The save-time simulation read the rules at READ COMMITTED without a lock,
so A -> B and B -> A written concurrently both passed. CheckRedirect,
AddressChanged and every batch now take a transaction-level advisory lock
before they read the rules.
- POST /_seo/api/v1/batch runs changes in one transaction: dry_run
answers the diff and the conflicts (loops, chains, noindex on a
published record, canonicals to redirected or noindex addresses) and
rolls back; a refused change refuses the batch (D-12)
- undo of a change or a whole batch from History and through MCP, with
the undo_stale, undo_loop and undo_gone refusals (D-13)
- CSV export and import of redirects, rules and records by URL: BOM,
comma or semicolon, formula cells escaped, a dry-run preview, all or
nothing with via import; the screen's apply token is HMAC-SHA256 over
the file and a fingerprint of the data (transfer.stale)
- Import and export singleton with the seo_transfer widget action,
History record actions undo and undo_batch, navigation entry
- MCP tools undo_change, undo_batch, apply_batch, export_csv, import_csv
- TestBatch, TestUndo, TestCSVTransfer, TestLoopRefused mcp and import
