fix: make sure that streaming works with function calls - (drop python3.8)

[anakin87]

Related Issues

Tests are failing: https://github.com/deepset-ai/haystack-core-integrations/actions/runs/11337043949
The conversion of function calls into dictionaries is not working properly.

Proposed Changes:

• Use the chunk dictionaries to access all required attributes (instead of Google Proto objects).
• Officially drop Python 3.8 in this package (google-generativeai never supported it)

How did you test it?

CI

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test:.

[Amnah199]

LG! Would you say we should also replace Proto objects approach for below non-stream responses to prevent any failures later?

haystack-core-integrations/integrations/google_ai/src/haystack_integrations/components/generators/google_ai/chat/gemini.py

Line 325 in a223e6f

elif part.function_call:

[anakin87]

LG! Would you say we should also replace Proto objects approach for below non-stream responses to prevent any failures later?

haystack-core-integrations/integrations/google_ai/src/haystack_integrations/components/generators/google_ai/chat/gemini.py

Line 325 in a223e6f

elif part.function_call:

Since this is working now and is covered by tests, I would leave it unchanged. But I leave the decision to you...

(Also, I envision a massive refactoring of this component, when we will add better support for tools.)

[Amnah199]

In that case, makes sense to refactor it once Tools are supported. Thanks for the fix.

[vblagoje]

@Amnah199 please review this one - I got stuck on other tasks