fix #3317

Former-commit-id: 7dce1763be4374cf616d96db95ae964ff510a9d6

src/llmtuner/webui/chatter.py

@@ -2,12 +2,10 @@ import json
 import os
 from typing import TYPE_CHECKING, Any, Dict, Generator, List, Optional, Sequence, Tuple
 
-import gradio as gr
-from gradio.components import Component  # cannot use TYPE_CHECKING here
-
 from ..chat import ChatModel
 from ..data import Role
 from ..extras.misc import torch_gc
+from ..extras.packages import is_gradio_available
 from .common import get_save_dir
 from .locales import ALERTS
 
@@ -17,6 +15,11 @@ if TYPE_CHECKING:
     from .manager import Manager
 
 
+if is_gradio_available():
+    import gradio as gr
+    from gradio.components import Component  # cannot use TYPE_CHECKING here
+
+
 class WebChatModel(ChatModel):
     def __init__(self, manager: "Manager", demo_mode: bool = False, lazy_init: bool = True) -> None:
         self.manager = manager