Revalidation is one call the app makes, and the policy stays with its holder

Status: accepted, 2026-10-05. Answers #18, and two points A handle keeps its fetch and derives its phase left open: whether a handle keeps the policy it was attached with, and the revalidation method. Serves The store is the UI's state and What earns a concept. Reopen a reachability input or a pacing setting when a stampede is measured that revalidate() and the sharing of a fetch in flight do not prevent.

Context#

Nothing refetched when an app returned to the foreground or regained its connection. #18 asked for a sweep of the stale and failed handles on an active scene, a retry of failed fetches when the network returns, an isReachable input, a revalidationSpread to pace the requests, and a platform observer by default.

invalidate() did two things: it marked everything stale and refetched the retained handles that were stale. The fetch policy was applied at an attach and then forgotten, so invalidate() refetched a handle attached storeOnly: one request before it, two after. A sweep that skips storeOnly handles could not be written while no handle remembered its policy.

Decision#

• One method. Environment.revalidate() refetches each retained operation whose data is stale or whose last fetch failed, where a holder allows the network, and marks nothing. A fetch in flight is not duplicated, and a handle with data does not pass through loading. "Whose last fetch failed" reads the handle's fetch value. The app calls it on its return to the foreground, and from its own path monitor if it has one.
• The policy is the holder's. An attach's policy stays with the retention it makes. A fetch the runtime starts later, for an invalidation, a revalidation or a heal, asks whether any holder of the root allows the network, so a storeOnly holder is fetched for by none of them. A storeOnly attach without data fails with MissingDataError, as it did.
• No timer. Staleness is the operation's @cacheExpiration(seconds:) or the store's default, read at an attach and by this call.

Evidence#

• e93ea3d built both. The tests in LifetimeTests.swift: "a storeOnly holder is fetched for by neither an invalidation nor a revalidation; a holder that allows the network is, while it holds", and "revalidate refetches a retained handle that is stale and one whose last fetch failed, leaves a fresh one alone, and marks nothing".
• The request count above, run against 97ddaa5 and reported on #18.

Not chosen#

• isReachable: a second input for a narrower predicate; a path that flaps wakes every screen. The app calls revalidate() from its path monitor.
• revalidationSpread: pacing belongs behind the transport, where an app can put a limit it shares with the rest of its networking.
• A platform observer by default: UIKit and AppKit lifecycle code inside the data layer. Environment.isActive parks subscriptions and is set by the app; queries read nothing of it.
• A trigger on the log's fetchStarted: a case or a field joins the log when an adopter shows a number it cannot derive, per The environment logs value-free events.