Merge remote-tracking branch 'origin/fix/pipeline-longtext-empty-response' into validation/test-build-with-fixes

# Conflicts:
#	tests/unit_tests/pipeline/test_longtext.py

src/langbot/pkg/pipeline/longtext/longtext.py

@@ -76,6 +76,10 @@ class LongTextProcessStage(stage.PipelineStage):
             self.ap.logger.debug('Long message processing strategy is not set, skip long message processing.')
             return entities.StageProcessResult(result_type=entities.ResultType.CONTINUE, new_query=query)
 
+        if not query.resp_message_chain:
+            self.ap.logger.debug('Response message chain is empty, skip long message processing.')
+            return entities.StageProcessResult(result_type=entities.ResultType.CONTINUE, new_query=query)
+
         # 检查是否包含非 Plain 组件
         contains_non_plain = False
 

tests/unit_tests/pipeline/test_longtext.py

@@ -166,6 +166,29 @@ class TestLongTextProcessStageProcess:
         assert isinstance(components[0], platform_message.Plain)
         assert components[0].text == 'short response'
 
+    @pytest.mark.asyncio
+    async def test_empty_response_message_chain_continues_without_processing(self):
+        """Empty response chains should be a no-op for long text processing."""
+        longtext = get_longtext_module()
+        entities = get_entities_module()
+
+        app = FakeApp()
+        stage = longtext.LongTextProcessStage(app)
+
+        pipeline_config = make_longtext_config(strategy='forward', threshold=1)
+
+        await stage.initialize(pipeline_config)
+
+        query = text_query("hello")
+        query.pipeline_config = pipeline_config
+        query.resp_message_chain = []
+
+        result = await stage.process(query, 'LongTextProcessStage')
+
+        assert result.result_type == entities.ResultType.CONTINUE
+        assert result.new_query is query
+        assert query.resp_message_chain == []
+
     @pytest.mark.asyncio
     async def test_non_plain_component_skips(self):
         """resp_message_chain with non-Plain components should skip processing."""