fix: prevent UNINITIALIZED from leaking in get()

hmnd · hmnd · commit 2264941da32c · 2025-12-18T22:46:08.000-08:00
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
@@ -163,6 +163,10 @@ export function is_dirty(reaction) {
 	}
 
 	if (flags & DERIVED) {
+		// UNINITIALIZED deriveds need computation
+		if (/** @type {Derived} */ (reaction).v === UNINITIALIZED) {
+			return true;
+		}
 		reaction.f &= ~WAS_MARKED;
 	}
 
@@ -642,6 +646,10 @@ export function get(signal) {
 		throw signal.v;
 	}
 
+	if (signal.v === UNINITIALIZED) {
+		return /** @type {V} */ (undefined);
+	}
+
 	return signal.v;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -163,6 +163,10 @@ export function is_dirty(reaction) {`
`163`	`163`	`}`
`164`	`164`
`165`	`165`	`if (flags & DERIVED) {`
	`166`	`+ // UNINITIALIZED deriveds need computation`
	`167`	`+ if (/** @type {Derived} */ (reaction).v === UNINITIALIZED) {`
	`168`	`+ return true;`
	`169`	`+ }`
`166`	`170`	`reaction.f &= ~WAS_MARKED;`
`167`	`171`	`}`
`168`	`172`
`@@ -642,6 +646,10 @@ export function get(signal) {`
`642`	`646`	`throw signal.v;`
`643`	`647`	`}`
`644`	`648`
	`649`	`+ if (signal.v === UNINITIALIZED) {`
	`650`	`+ return /** @type {V} */ (undefined);`
	`651`	`+ }`
	`652`	`+`
`645`	`653`	`return signal.v;`
`646`	`654`	`}`
`647`	`655`