Benson Wang 32ee07df01 fix: prompt token may be None in streaming mode ...

Merge https://github.com/google/adk-python/pull/3462

**Please ensure you have read the [contribution guide](https://github.com/google/adk-python/blob/main/CONTRIBUTING.md) before creating a pull request.**

### Link to Issue or Description of Change

**1. Link to an existing issue (if applicable):**

- Closes: #_issue_number_
- Related: #_issue_number_

**2. Or, if no issue exists, describe the change:**

**Problem:**
When using adk in streaming mode, `usage_metadata.prompt_token_count` may be `None` which will emit log
```Invalid type NoneType for attribute 'gen_ai.usage.input_tokens' value. Expected one of ['bool', 'str', 'bytes', 'int', 'float'] or a sequence of those types```

**Solution:**
Skip setting span attribute if prompt token count is None

**Unit Tests:**

- [x] All unit tests pass locally.

_Please include a summary of passed `pytest` results._

### Checklist

- [x] I have read the [CONTRIBUTING.md](https://github.com/google/adk-python/blob/main/CONTRIBUTING.md) document.
- [x] I have performed a self-review of my own code.
- [x] I have commented my code, particularly in hard-to-understand areas.
- [x] I have added tests that prove my fix is effective or that my feature works.
- [x] New and existing unit tests pass locally with my changes.
- [x] I have manually tested my changes end-to-end.
- [x] Any dependent changes have been merged and published in downstream modules.

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/3462 from wsa-2002:prompt-token-count-may-be-none-in-streaming-mode 94666862f70ed2577d5c55485e67f6da36a57bc6
PiperOrigin-RevId: 867693355

2026-02-09 11:24:22 -08:00

..

integration

chore: Upgrade to headers to 2026

2026-01-20 14:50:09 -08:00

unittests

fix: prompt token may be None in streaming mode

2026-02-09 11:24:22 -08:00

__init__.py

chore: Upgrade to headers to 2026

2026-01-20 14:50:09 -08:00