fix(infer): raise the intended ValueError when tool_choice names an unknown tool

swift/infer_engine/protocol.py

@@ -247,7 +247,7 @@ def __post_init__(self):
                 self.tools = None
             elif isinstance(self.tool_choice, dict):
                 name = self.tool_choice['function']['name']
-                tool = next(tool for tool in self.tools if tool['function']['name'] == name)
+                tool = next((tool for tool in self.tools if tool['function']['name'] == name), None)
                 if tool is None:
                     raise ValueError(f"Tool choice '{name}' not found in tools.")
                 self.tools = [tool]

tests/general/test_protocol_tool_choice.py

@@ -0,0 +1,43 @@
+import unittest
+
+from swift.infer_engine.protocol import ChatCompletionRequest
+
+
+def _request(tool_choice):
+    tools = [
+        {
+            'type': 'function',
+            'function': {
+                'name': 'get_weather'
+            }
+        },
+        {
+            'type': 'function',
+            'function': {
+                'name': 'get_time'
+            }
+        },
+    ]
+    return ChatCompletionRequest(
+        model='test', messages=[{
+            'role': 'user',
+            'content': 'hi'
+        }], tools=tools, tool_choice=tool_choice)
+
+
+class TestChatCompletionRequestToolChoice(unittest.TestCase):
+
+    def test_selected_tool_keeps_only_that_tool(self):
+        request = _request({'type': 'function', 'function': {'name': 'get_time'}})
+        self.assertEqual([tool['function']['name'] for tool in request.tools], ['get_time'])
+
+    def test_unknown_tool_raises_value_error(self):
+        with self.assertRaisesRegex(ValueError, "Tool choice 'no_such_tool' not found in tools."):
+            _request({'type': 'function', 'function': {'name': 'no_such_tool'}})
+
+    def test_string_tool_choice_keeps_every_tool(self):
+        self.assertEqual(len(_request('auto').tools), 2)
+
+
+if __name__ == '__main__':
+    unittest.main()