Summary

Two WT_ASSERT_ALWAYS calls in __rec_validate_upd_chain require that prev_upd->upd_durable_ts >= vpack->tw.durable_(stop,start)_ts. This invariant is violated when an obsolete-check pass removes a globally-visible tombstone: the re-inserted update now legitimately sits at a lower timestamp than the on-disk durable_ts it supersedes. The start_ts assert in the same function already has the __wt_txn_upd_visible_all escape; the two durable_ts asserts are missing it, causing spurious assertion failures.

Impact

Spurious assertion failure (see also BF-42097). Not a data integrity issue. Affects develop generally.

File

• src/reconcile/rec_visibility.c

Fix

Add the __wt_txn_upd_visible_all escape to both durable_ts assert sites:

// src/reconcile/rec_visibility.c — two assert sites
 WT_ASSERT_ALWAYS(session,
   ... || prev_upd->upd_durable_ts >= vpack->tw.durable_stop_ts
+  || __wt_txn_upd_visible_all(session, prev_upd),
   ...);

 WT_ASSERT_ALWAYS(session,
   ... || prev_upd->upd_durable_ts >= vpack->tw.durable_start_ts
+  || __wt_txn_upd_visible_all(session, prev_upd),
   ...);

Notes

Discovered during development on the WT-16973 clean-scrub eviction branch (PR #13605). Fix is independent of that feature and should be applied directly to develop.