fix(runtime): use block instead of stale b_block in reconcile_by_key Map path (#790)

Author: anubra266

packages/ripple/src/runtime/internal/client/for.js

@@ -450,7 +450,7 @@ function reconcile_by_key(anchor, block, b, render_fn, is_controlled, is_indexed
 						if (is_indexed) {
 							update_index(block, j);
 						}
-						update_value(b_block, b_val);
+						update_value(block, b_val);
 						++patched;
 					} else if (!fast_path_removal) {
 						destroy_block(a_blocks[i]);

packages/ripple/tests/client/for.test.ripple

@@ -173,6 +173,39 @@ describe('for statements', () => {
 		expect(container.querySelectorAll('.item').length).toBe(2);
 	});
 
+	it('keyed for with 32+ items: full reversal updates values via Map path', () => {
+		component App() {
+			let items = track(Array.from({ length: 40 }, (_, i) => ({ id: i, text: `Item ${i}` })));
+
+			<div>
+				for (let item of @items; index idx; key item.id) {
+					<span class="item">{idx + ':' + item.text}</span>
+				}
+			</div>
+
+			<button
+				onClick={() => {
+					@items = @items.toReversed();
+				}}
+			>
+				{'Reverse'}
+			</button>
+		}
+
+		render(App);
+
+		const getTexts = () => Array.from(container.querySelectorAll('.item')).map(
+			(el) => el.textContent,
+		);
+
+		expect(getTexts()).toEqual(Array.from({ length: 40 }, (_, i) => `${i}:Item ${i}`));
+
+		container.querySelector('button').click();
+		flushSync();
+
+		expect(getTexts()).toEqual(Array.from({ length: 40 }, (_, i) => `${i}:Item ${39 - i}`));
+	});
+
 	it('handles updating with new objects with same key', () => {
 		component App() {
 			let items = track([