[fix] don't run binding init unnecessarily (#7981)

Author: dummdidumm

src/compiler/compile/render_dom/wrappers/InlineComponent/index.ts

@@ -393,7 +393,7 @@ export default class InlineComponentWrapper extends Wrapper {
 
 			component.partly_hoisted.push(body);
 
-			return b`@binding_callbacks.push(() => @bind(${this.var}, '${binding.name}', ${id}));`;
+			return b`@binding_callbacks.push(() => @bind(${this.var}, '${binding.name}', ${id}, ${snippet}));`;
 		});
 
 		const munged_handlers = this.node.handlers.map(handler => {

src/runtime/internal/Component.ts

@@ -5,11 +5,13 @@ import { children, detach, start_hydrating, end_hydrating } from './dom';
 import { transition_in } from './transitions';
 import { T$$ } from './types';
 
-export function bind(component, name, callback) {
+export function bind(component, name, callback, value) {
 	const index = component.$$.props[name];
 	if (index !== undefined) {
 		component.$$.bound[index] = callback;
-		callback(component.$$.ctx[index]);
+		if (value === undefined) {
+			callback(component.$$.ctx[index]);
+		}
 	}
 }
 

test/runtime/samples/binding-no-unnecessary-invalidation/Tab.svelte

@@ -0,0 +1,3 @@
+<script>
+	export let tab;
+</script>

test/runtime/samples/binding-no-unnecessary-invalidation/_config.js

@@ -0,0 +1,7 @@
+export default {
+	async test({ assert, target }) {
+		assert.htmlEqual(target.innerHTML, `
+			<p>0</p>
+		`);
+	}
+};

test/runtime/samples/binding-no-unnecessary-invalidation/main.svelte

@@ -0,0 +1,17 @@
+<script>
+	import { writable } from "svelte/store";
+	import Tab from "./Tab.svelte";
+
+	let i = 0;
+	const { set, subscribe } = writable({ id: 1, name: "tab1" });
+	const tab = {
+		set(value) {
+			i++;
+			set(value);
+		},
+		subscribe,
+	};
+</script>
+
+<Tab bind:tab={$tab} />
+<p>{i}</p>