langchain

19ddd428 - fix(ollama): raise error when clients are not initialized (#35185)

fix(ollama): raise error when clients are not initialized (#35185) ## Summary - When `self._client` is `None` in `_create_chat_stream()`, the method silently produces an empty generator instead of failing. - The error only surfaces later as a misleading `"No data received from Ollama stream"` ValueError, making it difficult to diagnose the actual root cause (uninitialized client). - Changed to raise `RuntimeError` immediately with a clear message when the sync client is not initialized. ## Why this matters Users who hit this path see a confusing error message that points them in the wrong direction. An explicit error at the point of failure makes debugging straightforward. ## Test plan - [x] Added `test_create_chat_stream_raises_when_client_none` - [x] Existing tests still pass > This PR was authored with the help of AI tools. --------- Co-authored-by: Mason Daugherty <github@mdrxy.com>