From a2c96494e0f6cd1b20dc1d0e591ac6581e200c60 Mon Sep 17 00:00:00 2001
From: Max Schmitt <max@schmitt.mx>
Date: Tue, 14 Mar 2023 17:35:52 +0100
Subject: [PATCH] chore: throw pretty error if rest parameters is used inside
 fixtures (#21659)

Fixes https://github.com/microsoft/playwright/issues/21566
---
 .../playwright-test/src/common/fixtures.ts    |  5 +++++
 tests/playwright-test/fixtures.spec.ts        | 20 +++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/packages/playwright-test/src/common/fixtures.ts b/packages/playwright-test/src/common/fixtures.ts
index 2b8b5e55d3..716b224d9a 100644
--- a/packages/playwright-test/src/common/fixtures.ts
+++ b/packages/playwright-test/src/common/fixtures.ts
@@ -243,6 +243,11 @@ function innerFixtureParameterNames(fn: Function, location: Location, onError: L
     const colon = prop.indexOf(':');
     return colon === -1 ? prop.trim() : prop.substring(0, colon).trim();
   });
+  const restProperty = props.find(prop => prop.startsWith('...'));
+  if (restProperty) {
+    onError({ message: `Rest property "${restProperty}" is not supported. List all used fixtures explicitly, separated by comma.`, location });
+    return [];
+  }
   return props;
 }
 
diff --git a/tests/playwright-test/fixtures.spec.ts b/tests/playwright-test/fixtures.spec.ts
index e9c9fa0fb5..4edc66c3c1 100644
--- a/tests/playwright-test/fixtures.spec.ts
+++ b/tests/playwright-test/fixtures.spec.ts
@@ -58,6 +58,26 @@ test('should work with comments inside fixtures', async ({ runInlineTest }) => {
   expect(results[0].status).toBe('passed');
 });
 
+test('should throw a pretty error if fixtures use rest property', async ({ runInlineTest }) => {
+  const result = await runInlineTest({
+    'a.test.ts': `
+      import { test as base, expect } from '@playwright/test';
+      const test = base.extend({
+        asdf: async ({...props}, use) => await use(123),
+      });
+      test('should not allow rest property inside tests', ({...all}) => {
+        expect(asdf).toBe(123);
+      });
+      test('should not allow rest property inside fixtures', ({asdf}) => {
+        expect(asdf).toBe(123);
+      });
+      `
+  });
+  expect(result.exitCode).toBe(1);
+  expect(result.output).toContain('Rest property "...all" is not supported. List all used fixtures explicitly, separated by comma.');
+  expect(result.output).toContain('Rest property "...props" is not supported. List all used fixtures explicitly, separated by comma.');
+});
+
 test('should work with a sync test function', async ({ runInlineTest }) => {
   const { results } = await runInlineTest({
     'a.test.ts': `