fix: special value handling

packages/svelte/src/compiler/phases/3-transform/client/visitors/RegularElement.js

@@ -212,7 +212,8 @@ export function RegularElement(node, context) {
 
 	/** If true, needs `__value` for inputs */
 	const needs_special_value_handling =
-		name === 'option' || name === 'select' || bindings.has('group') || bindings.has('checked');
+		!context.state.analysis.custom_renderer &&
+		(name === 'option' || name === 'select' || bindings.has('group') || bindings.has('checked'));
 
 	if (has_spread) {
 		build_attribute_effect(

packages/svelte/tests/custom-renderers/samples/select-option/_config.js

@@ -0,0 +1,29 @@
+import { test } from '../../test';
+
+export default test({
+	html: '<select value="b"><option value="a">A</option><option value="b">B</option><option value="c">C</option></select> <p>b</p>',
+	test({ assert, target, serialize }) {
+		const select = target.children.find(
+			(/** @type {any} */ n) => n.type === 'element' && n.name === 'select'
+		);
+		assert.ok(select);
+
+		// The select element should have a value attribute set via the normal attribute path
+		assert.equal(select.attributes['value'], 'b');
+
+		// Each option should have its value as a regular attribute
+		const options = select.children.filter(
+			(/** @type {any} */ n) => n.type === 'element' && n.name === 'option'
+		);
+		assert.equal(options.length, 3);
+		assert.equal(options[0].attributes['value'], 'a');
+		assert.equal(options[1].attributes['value'], 'b');
+		assert.equal(options[2].attributes['value'], 'c');
+
+		const html = serialize(target);
+		assert.equal(
+			html,
+			'<select value="b"><option value="a">A</option><option value="b">B</option><option value="c">C</option></select> <p>b</p>'
+		);
+	}
+});

packages/svelte/tests/custom-renderers/samples/select-option/main.svelte

@@ -0,0 +1,10 @@
+<script>
+	let selected = $state('b');
+</script>
+
+<select value={selected}>
+	<option value="a">A</option>
+	<option value="b">B</option>
+	<option value="c">C</option>
+</select>
+<p>{selected}</p>