[PratikDhanave]

Link to Issue or Description of Change

Describe the change:

Problem:

_remove_any_of in src/google/adk/tools/_automatic_function_calling_util.py collapses a parameter's anyOf into a single schema on the Gemini (non-Vertex) function-declaration path used by build_function_declaration_for_langchain and build_function_declaration_for_params_for_crewai (i.e. LangChain / CrewAI tools).

Its comment says "Take the first non-null type", but the loop has no break and merges every non-null branch with property_schema.update(type_):

# Take the first non-null type.
if union_types:
  for type_ in union_types:
    if type_.get('type') != 'null':
      property_schema.update(type_)

For a heterogeneous union this has two wrong effects:

1. the last non-null branch wins instead of the first;
2. update() merges rather than replaces, so keywords from an earlier branch leak into the result, producing an invalid schema.

Example — a tool argument typed Union[List[str], int]:

# actual (before fix) — invalid: INTEGER type carrying the array-only `items`
type=INTEGER, items=Schema(type=STRING)

# expected — the first non-null member (list[str])
type=ARRAY, items=Schema(type=STRING)

Union[int, str] similarly yields STRING (the last member) instead of the documented first member INTEGER. Optional[T] is unaffected, because after _annotate_nullable_fields it has a single non-null branch.

Solution:

Add break after the first non-null branch is applied, so only the first non-null member is taken. This matches the function's own documented contract and produces a valid single-type schema. The common Optional[T] path is unchanged (single branch).

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

Added two regression tests to tests/unittests/tools/test_build_function_declaration.py:

• test_for_langchain_collapses_a_union_to_its_first_non_null_member
• test_for_crewai_collapses_a_union_to_its_first_non_null_member

Both fail on main (the first collapses to INTEGER with a stray items; the second collapses to the last member STRING) and pass with this change.

$ python -m pytest tests/unittests/tools/test_build_function_declaration.py \
    tests/unittests/tools/test_from_function_with_options.py \
    tests/unittests/tools/test_function_tool_with_import_annotations.py -q
131 passed in 0.53s

Fail-pre / pass-post for the new tests (fix reverted vs applied):

# fix reverted
2 failed      assert <Type.STRING> == 'INTEGER'
# fix applied
2 passed

Manual End-to-End (E2E) Tests:

Not run — this is a pure schema-generation fix with no runtime/UI surface; it is covered by the unit tests above.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules.