- table.c: unique shadow-check's candidate lookup now checks
wo_wal_repoint_offset1 before the durable wo_row_offset1, same as
back_off — a candidate updated earlier in the SAME uncommitted drain
was folded from its stale pre-update offset, letting a real @unique
clash through and committing a duplicate
- the offset-only substitution alone was NOT enough (verified): the
candidate must be FOLDED to compare values, and folding a pending
offset via pread saw "no record" (bytes still only in the staging
buffer), so the clash was still missed, just for a different reason
- wal.c: wo_wal_fold_row_at now reads a hop inside the currently-staged
region from `w->buf` (new scan_record_staged, scan_record's framing
over memory) instead of pread; every durable hop, and every existing
caller, is unchanged
- test_wal.c: two updates in one drain where the second collides with
the first's new unique value; must be refused. Verified failing
against the prior commit, and still failing with only the offset
substitution, before the fold fix; passing with both in place
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
(cherry picked from commit c049ab92570cfba4d12a018884a20b25a8916727)
shoney.arickathil
1f402ae4bb