Make Perception runtime checking opt-in

[johnnewman-square]

Perception's debug-only runtime check reports Store state read from a view body that isn't wrapped in WithPerceptionTracking. That modifier is required for observation to work below iOS 17, but unnecessary at iOS 17 and above, where native Observation tracks the read on its own. The check can't tell those two situations apart, so on 17 and above it reports reads that are already working correctly.

#393 made suppression available as an opt-out, which was the right call while clients were still on iOS 16 — a warning there is diagnosing something real. As clients bump to 17, the default has become a recurring cost instead.

Summary

• Rename Runtime.Configuration.suppressPerceptionCheckingWhenUsingObservation to enablePerceptionChecking, defaulting to false
• Remove the availability gate on the suppression funnel
• Remove the Xcode preview special case, along with the XcodePreviews type and its tests
• Invert the two StoreTests cases to cover the new default and the opt-in

This is a breaking change — a source-breaking rename plus a behavior change for every client — so it wants a major version bump.

Why rename rather than flip the default

A bare default flip leaves the flag named suppress…, so a client that wants the check writes suppressPerceptionCheckingWhenUsingObservation = false. A double negative at the one call site whose whole purpose is to say "yes, I want this" works against the change. The default flip is behaviorally breaking on its own, so the major bump is already owed; the rename rides along and leaves the API reading the way it behaves.

Why the availability gate goes away

The old funnel only suppressed at iOS 17 and above, inferring from the OS version whether a warning was worth showing. An explicit opt-in states the same thing directly and more accurately — a client knows its own deployment target, and can decide for itself.

Why the preview special case goes away

#396 detected the preview process and suppressed unconditionally, on the reasoning that a preview can't opt in for itself. That reasoning was half right, and I'd like to correct it here since it's load-bearing for this change: Runtime.withConfiguration(override:operation:) is a task local, so a binding placed around a #Preview body-producing closure is indeed gone by the time SwiftUI evaluates that body. But Runtime.updateDefaultConfiguration writes a process-global instead, so it survives past the call and a preview can use it:

#Preview {
    let _ = Runtime.updateDefaultConfiguration { $0.enablePerceptionChecking = true }
    MyWorkflow().workflowPreview()
}

So a preview was never actually locked out — it just had boilerplate to write. With the check off by default, it doesn't even need that: a preview gets quiet behavior from the default itself, and the one thing it can no longer do is have the check forced off against an explicit opt-in. Previews now follow the same configuration as everything else rather than overriding it, which is the outcome worth having.

XcodePreviews had no other consumer, so it and its tests are deleted rather than left orphaned.

What stays

The withPerceptionCheckSuppressed wrapping of PreviewView's representable callbacks, added in #396. That isn't a preview exception — it's the only thing routing a workflow's reads of its own state through the configuration, since those reads never pass through a Store. Remove it and a render pass would be checked regardless of what the configuration says.

The cost, stated plainly

Below iOS 17 this is a real loss of signal. An untracked read there is a genuine defect rather than a false positive: without WithPerceptionTracking, a view does not update when the state it reads changes. A client on iOS 16 that doesn't know to opt in now gets a silently non-updating view and no diagnostic pointing at why.

Test plan

• tuist test --path Samples UnitTests --test-targets WorkflowSwiftUI-Tests — 47/47, including both inverted cases: test_perceptionRuntimeWarningsAreDisabledByDefault (no override, asserts the check is quiet) and test_perceptionRuntimeWarningsWhenCheckingIsEnabled (opts in, asserts the check fires)
• swift build across the whole package — the rename is a public property in the core Workflow module, and nothing else referenced it
• swiftformat --lint clean
• Verified in a live preview canvas — relying on CI plus the unit coverage above

Test count drops from 51 to 47 because the four XcodePreviewsTests are deleted with the type they covered.

Checklist

• Unit Tests
• UI Tests (not applicable)
• Snapshot Tests (not applicable)
• I have made corresponding changes to the documentation