fix(yaml): escape to disambiguate yaml arrays (#34096)

packages/playwright-core/src/server/injected/yaml.ts

@@ -82,6 +82,10 @@ function yamlStringNeedsQuotes(str: string): boolean {
   if (/[{}`]/.test(str))
     return true;
 
+  // YAML array starts with [
+  if (/^\[/.test(str))
+    return true;
+
   // Non-string types recognized by YAML
   if (!isNaN(Number(str)) || ['y', 'n', 'yes', 'no', 'true', 'false', 'on', 'off', 'null'].includes(str.toLowerCase()))
     return true;

tests/page/page-aria-snapshot.spec.ts

@@ -482,6 +482,7 @@ it('should escape yaml text in text nodes', async ({ page }) => {
       {<a href="#">four</a>}
       [<a href="#">five</a>]
     </ul>
+    <div>[Select all]</div>
   `);
 
   await checkAndMatchSnapshot(page.locator('body'), `
@@ -504,6 +505,7 @@ it('should escape yaml text in text nodes', async ({ page }) => {
       - text: "} ["
       - link "five"
       - text: "]"
+    - text: "[Select all]"
   `);
 });