[kyleve]

Posted by an AI agent on kve's behalf.

Summary

Add scoped scroll restoration and shared Duo pose fixtures for adaptive UI. Stable views own navigation, presentation, and explicit reveal requests. This PR supplies groundwork; #372 integrates it into Where.

Ownership and APIs

API	Responsibility
SnapshotConfiguration.DuoPose	Seven synthetic poses, localized labels, existing frames/traits, and typed reserved-region geometry with activation state.
BScrollRestorationStore and .bScrollRestorationScope()	Retain entries by view type and typed role within an explicit stable scene/session scope. Context changes replace an entry rather than retaining historical contexts.
BScrollPosition<ID, Context>	Supply a native scroll binding, semantic commands, retained alignment, and initialization after content loads. Keep context typed until the heterogeneous store boundary.
AdaptivePaneGeometry and AdaptivePaneArrangement	Map physical container geometry and resolve compact, columns, or tabletop using stylesheet limits.

The store retains semantic content identity and alignment, without pixel restoration, persistence, application navigation, or pane synchronization. Without a scope, positions remain view-local. Consumers choose readiness, initial positioning, validity, and fallback behavior.

A pending initialization cannot replace a later user position. Old bindings and outgoing views retain detached entries after context replacement. Reading an unmounted wrapper asserts in debug; release access uses an isolated attachment that cannot claim a scoped entry.

Where has no shared selection coordinator. #372 keeps a small month-reveal value in Locations and gives Timeline its own row IDs. RegionStint.ID is a typed Hashable/Sendable region/start-date identity; this source API change does not alter persisted data.

AdaptivePaneGeometryReader also supports the welcome and developer overlays. It does not implement navigation bars or toolbars. Native containers retain that responsibility. Broadway supplies column-card styling, and the architecture rule confines system reserved-region reads to the geometry adapter.

Duo fixtures retain their frame names, dimensions, traits, snapshot identifiers, and measurement provenance. SnapshotKit owns the labels; WhereUI adapts its reserved-region values to production geometry.

Composition

@BScrollPosition<CalendarPresentationState.Target, ScrollContext>
private var detailPosition: ScrollPosition

// In the view initializer:
_detailPosition = BScrollPosition(
    Self.self,
    role: scrollRole,
    context: { ScrollContext(region: focusedRegion, year: report.selectedYear) },
    idType: CalendarPresentationState.Target.self,
)

The consumer in #372 places .bScrollRestorationScope() on a stable ancestor and binds the scroll view to $detailPosition. Once content is ready, initialize(id:anchor:) restores the saved target or applies that view's initial policy.

Review focus

• BScrollPosition and its mounted tests: replacement, typed contexts, independent roles/scopes, stale bindings, and delayed readiness.
• DuoPose: shared labels and unchanged geometry/identifiers.
• AdaptivePaneGeometry: physical reserved-region coordinates, asymmetric insets, and RTL. The policy tests cover minimum readable pane sizes.
• Independent review found no actionable issue in the final foundation or affected consumer contracts. Release fallback isolation was source-inspected, not executed by debug tests.

Testing

• Focused foundation validation passed 12 tests: mounted BScrollPosition, SnapshotDuoPose, and AdaptivePaneContainer.
• ./test BroadwayUITests SnapshotKitTests WhereUITests passed all 29 BroadwayUI and 58 SnapshotKit tests. Its 711 WhereUI tests found four calendar binding-observation failures and one new timeline test waiting on a transient command; all five were corrected and the rebuilt 19-test mounted regression set passed.
• The affected seven screen snapshot suites passed across the broad run and focused final revalidation, using --record never --review. This review follow-up updates five reviewed accessibility legends in feat(WhereUI): adapt Where for iPhone Duo #372 and removes one obsolete linked-timeline capture; screen pixels in those five updated captures are unchanged.
• Architecture checks passed 29 tests. Default host checks, ./swiftformat --lint, ./xcstrings --lint, and complete PR diff checks passed.
• Mounted tests cover replacement, delayed alignment, context reset, stale callbacks, independent roles/scopes, and operation without a scope. Release-only fallback behavior was source-inspected; real touch gestures remain a separate runtime limit.

Native Duo 27.2 geometry measurement remains pending. Synthetic layouts and hosted state tests do not establish native folding, system-bar placement, keyboard behavior, or spoken VoiceOver behavior.

Stack

First active layer, based on main after #377 merged. #372 adds consumer integration. Both PRs remain open for review.

Backlog reconciliation

The 13 preserved Duo records are tracked in Linear. STU-318 owns adoption and its six implementation sub-issues. This slice relates to STU-321, STU-324. Unmerged implementation remains In Review.

Remaining Backlog work: native Duo release validation (STU-316), intermittent Locations settling diagnostics (STU-317), and tall Year accessibility annotations (STU-325). Existing STU-114 and STU-252 now distinguish the partial fixes from their remaining requirements; both retain their priorities, labels, and open state.

[kyleve]

If this is only for testing, maybe we should move it into SnapshotKit itself?

[kyleve]

Posted by an AI agent on kve's behalf.

Moved the seven synthetic configurations into SnapshotConfiguration.Pose in cb30be5. They reuse the existing frames and traits and carry typed reserved-region geometry plus activation state. WhereUI keeps the localized lab labels and its geometry adapter. Frame names, dimensions, snapshot IDs, and measurement provenance are unchanged; native 27.2 re-measurement remains pending.

[kyleve]

Similar question; is this duplicated with anything in SnapshotKit?

[kyleve]

Posted by an AI agent on kve's behalf.

