fix key block

packages/svelte/src/internal/client/dom/blocks/if.js

@@ -34,15 +34,12 @@ export function if_block(node, get_condition, consequent_fn, alternate_fn = null
 	/** @type {Effect | null} */
 	var alternate_effect = null;
 
+	/** We use a derived here to ensure stability of any depedencies due to the use of `pause_effect` */
 	var derived_condition = derived(() => !!get_condition());
 
 	var flags = elseif ? EFFECT_TRANSPARENT : 0;
 
 	block(() => {
-		// We use a derived here to ensure stability of any depedencies that are captured when we read `get_condition`.
-		// This is mainly because the current block effect's dependencies are only applied _after_ the effect has finished
-		// running, however as we're sync calling `destroy_effect` via `pause_effect` below, it might mean that our
-		// dependencies get lost. By having a derived already having run, those dependencies won't be affected by this
 		var condition = get(derived_condition);
 
 		/** Whether or not there was a hydration mismatch. Needs to be a `let` or else it isn't treeshaken out */

packages/svelte/src/internal/client/dom/blocks/key.js

@@ -1,7 +1,9 @@
 /** @import { Effect, TemplateNode } from '#client' */
 import { UNINITIALIZED } from '../../../../constants.js';
+import { derived } from '../../reactivity/deriveds.js';
 import { block, branch, pause_effect } from '../../reactivity/effects.js';
 import { safe_not_equal } from '../../reactivity/equality.js';
+import { get } from '../../runtime.js';
 import { hydrate_next, hydrate_node, hydrating } from '../hydration.js';
 
 /**
@@ -24,8 +26,11 @@ export function key_block(node, get_key, render_fn) {
 	/** @type {Effect} */
 	var effect;
 
+	/** We use a derived here to ensure stability of any depedencies due to the use of `pause_effect` */
+	var derived_key = derived(get_key);
+
 	block(() => {
-		if (safe_not_equal(key, (key = get_key()))) {
+		if (safe_not_equal(key, (key = get(derived_key)))) {
 			if (effect) {
 				pause_effect(effect);
 			}

packages/svelte/tests/runtime-legacy/samples/key-block-component-slot/_config.js

@@ -23,6 +23,6 @@ export default test({
 		button?.dispatchEvent(click);
 		flushSync();
 
-		assert.deepEqual(logs, ['mount', 'unmount', 'mount']);
+		assert.deepEqual(logs, ['mount', 'unmount']);
 	}
 });