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Pieter De Baets
c1d8ae970d
Summary: Pull Request resolved: https://github.com/react/react-native/pull/57328 Today the iterator-setter path in `ConcreteComponentDescriptor::cloneProps` runs three sequential walks over the input — `RawProps::parse(parser)` (builds `keyIndexToValueIndex_` for `convertRawProp`), `static_cast<folly::dynamic>(rawProps)` (materializes a `folly::dynamic` via `jsi::dynamicFromValue` in JSI mode), and then `dynamic.items()` to dispatch `setProp`. Only the third is actually used: `convertRawProp` is never called on the iterator-setter branch, and the `folly::dynamic` materialization exists only as iteration scaffolding. Restructure so the runtime flag picks one of two construction paths up front: - **Iterator-setter** — copy-construct from `sourceProps` via the (re-enabled) `Props` copy ctor, then walk `rawProps` in-place via the new `RawProps::forEachItem` helper and route each entry through `setProp`. `parse()` is skipped entirely; the `folly::dynamic` materialization is skipped in `Mode::JSI`. - **Classic** — unchanged: `parse()` + 3-arg `convertRawProp`-driven ctor. `forEachItem` switches on `RawProps::Mode`: - `Mode::JSI` — walks `value_.asObject(*runtime_).getPropertyNames(...)` and constructs `RawValue` from each `jsi::Value` directly, no `folly::dynamic` in between. - `Mode::Dynamic` — iterates `dynamic_.items()` (same as today). - `Mode::Empty` — no-op. A new `HasIteratorSetterCtor<T>` concept (`std::copy_constructible<T>`) documents the contract and feeds a `static_assert` in `cloneProps`, so a future Props type that deletes its copy ctor fails at compile time rather than silently diverging at runtime between the two flag states. The `RN_SERIALIZABLE_STATE` Props 2.0 accumulation branch keeps its existing dynamic-iteration shape — when `fallbackToDynamicRawPropsAccumulation` is true, `initializeDynamicProps` has already merged the source's rawProps with the input onto `shadowNodeProps->rawProps`, so we iterate that merged dynamic rather than the raw input. The per-field `flag ? sourceProps.X : convertRawProp(...)` ternaries across every Props .cpp file become dead in the flag-on path (the copy ctor handles those fields) but are still functional in the flag-off path. They get removed in a follow-up cleanup; this diff is structurally non-breaking on either flag state. Changelog: [Internal] Reviewed By: zeyap Differential Revision: D109568749 fbshipit-source-id: eae20478418a7dbf7364c73d85d7694d99f1e8f1