Automatic batching or startTransition for safe rollback of a schema-driven UI state change in React 18

Scenario

I have a React 18 app (concurrent renderer) where a single user action applies a "schema change" to local UI state: several components update their shape at once, driven by multiple setState calls, and a companion async fetch validates the new schema. If that fetch rejects, I want the UI to return to the previous consistent state rather than showing a half-migrated tree.

The trade-off

With automatic batching, all the updates commit in one render, which keeps the UI consistent, but I lose any intermediate loading state and I cannot tell whether the commit happened before or after the validation fetch settled. With startTransition, the update is interruptible and I can keep the old UI visible via isPending, but the scheduler decides when to yield, and if the async validation fails mid-transition there is no documented mechanism that guarantees the partially rendered work is discarded rather than committed.

Error boundaries only catch render-phase errors, and rejected promises inside a transition callback appear to bypass them, so the rollback path would have to be manual state restoration in a catch.

Questions

• For a multi-component state migration that must be all-or-nothing, is automatic batching or an explicit transition the documented safer choice?
• Is there any supported way to abort a pending transition from outside so the old committed tree stays on screen after a validation failure?
• Does the answer change between React 18.2 and 18.3 given the lane-priority behavior is version-dependent?