Removed the separate pose geometry definitions in cb30be5. SnapshotKit now owns each synthetic pose and its reserved regions; WhereUI adapts those values to the production geometry API. AdaptiveHistoryGeometry remains in WhereUI because it interprets the container and system geometry for application layout.

[kyleve]

Does "remount" here mean as the UI moves around as the device is folded, unfolded, rotated, etc?

I wonder if there's a more general way to support this for scrollable areas that have anchors for content; I gotta imagine this is more common than just calendars.

[kyleve]

Eg, imagining something like:

• At the level of a stable container, place a ScrollPosition cache in the Environment
• The positions are cached by the view type, and some identifier (eg, like the region)
• Upon remounting the view, look up a scroll position value / write it up on scroll.

This would be a more general solution to the mount/remount problem than making a model for each view type.

[kyleve]

Posted by an AI agent on kve's behalf.

Yes—replacement as a fold or layout branch changes. Implemented your stable-ancestor environment approach in cb30be5 and 9b386b5: .bScrollRestorationScope() owns a BScrollRestorationStore, and @BScrollPosition supplies a native binding keyed by view type and typed pane role. Region/year is a separate context token that replaces the current entry, so there is no history of old contexts. Without a scope it stays view-local. Mounted tests cover replacement, independent scopes/roles, delayed readiness, obsolete callbacks, and bottom alignment. #372 uses it for calendar detail, timeline, and Locations browsing.

[kyleve]

Yeah similar comment to CalendarNavigationModel; this feels much more generalizable than we've made it here.

[kyleve]

Posted by an AI agent on kve's behalf.

Agreed. cb30be5 removes scroll storage from the history coordinator. HistorySelectionModel now holds only the selected interval and explicit reveal requests, with distinct request IDs and independent consumption by each destination. Ordinary scrolling does not change the linked selection. The shared Broadway utility owns restoration; #372 integrates it and tests delayed data and repeated reveals.

[kyleve]

Yeah another one where IMO at least the scroll position stuff can be generalized.

[kyleve]

Posted by an AI agent on kve's behalf.

Generalized in cb30be5 / 9b386b5 and integrated in #372 (cde4ff4). Timeline uses the same @BScrollPosition as calendar and Locations, with its own typed role and year context. The remaining timeline-specific code resolves explicit history selections against loaded domain items; it also retries when an existing stay extends without changing its ID.

[kyleve]

I don't 100% love this approach; what exactly is it solving? Why do we need this state when we didn't need it before; can the view itself not keep our navigation state like it did before?

[kyleve]

Posted by an AI agent on kve's behalf.

Removed the aggregate SceneNavigationModel approach. cb30be5 supplies the reusable groundwork; cde4ff4 in #372 keeps paths, selection, search, sheets, and presentation helpers in stable owning views above adaptive branches. Models interpret data and access preferences. Editors keep their drafts locally, and an active pushed Locations stack remains mounted while resizing; tabletop waits until returning. Hosted guards cover pushed-controller identity, search, presented editors, unsaved drafts, and load continuity. Native keyboard/focus and physical folding validation remain pending.

[kyleve]

Confirming we want this and not a more specific type?

[kyleve]

Posted by an AI agent on kve's behalf.

Addressed in 4acf65c. BScrollPosition<ID, Context> retains the concrete Hashable context in its closure and mount. Type erasure now happens only when crossing into the heterogeneous restoration store. #372 migrates every consumer and test probe.

[kyleve]

I think this should be an assert so it doesn’t crash in prod

[kyleve]

Posted by an AI agent on kve's behalf.

Addressed in 4acf65c. Unmounted access uses assertionFailure in debug and returns a stable, isolated attachment in release. That fallback never resolves the environment store, so it cannot replace a mounted entry. Mounted/context-isolation tests pass; the release-only fallback was source-reviewed rather than executed by the debug suite.

[kyleve]

Maybe we name this duo pose?

Also, one case per case statement please?

[kyleve]

Posted by an AI agent on kve's behalf.

Addressed in eb9dd29: renamed the type and matching files to SnapshotConfiguration.DuoPose, with one enum case per declaration. The frames, traits, reserved regions, activation state, and snapshot identifiers are unchanged.

[kyleve]

any reason to not put these strings in snapshotkit too?

[kyleve]

Posted by an AI agent on kve's behalf.

Addressed in eb9dd29. SnapshotKit now owns the seven localized pose labels and its resource catalog. WhereUI retains only the production geometry adapter; the label text is unchanged.

[kyleve]

I wonder if we could simplify this by just giving each element we want to scroll to a more regular id? This feels very complicated to me

[kyleve]

Posted by an AI agent on kve's behalf.

Simplified in 7aa3146 and the #372 integration commit 4c0cd0a. Removed PresenceSelectionModel, per-pane consumption tracking, the timeline resolver, and the unused linked presentation. Timeline now owns its recorded/flight/planned row IDs. Locations owns a small CalendarMonthReveal value passed through @Binding; its request identity remains distinct from the month identity so selecting the same month again works after loading. Mounted tests cover delayed/repeated requests and browsing restoration without replaying a consumed request. Those tests caught a plain-binding observation gap during the refactor; registering the value with @Binding fixes it. Five annotation references in ca09946 remove the obsolete recorded-row Button trait; their screen pixels are unchanged, and planned-stay buttons remain.

[kyleve]

What exactly is custom chrome? Why do we need it?

[kyleve]

Posted by an AI agent on kve's behalf.

Clarified in fd1fd30, with the Settings simplification in #372 commit 0790712. The geometry reader is reused by the welcome and developer overlays to find clear space. It does not draw navigation bars or toolbars. Settings now uses native split navigation and stylesheet compact policy directly; Locations retains the pane resolver for its tabletop composition. Native Duo geometry validation remains pending.