add warning messages.

Author: sayakpaul

src/diffusers/pipelines/pipeline_flax_utils.py

@@ -312,6 +312,11 @@ def from_pretrained(cls, pretrained_model_name_or_path: Optional[Union[str, os.P
         >>> dpm_params["scheduler"] = dpmpp_state
         ```
         """
+        logger.warning(
+            "Flax classes are deprecated and will be removed in Diffusers v1. We "
+            "recommend migrating to PyTorch classes or pinning your version of Diffusers."
+        )
+
         cache_dir = kwargs.pop("cache_dir", None)
         proxies = kwargs.pop("proxies", None)
         local_files_only = kwargs.pop("local_files_only", False)

src/diffusers/schedulers/scheduling_utils_flax.py

@@ -22,9 +22,11 @@
 import jax.numpy as jnp
 from huggingface_hub.utils import validate_hf_hub_args
 
-from ..utils import BaseOutput, PushToHubMixin
+from ..utils import BaseOutput, PushToHubMixin, logging
 
 
+logger = logging.get_logger(__name__)
+
 SCHEDULER_CONFIG_NAME = "scheduler_config.json"
 
 
@@ -133,6 +135,10 @@ def from_pretrained(
         </Tip>
 
         """
+        logger.warning(
+            "Flax classes are deprecated and will be removed in Diffusers v1. We "
+            "recommend migrating to PyTorch classes or pinning your version of Diffusers."
+        )
         config, kwargs = cls.load_config(
             pretrained_model_name_or_path=pretrained_model_name_or_path,
             subfolder=subfolder,