add dummy imports

Makefile

@@ -74,8 +74,8 @@ fixup: modified_only_fixup extra_style_checks autogenerate_code repo-consistency
 # Make marked copies of snippets of codes conform to the original
 
 fix-copies:
-	python utils/check_table.py --fix_and_overwrite
 	python utils/check_dummies.py --fix_and_overwrite
+	python utils/check_table.py --fix_and_overwrite
 	python utils/check_copies.py --fix_and_overwrite
 
 # Run tests for the library

src/diffusers/__init__.py

@@ -3,18 +3,21 @@
 # module, but to preserve other warnings. So, don't check this module at all.
 from .utils import is_transformers_available
 
+
 __version__ = "0.0.4"
 
 from .modeling_utils import ModelMixin
 from .models.unet import UNetModel
-from .models.unet_grad_tts import UNetGradTTSModel
 from .models.unet_ldm import UNetLDMModel
 from .pipeline_utils import DiffusionPipeline
-from .pipelines import BDDM, DDIM, DDPM, GLIDE, PNDM, GradTTS, LatentDiffusion
+from .pipelines import BDDM, DDIM, DDPM, PNDM
 from .schedulers import DDIMScheduler, DDPMScheduler, GradTTSScheduler, PNDMScheduler, SchedulerMixin
 from .schedulers.classifier_free_guidance import ClassifierFreeGuidanceScheduler
 
+
 if is_transformers_available():
     from .models.unet_glide import GLIDESuperResUNetModel, GLIDETextToImageUNetModel, GLIDEUNetModel
+    from .models.unet_grad_tts import UNetGradTTSModel
+    from .pipelines import GLIDE, GradTTS, LatentDiffusion
 else:
     from .utils.dummy_transformers_objects import *

src/diffusers/pipelines/__init__.py

+from ..utils import is_transformers_available
 from .pipeline_bddm import BDDM
 from .pipeline_ddim import DDIM
 from .pipeline_ddpm import DDPM
-from .pipeline_grad_tts import GradTTS
-from .pipeline_glide import GLIDE
-from .pipeline_latent_diffusion import LatentDiffusion
 from .pipeline_pndm import PNDM
+
+
+if is_transformers_available():
+    from .pipeline_glide import GLIDE
+    from .pipeline_grad_tts import GradTTS
+    from .pipeline_latent_diffusion import LatentDiffusion

src/diffusers/pipelines/grad_tts_utils.py

@@ -6,11 +6,8 @@ from shutil import copyfile
 
 import torch
 
+from transformers import PreTrainedTokenizer
 
-try:
-    from transformers import PreTrainedTokenizer
-except:
-    print("transformers is not installed")
 
 try:
     from unidecode import unidecode

src/diffusers/pipelines/pipeline_glide.py

@@ -24,17 +24,11 @@ import torch.utils.checkpoint
 from torch import nn
 
 import tqdm
-
-
-try:
-    from transformers import CLIPConfig, CLIPModel, CLIPTextConfig, CLIPVisionConfig, GPT2Tokenizer
-    from transformers.activations import ACT2FN
-    from transformers.modeling_outputs import BaseModelOutput, BaseModelOutputWithPooling
-    from transformers.modeling_utils import PreTrainedModel
-    from transformers.utils import ModelOutput, add_start_docstrings_to_model_forward, replace_return_docstrings
-except:
-    print("Transformers is not installed")
-    pass
+from transformers import CLIPConfig, CLIPModel, CLIPTextConfig, CLIPVisionConfig, GPT2Tokenizer
+from transformers.activations import ACT2FN
+from transformers.modeling_outputs import BaseModelOutput, BaseModelOutputWithPooling
+from transformers.modeling_utils import PreTrainedModel
+from transformers.utils import ModelOutput, add_start_docstrings_to_model_forward, replace_return_docstrings
 
 from ..models import GLIDESuperResUNetModel, GLIDETextToImageUNetModel
 from ..pipeline_utils import DiffusionPipeline

src/diffusers/utils/__init__.py

@@ -11,11 +11,17 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from requests.exceptions import HTTPError
 import importlib
-import importlib_metadata
 import os
-from .logging import logger
+from collections import OrderedDict
+
+import importlib_metadata
+from requests.exceptions import HTTPError
+
+from .logging import get_logger
+
+
+logger = get_logger(__name__)
 
 
 hf_cache_home = os.path.expanduser(
@@ -56,3 +62,39 @@ class EntryNotFoundError(HTTPError):
 
 class RevisionNotFoundError(HTTPError):
     """Raised when trying to access a hf.co URL with a valid repository but an invalid revision."""
+
+
+TRANSFORMERS_IMPORT_ERROR = """
+{0} requires the transformers library but it was not found in your environment. You can install it with pip:
+`pip install accelerate`
+"""
+
+
+BACKENDS_MAPPING = OrderedDict(
+    [
+        ("transformers", (is_transformers_available, TRANSFORMERS_IMPORT_ERROR)),
+    ]
+)
+
+
+def requires_backends(obj, backends):
+    if not isinstance(backends, (list, tuple)):
+        backends = [backends]
+
+    name = obj.__name__ if hasattr(obj, "__name__") else obj.__class__.__name__
+    checks = (BACKENDS_MAPPING[backend] for backend in backends)
+    failed = [msg.format(name) for available, msg in checks if not available()]
+    if failed:
+        raise ImportError("".join(failed))
+
+
+class DummyObject(type):
+    """
+    Metaclass for the dummy objects. Any class inheriting from it will return the ImportError generated by
+    `requires_backend` each time a user tries to access any method of that class.
+    """
+
+    def __getattr__(cls, key):
+        if key.startswith("_"):
+            return super().__getattr__(cls, key)
+        requires_backends(cls, cls._backends)

src/diffusers/utils/dummy_transformers_objects.py

@@ -22,3 +22,27 @@ class GLIDEUNetModel(metaclass=DummyObject):
 
     def __init__(self, *args, **kwargs):
         requires_backends(self, ["transformers"])
+
+
+class UNetGradTTSModel(metaclass=DummyObject):
+    _backends = ["transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["transformers"])
+
+
+GLIDE = None
+
+
+class GradTTS(metaclass=DummyObject):
+    _backends = ["transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["transformers"])
+
+
+class LatentDiffusion(metaclass=DummyObject):
+    _backends = ["transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["transformers"])