Streaming generation is not working with automatic function calling

[lmsh7]

Environment details

• Programming language: Python
• OS: macOS
• Language runtime version: 3.12.7
• Package version: 0.4.0

Steps to reproduce

1. import os
   from google import genai
   from google.genai import types
   from google.genai.types import (
       GoogleSearch,
   )
   
   
   client = genai.Client(api_key=os.environ["GEMINI_API_KEY"])
   
   
   def search(query: str) -> str:
       return query
   
   
   # mytools = [{"google_search": GoogleSearch()}]
   mytools = [search]
   
   
   generation_config = types.GenerateContentConfig(
       temperature=1,
       top_p=0.95,
       top_k=40,
       max_output_tokens=8192,
       tools=mytools,
   )
   params = {
       "model": "gemini-2.0-flash-exp",
       "config": generation_config,
       "contents": "Search something about hongkong",
   }
   for chunk in client.models.generate_content_stream(**params):
       print(chunk.text)

2. Traceback (most recent call last):
     File "/Users/lmsh7/Code/project8/./bug_report.py", line 33, in <module>
       print(chunk.text)
             ^^^^^^^^^^
     File "/Users/lmsh7/Code/project8/.venv/lib/python3.12/site-packages/google/genai/types.py", line 2483, in text
       raise ValueError(
   ValueError: GenerateContentResponse.text only supports text parts, but got function_call partvideo_metadata=None thought=None code_execution_result=None executable_code=None file_data=None function_call=FunctionCall(id=None, args={'query': 'hongkong'}, name='search') function_response=None inline_data=None text=None

[Giom-V]

Hello @lmsh7, I think your issue is because you can't simply use chunk.text . You need to do something like:

if chuck.text  is not None:
  print(chunk.text)
elif chuck.function_call is not None:
  # do something, or maybe nothing.

[lmsh7]

Hello @lmsh7, I think your issue is because you can't simply use chunk.text . You need to do something like:

if chuck.text  is not None:
  print(chunk.text)
elif chuck.function_call is not None:
  # do something, or maybe nothing.

Could you provide a working example? When I attempt this...

Traceback (most recent call last):
  File "/Users/lmsh7/Code/project8/bug_report.py", line 33, in <module>
    if chunk.text is not None:
       ^^^^^^^^^^
  File "/Users/lmsh7/Code/project8/.venv/lib/python3.12/site-packages/google/genai/types.py", line 2483, in text
    raise ValueError(
ValueError: GenerateContentResponse.text only supports text parts, but got function_call partvideo_metadata=None thought=None code_execution_result=None executable_code=None file_data=None function_call=FunctionCall(id=None, args={'query': 'hongkong'}, name='search') function_response=None inline_data=None text=None

[Giom-V]

Try using chunk.candidates[0].content.parts[0] instead of chunk. That solves your error, but as far as I can see you still do not get the grounding data.

[lmsh7]

Try using chunk.candidates[0].content.parts[0] instead of chunk.

I tried this approach but the results were not what I expected:

# Using streaming approach
for chunk in client.models.generate_content_stream(**params):
    if chunk.candidates[0].content.parts[0] is not None:
        print(chunk.candidates[0].content.parts[0])

Output:

video_metadata=None thought=None code_execution_result=None executable_code=None file_data=None function_call=FunctionCall(id=None, args={'query': 'hongkong'}, name='search') function_response=None inline_data=None text=None
video_metadata=None thought=None code_execution_result=None executable_code=None file_data=None function_call=None function_response=None inline_data=None text=''

In comparison, when using the non-streaming approach:

# Using regular approach
response = client.models.generate_content(**params)
print(response.text)

Output:

I searched for "hongkong" and the API returned a result "hongkong". Is there anything else I can help you with?

[Giom-V]

You forgot the .text in your code.

Here's a more complete loop you can use:

for chunk in client.models.generate_content_stream(**params):
    for candidate in chunk.candidates:
      for part in candidate.content.parts:
        print(part.text)

[lmsh7]

You forgot the .text in your code.

Here's a more complete loop you can use:

for chunk in client.models.generate_content_stream(**params):
    for candidate in chunk.candidates:
      for part in candidate.content.parts:
        print(part.text)

Here is full code to reproduce, the result still None.

import os
from google import genai
from google.genai import types
from google.genai.types import (
    GoogleSearch,
)


client = genai.Client(api_key=os.environ["GEMINI_API_KEY"])


def search(query: str) -> str:
    return query


# mytools = [{"google_search": GoogleSearch()}]
mytools = [search]


generation_config = types.GenerateContentConfig(
    temperature=1,
    top_p=0.95,
    top_k=40,
    max_output_tokens=8192,
    tools=mytools,
)
params = {
    "model": "gemini-2.0-flash-exp",
    "config": generation_config,
    "contents": "Search something about hongkong",
}

# response = client.models.generate_content(**params)
# print(response.text)

for chunk in client.models.generate_content_stream(**params):
    for candidate in chunk.candidates:
        for part in candidate.content.parts:
            print(part.text)