Preserve iterable tool input examples across runner turns

[sylvesterkaczmarek]

Fixes #1990.

Materialize input_examples into a list when constructing BaseFunctionTool. Its sync and async wrappers can then serialize the same examples on every request instead of sharing a consumed iterator. None remains omitted and an empty iterable remains an empty list.

This captures iterable membership once without deep-copying individual example dictionaries. The helper's accepted parameter types, generated schema and actual function execution are unchanged.

Validation

Twenty-four public-client cases cover sync/async and streaming/non-streaming runners with generator, list-iterator, list, tuple, empty-iterator and omitted inputs. Each run executes one tool and makes two requests. Tests check both complete outgoing tool definitions, exact example values, Unicode content, input nonmutation, generator visitation and the tool-result message.

• Final regressions: 8 fail on unchanged main; all 24 pass with the fix, including sixteen controls.

• Related function, runner and eager-tool suites: 243 passed and one existing expected failure on both Python 3.10.16 and 3.14.7.

• The script's Pydantic v1 and optional MCP checks also passed, with unsupported Pydantic v1 cases skipped. Exact script summaries are recorded below.

• Repository formatting, complete ./scripts/lint and git diff --check passed.

• related310: 243 passed, 1 xfailed in 2.68s; 3 passed, 241 skipped in 2.62s; 39 passed in 2.51s

• related314: 243 passed, 1 xfailed in 3.15s; 39 passed in 4.16s

UV_PYTHON=3.10.16 TEST_API_BASE_URL=http://127.0.0.1:9 ./scripts/test tests/lib/tools/test_input_example_iterables.py tests/lib/tools/test_functions.py tests/lib/tools/test_runners.py tests/lib/tools/test_runner_eager_tools.py
UV_PYTHON='>=3.14.0' TEST_API_BASE_URL=http://127.0.0.1:9 ./scripts/test tests/lib/tools/test_input_example_iterables.py tests/lib/tools/test_functions.py tests/lib/tools/test_runners.py tests/lib/tools/test_runner_eager_tools.py
./scripts/lint

Tested on macOS arm64. Live services, other operating systems and the complete generated API runtime suite were not exercised. No dependencies, public signatures or release metadata changed.

[sylvesterkaczmarek]

The regression and related tests pass locally, with the validation details in the PR description. Could a maintainer approve the pending Actions run?