* chat : reject JSON nested more than 128 levels before walking it
The schema builder, the jinja engine and the decision code walk request
JSON with recursion. A request nested deep enough overflows the stack of
the HTTP thread and llama-server dies (SIGBUS on macOS, SIGSEGV on Linux):
for a tool schema from a few hundred levels on macOS and about 10000 on
Linux.
Check the depth first and answer 400 past 128 levels: the chat inputs in
common_chat_templates_apply (tools, tool-call arguments,
chat_template_kwargs, json_schema), the json_schema of /completion, and the
whole /v1/systemone body. A gemma4 tool result that is too deep stays text.
* fix the root, not the call side
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Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
