to the list
-            while line_index < len(lines) and len(lines[line_index]) > 1:
+            while len(lines[line_index]) <= 1 or lines[line_index].startswith(" " * 8):
                 line = lines[line_index]
                 single_line_import_search = _re_single_line_import.search(line)
                 if single_line_import_search is not None:
                     objects.extend(single_line_import_search.groups()[0].split(", "))
-                elif line.startswith(" " * 8):
-                    objects.append(line[8:-2])
+                elif line.startswith(" " * 12):
+                    objects.append(line[12:-2])
                 line_index += 1
 
             if len(objects) > 0: