fix(pflash): tighten drafter tail-capture view-bounds guard (bug #42)#356
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…-Org#42) Old guard `tail_lo < cs + cl` fires when S%chunk_size ∈ {1..7}, passing a ggml_view_3d that overruns the chunk by up to 7 rows (deterministic assert). New guard `tail_lo + n_lookahead <= cs + cl` rejects straddlers. 5 pure-arithmetic unit tests cover the boundary: T1 RED→GREEN, T2-T4 stable.
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…FAIL) Bug-repro binary test_drafter_tail_capture_guard_red was compiled but never registered; CI could not enforce that the old guard reproduces the failure.
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Re-carved from #274 as a standalone fix off current
main(extracted from multi-feature commit51ea345; the ee7 drafter changes are a later PR).The drafter's tail-capture guard used
tail_lo < cs + cl, which admits a view whosen_lookaheadrows overrun the chunk whentail_lolands in a chunk's lastn_lookaheadrows — a deterministicggml_view_3dassert at S%4096 in {1..7}. Tightened totail_lo + n_lookahead <= cs + clat both capture sites (qwen3_graph.cpp:419,:469).Added
test_drafter_tail_capture_guard.cpp(boundary test). Red→green: reproduces the overrun at S=4097/r=1 with the old guard; all 7 boundary cases + cross-chunk cases pass with the fix. 3 files, +143/-2.