[Bugfix][Frontend] Reject LoRA adapters named after a served model

tests/entrypoints/serve/lora/test_serving_models.py

@@ -99,6 +99,22 @@ async def test_load_lora_adapter_duplicate():
     assert len(serving_models.lora_requests) == 1
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize("load_inplace", [False, True])
+async def test_load_lora_adapter_base_model_name(load_inplace: bool):
+    """A LoRA named after a served model would shadow it for all requests."""
+    serving_models = await _async_serving_models_init()
+    request = LoadLoRAAdapterRequest(
+        lora_name=MODEL_NAME, lora_path="/path/to/adapter", load_inplace=load_inplace
+    )
+    response = await serving_models.load_lora_adapter(request)
+    assert isinstance(response, ErrorResponse)
+    assert response.error.type == "InvalidUserInput"
+    assert response.error.code == HTTPStatus.BAD_REQUEST
+    assert len(serving_models.lora_requests) == 0
+    serving_models.engine_client.add_lora.assert_not_called()
+
+
 @pytest.mark.asyncio
 async def test_unload_lora_adapter_success():
     serving_models = await _async_serving_models_init()

vllm/entrypoints/openai/models/serving.py

@@ -245,6 +245,14 @@ async def _check_load_lora_adapter_request(
                 status_code=HTTPStatus.BAD_REQUEST,
             )
 
+        if self.is_base_model(request.lora_name):
+            return create_error_response(
+                message=f"The lora adapter '{request.lora_name}' conflicts with a "
+                "served base model.",
+                err_type="InvalidUserInput",
+                status_code=HTTPStatus.BAD_REQUEST,
+            )
+
         # If not loading inplace
         # Check if the lora adapter with the given name already exists
         if not request.load_inplace and request.lora_name in self.lora_requests: