* Studio: warn when llama.cpp prebuilt is too old for MTP
Layered on #5527. Adds a one-shot llama-server --help capability probe
so users get a clear signal when their prebuilt is missing MTP support,
plus a graceful fallback if they load an MTP GGUF against an outdated
binary.
What's surfaced:
1. Startup log + stderr line in main.py:lifespan() if MTP isn't
advertised:
WARNING: llama.cpp prebuilt is missing MTP support
(--spec-type mtp / draft-mtp). Run `unsloth studio update` to
refresh it. MTP GGUFs will load without speculative decoding.
2. Load-time graceful fallback in load_model's spec block: skip the
auto-emit and log a clear warning instead of letting llama-server
fail with an unknown-flag error.
3. /api/inference/status now returns llama_cpp_supports_mtp: bool so
the frontend can show a banner / popup.
Probe internals:
- Class-level cache keyed on (binary_path, mtime). One subprocess call
the first time, instant thereafter. Touching the binary (e.g. via
`unsloth studio update`) invalidates the cache automatically because
the mtime changes, so the new build is picked up without restarting
the server.
- Recognises both upstream naming forms: the original draft-mtp from
llama.cpp PR #22673 and the renamed mtp variant in later commits.
- Spec block uses whichever token the binary accepts so we emit the
right value regardless of which release the user has.
Tests:
- 6 new cases in test_llama_cpp_mtp_detection.py covering each probe
variant (draft-mtp, renamed mtp, pre-MTP build, missing binary,
mtime-based cache invalidation).
- Existing 38 MTP detection cases still pass; broader 188-test
regression suite (server args, reload inheritance, gguf metadata,
load progress, context fit, model validation) still green.
* [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
---------
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
fc04809bfe