[P0] Fixing trainer saving due to FSDP integration

Author: frankaging

pyreft/reft_trainer.py

@@ -66,13 +66,33 @@ def make_dataloader(
 
 class ReftTrainer(Trainer):
     def save_model(self, output_dir, _internal_call=False):
-        if dist.get_rank() == 0:
-            if not os.path.exists(output_dir):
-                os.makedirs(output_dir)
-            self.model.save_intervention(
-                save_directory=f"{output_dir}/intervenable_model", 
-                include_model=True
-            )
+        # Handle CPU training and non-distributed cases
+        try:
+            is_main_process = not dist.is_initialized() or dist.get_rank() == 0
+        except (RuntimeError, AttributeError) as e:  # Catches case when torch.distributed is not available or other dist errors
+            logger.error(f"Error checking distributed training status: {str(e)}")
+            is_main_process = True
+        
+        if is_main_process:
+            target_dir = f"{output_dir}/intervenable_model"
+            # Log warning if target directory exists and has content
+            if os.path.exists(target_dir) and os.listdir(target_dir):
+                logger.warning(
+                    f"Directory {target_dir} already exists and contains files. "
+                    "Skipping save to prevent overwriting existing model."
+                )
+                return
+                
+            try:
+                if not os.path.exists(output_dir):
+                    os.makedirs(output_dir)
+                self.model.save_intervention(
+                    save_directory=target_dir, 
+                    include_model=True
+                )
+            except Exception as e:
+                logger.error(f"Error saving model to {target_dir}: {str(e)}")
+                raise  # Re-raise the exception after logging
 
     def _load_best_model(self):
         logger.warning(f"Loading best model from {self.state.best_model_checkpoint} (score: {self.state.best_metric}).")