fix: treat imports as potentially reactive

Author: Rich-Harris

.changeset/fuzzy-dancers-buy.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: treat imports as potentially reactive

packages/svelte/src/compiler/phases/2-analyze/visitors/Identifier.js

@@ -90,7 +90,8 @@ export function Identifier(node, context) {
 	if (binding) {
 		if (context.state.expression) {
 			context.state.expression.dependencies.add(binding);
-			context.state.expression.has_state ||= binding.kind !== 'normal';
+			context.state.expression.has_state ||=
+				binding.kind !== 'normal' || binding.declaration_kind === 'import';
 		}
 
 		if (

packages/svelte/tests/runtime-runes/samples/import-reactive/_config.js

@@ -0,0 +1,17 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: '<button>1</button> <button>2</button> <p>1</p>',
+
+	test({ assert, target }) {
+		const [btn1, btn2] = target.querySelectorAll('button');
+
+		flushSync(() => btn2.click());
+		assert.htmlEqual(target.innerHTML, `<button>1</button> <button>2</button> <p>2</p>`);
+
+		// reset state for next variant
+		flushSync(() => btn1.click());
+		assert.htmlEqual(target.innerHTML, `<button>1</button> <button>2</button> <p>1</p>`);
+	}
+});

packages/svelte/tests/runtime-runes/samples/import-reactive/main.svelte

@@ -0,0 +1,7 @@
+<script>
+	import { stuff } from './stuff.svelte.js';
+</script>
+
+<button onclick={() => Object.assign(stuff, { x: 1 })}>1</button>
+<button onclick={() => Object.assign(stuff, { x: 2 })}>2</button>
+<p>{Object.values(stuff)}</p>

packages/svelte/tests/runtime-runes/samples/import-reactive/stuff.svelte.js

@@ -0,0 +1 @@
+export const stuff = $state({ x: 1 });