Raise FutureWarning for trainer moved to experimental

trl/trainer/cpo_trainer.py

@@ -28,6 +28,8 @@ def __init__(self, *args, **kwargs):
         warnings.warn(
             "The `CPOTrainer` is now located in `trl.experimental`. Please update your imports to "
             "`from trl.experimental.cpo import CPOTrainer`. The current import path will be removed and no longer "
-            "supported in TRL 0.29. For more information, see https://github.com/huggingface/trl/issues/4223."
+            "supported in TRL 0.29. For more information, see https://github.com/huggingface/trl/issues/4223.",
+            FutureWarning,
+            stacklevel=2,
         )
         super().__init__(*args, **kwargs)

trl/trainer/kto_trainer.py

@@ -366,6 +366,7 @@ def __init__(
                 "it and want it to remain, please share your comments here: "
                 "https://github.com/huggingface/trl/issues/4223. Silence this warning by setting environment variable "
                 "TRL_EXPERIMENTAL_SILENCE=1.",
+                FutureWarning,
                 stacklevel=2,
             )
         if type(args) is TrainingArguments:

trl/trainer/rloo_trainer.py

@@ -248,6 +248,7 @@ def __init__(
                 "it and want it to remain, please share your comments here: "
                 "https://github.com/huggingface/trl/issues/4223. Silence this warning by setting environment variable "
                 "TRL_EXPERIMENTAL_SILENCE=1.",
+                FutureWarning,
                 stacklevel=2,
             )