fix ckpt dir check (#320)

Co-authored-by: baojiangnan <baojiangnan@kuaishou.com>

Author: justadogistaken

scripts/train_eagle3.py

@@ -303,14 +303,15 @@ def build_draft_model(args: Namespace) -> Tuple[AutoDraftModelConfig, nn.Module]
 
     # Handle base ckpt, config file
     draft_model_last_checkpoint = None
-    if args.ckpt_dir is not None and os.path.isdir(args.ckpt_dir):
-        draft_model_config = os.path.join(args.ckpt_dir, "config.json")
-        draft_model_last_checkpoint = args.ckpt_dir
-        print_on_rank0(f"Finetuning from base model: {draft_model_last_checkpoint}")
-    else:
-        raise ValueError(
-            f"Provided base model dir {args.ckpt_dir} is not a valid directory."
-        )
+    if args.ckpt_dir is not None:
+        if os.path.isdir(args.ckpt_dir):
+            draft_model_config = os.path.join(args.ckpt_dir, "config.json")
+            draft_model_last_checkpoint = args.ckpt_dir
+            print_on_rank0(f"Finetuning from base model: {draft_model_last_checkpoint}")
+        else:
+            raise ValueError(
+                f"Provided base model dir {args.ckpt_dir} is not a valid directory."
+            )
 
     # detecting last ckpt for draft model
     if args.resume and os.path.isdir(args.output_dir):