fix: iterate eager effects in reverse to avoid guards running out of order (#16795)

hmnd · hmnd · commit a4ccdfc9ab5d · 2025-10-11T02:38:52.000-07:00
diff --git a/packages/svelte/src/internal/client/reactivity/batch.js b/packages/svelte/src/internal/client/reactivity/batch.js
@@ -626,7 +626,8 @@ function flush_queued_effects(effects) {
 				// TODO this feels incorrect! it gets the tests passing
 				old_values.clear();
 
-				for (const e of eager_block_effects) {
+				// Update effects in reverse order to ensure outer guards are processed before their contents
+				for (const e of eager_block_effects.toReversed()) {
 					update_effect(e);
 				}
 

Original file line number	Diff line number	Diff line change
`@@ -626,7 +626,8 @@ function flush_queued_effects(effects) {`
`626`	`626`	`// TODO this feels incorrect! it gets the tests passing`
`627`	`627`	`old_values.clear();`
`628`	`628`
`629`		`- for (const e of eager_block_effects) {`
	`629`	`+ // Update effects in reverse order to ensure outer guards are processed before their contents`
	`630`	`+ for (const e of eager_block_effects.toReversed()) {`
`630`	`631`	`update_effect(e);`
`631`	`632`	`}`
`632`	`633`