Explicit `position_ids` passed to `generate()` crash on the first decoding step under Transformers 4.57.6. The generation loop keeps the prompt-length positions, while `prepare_inputs_for_generation()` indexes the next cache position beyond their end.
Extend explicit positions after generation updates only when the parent implementation leaves them unchanged. Preserve each row's final position and advance by the actual number of accepted tokens. Transformers 5.22.1 already extends positions, so it retains its existing behavior.
Validation:
- Seven new tests pass under both Transformers 4.57.6 and 5.22.1. All seven fail under 4.57.6 before this fix.
- Coverage includes cached and uncached decoding, left padding, custom per-row positions, beam search, multi-token updates, and caller-input preservation. Generation is checked against independent full-forward decoding.
- Existing 65-case suites introduce no additional failures: 4.57.6 has 62 passes, 2 known unrelated failures and 1 skip; …
- Fix generate() and attention masking under Transformers 5.x (b9e4394ccce54f7206da4358cd7987cb57efd893)
- Add DFlash2 inference fixes (warm-cache verify mask, logits_to_keep, chunked MLP) (c4bb0c1fad49ddce9de8cf9849e2d7ffa3b660f0)
- Rename MLP chunk env var to RIPPLE_MLP_CHUNK (c178f879bfc6a52f93f9adb467478193ec3689b7)
- Fix StaticCache causal mask and labels+logits_to_keep loss (8662efad14a490205c62dc795ecfd70c46807aff)
- Fix StaticCache causal mask and labels+logits_to_keep loss (2c3501bf7bf0d4f4eed89a5b417524f138d83091)
- fix(ricursive): mask from actual cache positions; keep labeled loss with logits_to_keep (0d2fa09828767ed003d41a8df08ad377d7b0ea17)
- Align the causal mask to the keys the layer holds and forward cache positions (ee974ea44fc20eb18134822bbd80e9ea1a0989ca)
Co-authored-by: Qubitium <Qubitium@users.noreply.huggingface.co>
