The chat-template loader only read the `chat_template` field from
tokenizer_config.json. Qwen3.6-27B ships its vision-aware template
*only* in a standalone `chat_template.jinja` (and has no
tokenizer_config.json at all), so the loader returned None and image
requests fell back to the text-only format_qwen3_prompt — rendering
zero `<|image_pad|>` tokens and tripping
"expand_image_pad_tokens: prompt has 0 image_token_id occurrences".
load_chat_template_alongside now follows HF transformers precedence:
standalone chat_template.jinja → chat_template.json → the
chat_template field in tokenizer_config.json. Tests cover the
precedence, the text-only fallback, and that an OpenAI image_url
content part renders `<|image_pad|>` through the real template
condition (`'image_url' in item`).
Refs #16 / TP-vision.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
rob thijssen
7ad56c6a86
