breaking: always run pre effects synchronously (#10928)

Author: Rich-Harris

.changeset/few-clouds-shop.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+breaking: always run pre effects immediately

packages/svelte/src/internal/client/reactivity/effects.js

@@ -142,9 +142,8 @@ export function pre_effect(fn) {
 					: '')
 		);
 	}
-	const sync = current_effect !== null && (current_effect.f & RENDER_EFFECT) !== 0;
 
-	return create_effect(PRE_EFFECT, fn, sync);
+	return create_effect(PRE_EFFECT, fn, true);
 }
 
 /**
@@ -206,7 +205,7 @@ export function render_effect(fn, managed = false) {
 	let flags = RENDER_EFFECT;
 	if (managed) flags |= MANAGED;
 
-	return create_effect(flags, /** @type {any} */ (fn), true);
+	return create_effect(flags, fn, true);
 }
 
 /**

packages/svelte/tests/runtime-runes/samples/pre-effect-ordering/_config.js

@@ -19,14 +19,14 @@ export default test({
 
 		assert.deepEqual(log, [
 			'Outer Effect Start (0)',
-			'Outer Effect End (0)',
 			'Inner Effect (0)',
+			'Outer Effect End (0)',
 			'Outer Effect Start (1)',
-			'Outer Effect End (1)',
 			'Inner Effect (1)',
+			'Outer Effect End (1)',
 			'Outer Effect Start (2)',
-			'Outer Effect End (2)',
-			'Inner Effect (2)'
+			'Inner Effect (2)',
+			'Outer Effect End (2)'
 		]);
 	}
 });