fix: rebuild project tree from scratch when listing tests (#30407)

Instead of filtering tests assuming there are no two projects with same
name we always rebuild test tree from scratch and restore previos test
results in the list mode.

Fixes #30396

packages/playwright/src/isomorphic/teleReceiver.ts

@@ -146,6 +146,11 @@ export class TeleReporterReceiver {
     this._reporter = reporter;
   }
 
+  reset() {
+    this._rootSuite._entries = [];
+    this._tests.clear();
+  }
+
   dispatch(message: JsonEvent): Promise<void> | void {
     const { method, params } = message;
     if (method === 'onConfigure') {
@@ -206,35 +211,6 @@ export class TeleReporterReceiver {
     projectSuite._project = this._parseProject(project);
     for (const suite of project.suites)
       this._mergeSuiteInto(suite, projectSuite);
-
-    // Remove deleted tests when listing. Empty suites will be auto-filtered
-    // in the UI layer.
-    if (this.isListing) {
-      const testIds = new Set<string>();
-      const collectIds = (suite: JsonSuite) => {
-        suite.entries.forEach(entry => {
-          if ('testId' in entry)
-            testIds.add(entry.testId);
-          else
-            collectIds(entry);
-        });
-      };
-      project.suites.forEach(collectIds);
-
-      const filterTests = (suite: TeleSuite) => {
-        suite._entries = suite._entries.filter(entry => {
-          if (entry.type === 'test') {
-            if (testIds.has(entry.id))
-              return true;
-            this._tests.delete(entry.id);
-            return false;
-          }
-          filterTests(entry);
-          return true;
-        });
-      };
-      filterTests(projectSuite);
-    }
   }
 
   private _onBegin() {
@@ -545,6 +521,11 @@ export class TeleTestCase implements reporterTypes.TestCase {
     this._resultsMap.clear();
   }
 
+  _restoreResults(snapshot: Map<string, TeleTestResult>) {
+    this.results = [...snapshot.values()];
+    this._resultsMap = snapshot;
+  }
+
   _createTestResult(id: string): TeleTestResult {
     const result = new TeleTestResult(this.results.length);
     this.results.push(result);
@@ -585,7 +566,7 @@ class TeleTestStep implements reporterTypes.TestStep {
   }
 }
 
-class TeleTestResult implements reporterTypes.TestResult {
+export class TeleTestResult implements reporterTypes.TestResult {
   retry: reporterTypes.TestResult['retry'];
   parallelIndex: reporterTypes.TestResult['parallelIndex'] = -1;
   workerIndex: reporterTypes.TestResult['workerIndex'] = -1;

packages/trace-viewer/src/ui/teleSuiteUpdater.ts

@@ -15,6 +15,7 @@
  */
 
 import { TeleReporterReceiver, TeleSuite } from '@testIsomorphic/teleReceiver';
+import type { TeleTestCase, TeleTestResult } from '@testIsomorphic/teleReceiver';
 import { statusEx } from '@testIsomorphic/testTree';
 import type { ReporterV2 } from 'playwright/src/reporters/reporterV2';
 import type * as reporterTypes from 'playwright/types/testReporter';
@@ -27,7 +28,7 @@ export type TeleSuiteUpdaterOptions = {
 };
 
 export class TeleSuiteUpdater {
-  rootSuite: reporterTypes.Suite | undefined;
+  rootSuite: TeleSuite | undefined;
   config: reporterTypes.FullConfig | undefined;
   readonly loadErrors: reporterTypes.TestError[] = [];
   readonly progress: Progress = {
@@ -41,6 +42,7 @@ export class TeleSuiteUpdater {
   private _lastRunReceiver: TeleReporterReceiver | undefined;
   private _lastRunTestCount = 0;
   private _options: TeleSuiteUpdaterOptions;
+  private _testResultsSnapshot: Map<string,  Map<string, TeleTestResult>> | undefined;
 
   constructor(options: TeleSuiteUpdaterOptions) {
     this._receiver = new TeleReporterReceiver(this._createReporter(), {
@@ -76,7 +78,16 @@ export class TeleSuiteUpdater {
 
       onBegin: (suite: reporterTypes.Suite) => {
         if (!this.rootSuite)
-          this.rootSuite = suite;
+          this.rootSuite = suite as TeleSuite;
+        // As soon as new test tree is built add previous results.
+        if (this._testResultsSnapshot) {
+          (this.rootSuite.allTests() as TeleTestCase[]).forEach(test => {
+            const results = this._testResultsSnapshot!.get(test.id);
+            if (results)
+              test._restoreResults(results);
+          });
+          this._testResultsSnapshot = undefined;
+        }
         this.progress.total = this._lastRunTestCount;
         this.progress.passed = 0;
         this.progress.failed = 0;
@@ -123,10 +134,13 @@ export class TeleSuiteUpdater {
   }
 
   processListReport(report: any[]) {
-    this._receiver.isListing = true;
+    // Save test results and reset all projects, the results will be restored after
+    // new project structure is built.
+    if (this.rootSuite)
+      this._testResultsSnapshot = new Map((this.rootSuite.allTests() as TeleTestCase[]).map(test => [test.id, test._resultsMap]));
+    this._receiver.reset();
     for (const message of report)
       this._receiver.dispatch(message);
-    this._receiver.isListing = false;
   }
 
   processTestReportEvent(message: any) {

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

@@ -48,6 +48,60 @@ test('should list tests', async ({ runUITest }) => {
   `);
 });
 
+test('should list all tests from projects with clashing names', async ({ runUITest }) => {
+  test.info().annotations.push({ type: 'issue', description: 'https://github.com/microsoft/playwright/issues/30396' });
+  const { page } = await runUITest({
+    'playwright.config.ts': `
+      import { defineConfig } from '@playwright/test';
+
+      export default defineConfig({
+        projects: [
+          {
+            name: 'proj-uno',
+            testDir: './foo',
+          },
+          {
+            name: 'proj-dos',
+            testDir: './foo',
+          },
+          {
+            name: 'proj-uno',
+            testDir: './bar',
+          },
+          {
+            name: 'proj-dos',
+            testDir: './bar',
+          },
+        ]
+      });
+    `,
+    'foo/a.test.ts': `
+      import { test, expect } from '@playwright/test';
+      test('one', () => {});
+      test('two', () => {});
+    `,
+    'bar/b.test.ts': `
+      import { test, expect } from '@playwright/test';
+      test('three', () => {});
+      test('four', () => {});
+    `,
+  });
+  await page.getByTestId('test-tree').getByText('b.test.ts').click();
+  await page.keyboard.press('ArrowRight');
+  await page.getByTestId('test-tree').getByText('a.test.ts').click();
+  await page.keyboard.press('ArrowRight');
+  await expect.poll(dumpTestTree(page)).toBe(`
+    ▼ ◯ bar
+      ▼ ◯ b.test.ts
+          ◯ three
+          ◯ four
+    ▼ ◯ foo
+      ▼ ◯ a.test.ts <=
+          ◯ one
+          ◯ two
+  `);
+});
+
 test('should traverse up/down', async ({ runUITest }) => {
   const { page } = await runUITest(basicTestTree);
   await page.getByText('a.test.ts').click();