* test(version-compat): keep GRPO fake-run logits finite on CPU
The GRPO fake-run test samples completions from a tiny untrained model on
CPU. Such a model can emit non-finite logits, so torch.multinomial inside
generate() intermittently raises "probability tensor contains either inf,
nan or element < 0" -- a nondeterministic sampling failure, not a regression
(the Trainer already fixes the seed, but CPU reduction order is not
bit-reproducible). Add a forward hook that sanitizes the LM head logits to a
finite bounded range before sampling, so the fake run reliably exercises the
whole train loop; the test checks the loop runs, not the numerics.
* [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
* test(version-compat): drop redundant nan_to_num bounds (clamp handles them)
* test(version-compat): scope GRPO finite-logits guard to the GRPO test
Only test_grpo_trains_on_cpu autoregressively samples completions, so it is
the only canary that can hit the non-finite-logits torch.multinomial crash.
Move the _guard_finite_logits hook out of the shared _load_plain() and into
test_grpo_trains_on_cpu so the SFT and DPO canaries keep asserting against the
model's true, unclamped logits.
---------
Co-authored-by: Daniel Han <unslothai@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
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