view-composition

name	view-composition
description	Change or review UIKitPlus view composition internals inside the UIKitPlus source repository. Use for BodyBuilder, BodyBuilderItem, View+Body, View+Add, ForEach, stack insertion/removal, subscriptions, and composition diff behavior; not for ordinary downstream view construction.

Maintain UIKitPlus View Composition

Use this LOCAL contributor skill for built-in composition/runtime source work.

Load the smallest decision-complete context

1. Start from UIKitPlus AGENTS.md and SKILL_INDEX.md.
2. Use VIEW_COMPOSITION.md as the primary owner.
3. Add only the supporting contract the change needs:
   • RUNTIME_MODEL.md for insertion/update lifecycle;
   • MUTATION_MODEL.md for subscriptions/diff callbacks;
   • FLUENT_CHAIN_CONTRACT.md for changed public composition APIs.
4. Use SOURCE_MAP.md before broad source discovery.

Plan checklist

• Identify affected composition entrypoints such as body, addItem, add(views:at:), stack add paths, or ForEach.
• Classify the impact as DSL, runtime, or cross-layer.
• Identify subscription/diff handling changes and repeated-setup listener risk.
• Preserve explicit insertion/removal ordering and object identity.

Implementation rules

• Preserve reference/object identity; do not introduce value-view copy semantics.
• Keep insertion ordering explicit and consistent with current composition ownership.
• If changing ForEach subscriptions, keep begin/listener/end update flow and listener ownership explicit.
• Treat diff modifications handling as explicit policy; do not imply support that is not implemented.
• Do not add a second composition/runtime model to compensate for one local edge case.

Audit

Verify:

• fluent composition-facing chain continuity remains intact;
• ForEach insertions/deletions and any intentionally supported modifications remain safe;
• no hidden lifecycle regression appears in view/stack insertion/removal;
• repeated setup does not silently accumulate listeners/subscriptions;
• runtime docs change only if durable update timing/ownership actually changed;
• unrelated source/governance remains untouched.

Stop and re-plan if the work requires a new composition ownership/lifecycle mechanism rather than an implementation inside current UIKitPlus architecture.