fix comments

src/promptflow/promptflow/_sdk/entities/_chat_group/_chat_group.py

@@ -119,6 +119,7 @@ def invoke(self):
         chat_round = 0
         chat_token = 0
         chat_start_time = time.time()
+        self._conversation_history = []
         while True:
             chat_round += 1
 
@@ -160,6 +161,8 @@ def _get_role_input_values(self, role: ChatRole) -> Dict[str, Any]:
             # initializing the chat role.
             if value == "${parent.conversation_history}":
                 value = self._conversation_history
+            elif isinstance(value, str) and value.startswith("${"):
+                raise ChatGroupError(f"Unresolved input value {value!r} for role {role.role!r}.")
             input_values[key] = value
         logger.debug(f"Input values for role {role.role!r}: {input_values!r}")
         return input_values

src/promptflow/promptflow/_sdk/entities/_chat_group/_chat_role.py

@@ -106,11 +106,11 @@ def _update_inputs_from_data_and_inputs(self, data: Dict, inputs: Dict):
                 if value.startswith(data_prefix):
                     stripped_value = value.replace(data_prefix, "").replace("}", "")
                     data_name, col_name = stripped_value.split(".")
-                    if data_name in data:
+                    if data_name in data and col_name in data[data_name]:
                         current_input["value"] = data[data_name][col_name]
                 elif value.startswith(inputs_prefix):
                     input_name = value.replace(inputs_prefix, "").replace("}", "")
-                    if input_name in inputs:
+                    if input_name in inputs and input_name in inputs:
                         current_input["value"] = inputs[input_name]
 
     def invoke(self, *args, **kwargs):