[ray] Fix `datasets_modules` ImportError with Ray Tune (#12749)

* Fix dynamic_modules ImportError with Ray Tune

* Nit

src/transformers/integrations.py

@@ -14,12 +14,15 @@
 """
 Integrations with other Python libraries.
 """
+import functools
 import importlib.util
 import numbers
 import os
+import sys
 import tempfile
 from pathlib import Path
 
+from .file_utils import is_datasets_available
 from .utils import logging
 
 
@@ -246,8 +249,34 @@ def run_hp_search_ray(trainer, n_trials: int, direction: str, **kwargs) -> BestR
                 "Trainer `args`.".format(cls=type(kwargs["scheduler"]).__name__)
             )
 
+    trainable = ray.tune.with_parameters(_objective, local_trainer=trainer)
+
+    @functools.wraps(trainable)
+    def dynamic_modules_import_trainable(*args, **kwargs):
+        """
+        Wrapper around ``tune.with_parameters`` to ensure datasets_modules are loaded on each Actor.
+
+        Without this, an ImportError will be thrown. See https://github.com/huggingface/transformers/issues/11565.
+
+        Assumes that ``_objective``, defined above, is a function.
+        """
+        if is_datasets_available():
+            import datasets.load
+
+            dynamic_modules_path = os.path.join(datasets.load.init_dynamic_modules(), "__init__.py")
+            # load dynamic_modules from path
+            spec = importlib.util.spec_from_file_location("datasets_modules", dynamic_modules_path)
+            datasets_modules = importlib.util.module_from_spec(spec)
+            sys.modules[spec.name] = datasets_modules
+            spec.loader.exec_module(datasets_modules)
+        return trainable(*args, **kwargs)
+
+    # special attr set by tune.with_parameters
+    if hasattr(trainable, "__mixins__"):
+        dynamic_modules_import_trainable.__mixins__ = trainable.__mixins__
+
     analysis = ray.tune.run(
-        ray.tune.with_parameters(_objective, local_trainer=trainer),
+        dynamic_modules_import_trainable,
         config=trainer.hp_space(None),
         num_samples=n_trials,
         **kwargs,