* Studio: gracefully disable MTP when the model has no head or drafter
Selecting MTP or MTP+Ngram in Speculative Decoding on a GGUF with no nextn
head and no separate drafter aborted the whole load. llama-server does not
no-op an empty draft-mtp request: it exits with 'failed to measure MTP
context memory: failed to create llama_context', surfaced to the user as a
generic 'llama-server failed to start. Check that the GGUF file is valid
and you have enough memory.'
Build-time fix in _build_speculative_flags: when a forced mtp / mtp+ngram
mode targets a model with no MTP head and no drafter (is_mtp_model is
False), default back instead of emitting draft-mtp. mtp falls back to
--spec-default; mtp+ngram keeps the ngram-mod half, which needs no head.
Real MTP models (embedded head or separate drafter), sub-3B MTP overrides,
and the auto path are unchanged.
Runtime hardening: the existing post-launch MTP retry only fired for
separate-file drafters (--model-draft in spec_flags), so an embedded-head
model that the binary cannot build still hard-failed. Gate the retry on the
spec block requesting MTP, recognise the embedded-head abort strings
('failed to measure MTP context memory', 'failed to create llama_context'),
and make the drafter name None-safe in the warning.
Tests: extend the resolver matrix (forced mtp / mtp+ngram on a non-MTP
model) and add two cases asserting the default-back emission.
* [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
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Co-authored-by: danielhanchen <michaelhan2050@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
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