Import wiredtiger: 5e6daf7d42727e3d86b2603c20852d1426dee55f from branch mongodb-4.4

ref: 5199f7f394..5e6daf7d42
for: 4.4.0-rc11

WT-6457       Restore static testing that zero-length row-store values are never written
WT-6464       Fix memory leak in __rollback_row_add_update

1 files changed, 13 insertions, 3 deletions

diff --git a/src/third_party/wiredtiger/src/txn/txn_rollback_to_stable.c b/src/third_party/wiredtiger/src/txn/txn_rollback_to_stable.c
index 9be945bb6c3..afc3508e577 100644
--- a/src/third_party/wiredtiger/src/txn/txn_rollback_to_stable.c
+++ b/src/third_party/wiredtiger/src/txn/txn_rollback_to_stable.c
@@ -94,9 +94,10 @@ __rollback_row_add_update(WT_SESSION_IMPL *session, WT_PAGE *page, WT_ROW *rip,
 {
     WT_DECL_RET;
     WT_PAGE_MODIFY *mod;
-    WT_UPDATE *old_upd, **upd_entry;
+    WT_UPDATE *last_upd, *old_upd, **upd_entry;
     size_t upd_size;
 
+    last_upd = NULL;
     /* If we don't yet have a modify structure, we'll need one. */
     WT_RET(__wt_page_modify_init(session, page));
     mod = page->modify;
@@ -108,9 +109,13 @@ __rollback_row_add_update(WT_SESSION_IMPL *session, WT_PAGE *page, WT_ROW *rip,
     upd_entry = &mod->mod_row_update[WT_ROW_SLOT(page, rip)];
     upd_size = __wt_update_list_memsize(upd);
 
+    /* If there are existing updates, append them after the new updates. */
+    for (last_upd = upd; last_upd->next != NULL; last_upd = last_upd->next)
+        ;
+    last_upd->next = *upd_entry;
+
     /*
-     * If it's a full update list, we're trying to instantiate the row. Otherwise, it's just a
-     * single update that we'd like to append to the update list.
+     * We can either put a tombstone plus an update or a single update on the update chain.
      *
      * Set the "old" entry to the second update in the list so that the serialization function
      * succeeds in swapping the first update into place.
@@ -131,7 +136,12 @@ __rollback_row_add_update(WT_SESSION_IMPL *session, WT_PAGE *page, WT_ROW *rip,
      */
     WT_ERR(__wt_update_serial(session, NULL, page, upd_entry, &upd, upd_size, true));
 
+    if (0) {
 err:
+        if (last_upd != NULL)
+            last_upd->next = NULL;
+    }
+
     return (ret);
 }