The account merge predated the recent statistics additions and silently dropped
them:
- account_stats.moves and hints_used were not summed into the primary (the
secondary's row is read, then deleted), so the secondary's lifetime moves and
hints were lost.
- account_best_move was not handled at all; the secondary is only tombstoned
(not deleted), so its per-variant best moves lingered on the dead account and
never reached the merged statistics screen.
mergeStats now also sums moves + hints_used; a new mergeBestMoves folds the
secondary's best moves into the primary keeping the higher-scoring play per
variant (the rule the per-game upsert uses), then deletes the secondary's rows.
Profile fields were already correct (hint wallet summed, paid_account ORed; no
new accounts columns since).
Tests: TestAccountMergeCore extended — moves/hints summed, best moves merged
(higher score per variant kept), secondary rows cleaned up. Docs: ARCHITECTURE §4.
Ilia Denisov
developer