cherry-pick(#22126): fix(tracing): avoid clashing network file names

With two contexts in the same test, we can get:
- `<testId>.network` and `<testId>-1.network` files;
- for export, we can copy `<testId>.network` into `<testId>-1.network`
and try to copy into a file when another trace is reading from it.

Fixes #22089.

packages/playwright-core/src/server/trace/recorder/tracing.ts

@@ -261,8 +261,12 @@ export class Tracing extends SdkObject implements InstrumentationListener, Snaps
         return {};
 
       // Network file survives across chunks, make a snapshot before returning the resulting entries.
-      const suffix = state.chunkOrdinal ? `-${state.chunkOrdinal}` : ``;
-      const networkFile = path.join(state.tracesDir, state.traceName + `${suffix}.network`);
+      // We should pick a name starting with "traceName" and ending with .network.
+      // Something like <traceName>someSuffixHere.network.
+      // However, this name must not clash with any other "traceName".network in the same tracesDir.
+      // We can use <traceName>-<guid>.network, but "-pwnetcopy-0" suffix is more readable
+      // and makes it easier to debug future issues.
+      const networkFile = path.join(state.tracesDir, state.traceName + `-pwnetcopy-${state.chunkOrdinal}.network`);
       await fs.promises.copyFile(state.networkFile, networkFile);
 
       const entries: NameValue[] = [];

tests/playwright-test/playwright.trace.spec.ts

@@ -132,6 +132,42 @@ test('should not throw with trace: on-first-retry and two retries in the same wo
   expect(result.flaky).toBe(6);
 });
 
+test('should not mixup network files between contexts', async ({ runInlineTest, server }, testInfo) => {
+  // NOTE: this test reproduces the issue 10% of the time. Running with --repeat-each=20 helps.
+  test.info().annotations.push({ type: 'issue', description: 'https://github.com/microsoft/playwright/issues/22089' });
+
+  const result = await runInlineTest({
+    'playwright.config.ts': `
+      export default { use: { trace: 'on' } };
+    `,
+    'a.spec.ts': `
+      import { test, expect } from '@playwright/test';
+
+      let page1, page2;
+
+      test.beforeAll(async ({ browser }) => {
+        page1 = await browser.newPage();
+        await page1.goto("${server.EMPTY_PAGE}");
+
+        page2 = await browser.newPage();
+        await page2.goto("${server.EMPTY_PAGE}");
+      });
+
+      test.afterAll(async () => {
+        await page1.close();
+        await page2.close();
+      });
+
+      test('example', async ({ page }) => {
+        await page.goto("${server.EMPTY_PAGE}");
+      });
+    `,
+  }, { workers: 1, timeout: 15000 });
+  expect(result.exitCode).toEqual(0);
+  expect(result.passed).toBe(1);
+  expect(fs.existsSync(testInfo.outputPath('test-results', 'a-example', 'trace.zip'))).toBe(true);
+});
+
 test('should save sources when requested', async ({ runInlineTest }, testInfo) => {
   const result = await runInlineTest({
     'playwright.config.ts': `

tests/playwright-test/ui-mode-test-run.spec.ts

@@ -228,7 +228,7 @@ test('should stop', async ({ runUITest }) => {
     `,
   });
 
-  await expect(page.getByTitle('Run all')).toBeEnabled();
+  await expect(page.getByTitle('Run all')).toBeEnabled({ timeout: 15000 });
   await expect(page.getByTitle('Stop')).toBeDisabled();
 
   await page.getByTitle('Run all').click();