Research role fails if some of Serpapi searches return no results

[igor-pechersky]

Bug description
Research role fails if some of Serpapi searches return no results

Reproduction
Configuration

llm:
  api_type: "openai"  
  model: "gpt-4o"  
  base_url: "https://api.openai.com/v1"  # or forward url / other llm url
  api_key: "sk-XXX"

search:
  api_type: 'serpapi' 
  api_key: 'XXX'
  params:
    tbs: qdr:y #last year
    gl: us
    hl: en

Command line

python3 -m metagpt.roles.researcher 'Coulianu Tozgrec'
----
python3 -m metagpt.roles.researcher 'Compare LLM Agent Frameworks, such as AutoGen, MetaGPT, Lyzr, GPTSwarm, Langroid, and crewAI'

Bug solved method
PR 1357

Environment information

• LLM type and model name: gpt-4o
• System version: Linux codespaces-27135d 6.5.0-1021-azure
• Python version: Python 3.9.17
• MetaGPT version or branch: main, after 38cea1d

Screenshots or logs

Traceback (most recent call last):
  File "/workspaces/MetaGPT/metagpt/utils/common.py", line 640, in wrapper
    return await func(self, *args, **kwargs)
  File "/workspaces/MetaGPT/metagpt/roles/role.py", line 550, in run
    rsp = await self.react()
  File "/workspaces/MetaGPT/metagpt/roles/researcher.py", line 96, in react
    msg = await super().react()
  File "/workspaces/MetaGPT/metagpt/roles/role.py", line 519, in react
    rsp = await self._react()
  File "/workspaces/MetaGPT/metagpt/roles/role.py", line 474, in _react
    rsp = await self._act()
  File "/workspaces/MetaGPT/metagpt/roles/researcher.py", line 63, in _act
    summaries = await asyncio.gather(*todos)
  File "/workspaces/MetaGPT/metagpt/roles/researcher.py", line 61, in <genexpr>
    todos = (todo.run(*url, query=query, system_text=research_system_text) for (query, url) in links.items())
TypeError: run() missing 1 required positional argument: 'url'

Traceback (most recent call last):
  File "/usr/local/lib/python3.9/runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/local/lib/python3.9/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/workspaces/MetaGPT/metagpt/roles/researcher.py", line 117, in <module>
    fire.Fire(main)
  File "/usr/local/lib/python3.9/site-packages/fire/core.py", line 141, in Fire
    component_trace = _Fire(component, args, parsed_flag_args, context, name)
  File "/usr/local/lib/python3.9/site-packages/fire/core.py", line 466, in _Fire
    component, remaining_args = _CallAndUpdateTrace(
  File "/usr/local/lib/python3.9/site-packages/fire/core.py", line 679, in _CallAndUpdateTrace
    component = loop.run_until_complete(fn(*varargs, **kwargs))
  File "/usr/local/lib/python3.9/asyncio/base_events.py", line 647, in run_until_complete
    return future.result()
  File "/workspaces/MetaGPT/metagpt/roles/researcher.py", line 115, in main
    await role.run(topic)
  File "/workspaces/MetaGPT/metagpt/utils/common.py", line 662, in wrapper
    raise Exception(format_trackback_info(limit=None))
Exception: Traceback (most recent call last):
  File "/workspaces/MetaGPT/metagpt/utils/common.py", line 640, in wrapper
    return await func(self, *args, **kwargs)
  File "/workspaces/MetaGPT/metagpt/roles/role.py", line 550, in run
    rsp = await self.react()
  File "/workspaces/MetaGPT/metagpt/roles/researcher.py", line 96, in react
    msg = await super().react()
  File "/workspaces/MetaGPT/metagpt/roles/role.py", line 519, in react
    rsp = await self._react()
  File "/workspaces/MetaGPT/metagpt/roles/role.py", line 474, in _react
    rsp = await self._act()
  File "/workspaces/MetaGPT/metagpt/roles/researcher.py", line 55, in _act
    links = await todo.run(topic, 8, 8)
  File "/workspaces/MetaGPT/metagpt/actions/research.py", line 120, in run
    results = await asyncio.gather(*(self.search_engine.run(i, as_string=False) for i in keywords))
  File "/workspaces/MetaGPT/metagpt/tools/search_engine.py", line 164, in run
    raise e
  File "/workspaces/MetaGPT/metagpt/tools/search_engine.py", line 159, in run
    return await self.run_func(query, max_results=max_results, as_string=as_string)
  File "/workspaces/MetaGPT/metagpt/tools/search_engine_serpapi.py", line 47, in run
    return self._process_response(result, as_string=as_string)
  File "/workspaces/MetaGPT/metagpt/tools/search_engine_serpapi.py", line 90, in _process_response
    raise ValueError(f"Got error from SerpAPI: {res['error']}")
ValueError: Got error from SerpAPI: Google hasn't returned any results for this query.

[shenchucheng]

Thank you for your PR #1357 to fix this issue. Now that it has been merged, we will be closing this issue.