Re-enable send button and remove placeholder on stop (#6033)

panel/chat/feed.py

@@ -211,6 +211,9 @@ class ChatFeed(ListPanel):
     _callback_state = param.ObjectSelector(objects=list(CallbackState), doc="""
         The current state of the callback.""")
 
+    _was_disabled = param.Boolean(default=False, doc="""
+        The previous disabled state of the feed.""")
+
     _stylesheets: ClassVar[List[str]] = [f"{CDN_DIST}css/chat_feed.css"]
 
     def __init__(self, *objects, **params):
@@ -441,7 +444,7 @@ async def _prepare_response(self, _) -> None:
         if self.callback is None:
             return
 
-        disabled = self.disabled
+        self._was_disabled = self.disabled
         try:
             with param.parameterized.batch_call_watchers(self):
                 self.disabled = True
@@ -485,8 +488,8 @@ async def _prepare_response(self, _) -> None:
         finally:
             with param.parameterized.batch_call_watchers(self):
                 self._replace_placeholder(None)
-                self.disabled = disabled
                 self._callback_state = CallbackState.IDLE
+                self.disabled = self._was_disabled
 
     # Public API
 
@@ -607,15 +610,20 @@ def stop(self) -> bool:
         Whether the task was successfully stopped or done.
         """
         if self._callback_future is None:
-            return False
+            cancelled = False
         elif self._callback_state == CallbackState.GENERATING:
             # cannot cancel generator directly as it's already "finished"
             # by the time cancel is called; instead, set the state to STOPPING
             # and let upsert_message raise StopCallback
             self._callback_state = CallbackState.STOPPING
-            return True
+            cancelled = True
         else:
-            return self._callback_future.cancel()
+            cancelled = self._callback_future.cancel()
+
+        if cancelled:
+            self.disabled = self._was_disabled
+            self._replace_placeholder(None)
+        return cancelled
 
     def undo(self, count: int = 1) -> List[Any]:
         """

panel/tests/chat/test_interface.py

@@ -6,6 +6,7 @@
 from panel.chat.interface import ChatInterface
 from panel.layout import Row, Tabs
 from panel.pane import Image
+from panel.tests.util import wait_until
 from panel.widgets.button import Button
 from panel.widgets.input import FileInput, TextAreaInput, TextInput
 
@@ -92,6 +93,7 @@ async def callback(msg, user, instance):
             assert send_button.name == "Send"
             assert stop_button.name == "Stop"
             assert send_button.visible
+            assert not send_button.disabled
             assert not stop_button.visible
             yield "B"  # should not stream this
 
@@ -103,6 +105,7 @@ async def callback(msg, user, instance):
         assert send_button.name == "Send"
         assert stop_button.name == "Stop"
         assert send_button.visible
+        assert not send_button.disabled
         assert not stop_button.visible
 
     def test_show_stop_for_async(self, chat_interface: ChatInterface):
@@ -116,6 +119,8 @@ async def callback(msg, user, instance):
 
         chat_interface.callback = callback
         chat_interface.send("Message", respond=True)
+        send_button = chat_interface._input_layout[1]
+        assert not send_button.disabled
 
     def test_show_stop_for_sync(self, chat_interface: ChatInterface):
         def callback(msg, user, instance):
@@ -128,6 +133,30 @@ def callback(msg, user, instance):
 
         chat_interface.callback = callback
         chat_interface.send("Message", respond=True)
+        send_button = chat_interface._input_layout[1]
+        assert not send_button.disabled
+
+    def test_click_stop(self, chat_interface: ChatInterface):
+        async def callback(msg, user, instance):
+            send_button = instance._input_layout[1]
+            stop_button = instance._input_layout[2]
+            assert send_button.name == "Send"
+            assert stop_button.name == "Stop"
+            assert not send_button.visible
+            assert stop_button.visible
+            wait_until(lambda: len(instance.objects) == 2)
+            assert instance._placeholder in instance.objects
+            instance._click_stop(None)
+            assert send_button.visible
+            assert not send_button.disabled
+            assert not stop_button.visible
+            assert instance._placeholder not in instance.objects
+
+        chat_interface.callback = callback
+        chat_interface.placeholder_threshold = 0.001
+        chat_interface.send("Message", respond=True)
+        send_button = chat_interface._input_layout[1]
+        assert not send_button.disabled
 
     @pytest.mark.parametrize("widget", [TextInput(), TextAreaInput()])
     def test_auto_send_types(self, chat_interface: ChatInterface, widget):