fix: use functools.wraps in activity_tool to preserve __annotations__ and __module__

[brucearctor]

Summary

Replace manual metadata copying in activity_tool() with @functools.wraps(activity_def) to fix missing __annotations__ and __module__ on the wrapper function.

Problem

The activity_tool() wrapper copies __name__, __doc__, and __signature__ but misses __annotations__ and __module__. ADK's build_function_declaration() → _handle_params_as_deferred_annotations() reads the wrapper's __annotations__ to resolve parameter types, but finds {'args': Any, 'kw': Any} instead of the original function's typed parameters, causing a KeyError.

Fix

+import functools

 def activity_tool(activity_def, **kwargs):
+    @functools.wraps(activity_def)
     async def wrapper(*args, **kw):
         ...

-    wrapper.__name__ = activity_def.__name__
-    wrapper.__doc__ = activity_def.__doc__
-    setattr(wrapper, "__signature__", inspect.signature(activity_def))
+    wrapper.__signature__ = inspect.signature(activity_def)
     return wrapper

functools.wraps copies __name__, __qualname__, __module__, __annotations__, __doc__, __dict__, and sets __wrapped__. The explicit __signature__ override remains because the wrapper uses *args/**kw.

Testing

Verified locally: wrapping a typed activity with activity_tool() and using it as a LlmAgent tool now produces correct function declarations without KeyError.

Fixes #1635

[brianstrauch]

Thanks for the PR, happy to merge it in! Can you fix the lint and add a test?

[brucearctor]

Thanks for the PR, happy to merge it in! Can you fix the lint and add a test?

On it.

ALso -- it'd be great if we can get some sort of default linter in some sort of precommit hook [ i tend to like lefthook ] at least to be able to easily opt into. Otherwise, I imagine this will continue to happen [ I forget things, but not if the machines make sure I do ].

I tend to make those things rather automatic for people. But, at least if there is an easy and persistent opt-in/enablement, that'd also be sufficient.

[brucearctor]

Thanks @brianstrauch! Done — force-pushed with both fixes:

1. Lint: Fixed pyright error on wrapper.__signature__ — switched back to setattr() (matching the original pattern) since pyright cant resolve attributes on functools.wraps return types.

2. Test: Added test_activity_tool_preserves_metadata that verifies all the critical metadata attributes:

   • __name__, __doc__ (previously covered by manual copy)
   • __annotations__ (was missing — the bug)
   • __module__ (was missing — the bug)
   • __signature__ (parameters, types, defaults)

[brianstrauch]

Looks like changes to temporalio/bridge/sdk-core got added to this PR. Once you reset that we should be ok.

[brucearctor]

Fixed — force-pushed with the temporalio/bridge/sdk-core submodule reset. The PR now only touches the two intended files:

• temporalio/contrib/google_adk_agents/workflow.py
• tests/contrib/google_adk_agents/test_google_adk_agents.py

[brianstrauch]

Thank you!