fix(routeFromHAR): hack harRouter to merge set-cookie headers

packages/playwright-core/src/client/harRouter.ts

@@ -68,9 +68,16 @@ export class HarRouter {
       // test when HAR was recorded but we'd abort it immediately.
       if (response.status === -1)
         return;
+
+      // route.fulfill does not support multiple set-cookie headers. We need to merge them into one.
+      const setCookieHeaders = response.headers!.filter(h => h.name.toLowerCase() === 'set-cookie');
+      const transformedHeaders = response.headers!.filter(h => h.name.toLowerCase() !== 'set-cookie');
+      if (setCookieHeaders.length > 1)
+        transformedHeaders.push({ name: 'set-cookie', value: setCookieHeaders.map(h => h.value).join('\n') });
+
       await route.fulfill({
         status: response.status,
-        headers: Object.fromEntries(response.headers!.map(h => [h.name, h.value])),
+        headers: Object.fromEntries(transformedHeaders.map(h => [h.name, h.value])),
         body: response.body!
       });
       return;

tests/assets/har-fulfill.har

@@ -62,6 +62,14 @@
             {
               "name": "content-type",
               "value": "text/html"
+            },
+            {
+              "name": "Set-Cookie",
+              "value": "playwright=works;"
+            },
+            {
+              "name": "Set-Cookie",
+              "value": "with=multiple-set-cookie-headers;"
             }
           ],
           "content": {

tests/library/browsercontext-har.spec.ts

@@ -358,6 +358,14 @@ it('should record overridden requests to har', async ({ contextFactory, server }
   expect(await page2.evaluate(fetchFunction, { path: '/echo', body: '12' })).toBe('12');
 });
 
+it('should replay requests with multiple set-cookie headers properly', async ({ context, asset }) => {
+  const path = asset('har-fulfill.har');
+  await context.routeFromHAR(path);
+  const page = await context.newPage();
+  await page.goto('http://no.playwright/');
+  expect(await page.context().cookies()).toEqual([expect.objectContaining({ name: 'playwright', value: 'works' }), expect.objectContaining({ name: 'with', value: 'multiple-set-cookie-headers' })]);
+});
+
 it('should disambiguate by header', async ({ contextFactory, server }, testInfo) => {
   server.setRoute('/echo', async (req, res) => {
     res.end(req.headers['baz']);