fix(merge): preserve original "rootDir" by default (#27963)

Fixes https://github.com/microsoft/playwright/issues/27877

docs/src/test-sharding-js.md

@@ -141,6 +141,8 @@ You can now see the reports have been merged and a combined HTML report is avail
 
 `npx playwright merge-reports path/to/blob-reports-dir` reads all blob reports from the passed directory and merges them into a single report.
 
+When merging reports from different OS'es you'll have to provide an explicit merge config to disambiguate which directory should be used as tests root.
+
 Supported options:
 - `--reporter reporter-to-use`
 
@@ -166,6 +168,7 @@ Supported options:
 
   ```ts title="merge.config.ts"
   export default {
+    testDir: 'e2e',
     reporter: [['html', { open: 'never' }]],
   };
   ```

packages/playwright/src/cli.ts

@@ -199,7 +199,8 @@ async function mergeReports(reportDir: string | undefined, opts: { [key: string]
     reporterDescriptions = config.config.reporter;
   if (!reporterDescriptions)
     reporterDescriptions = [[defaultReporter]];
-  await createMergedReport(config, dir, reporterDescriptions!);
+  const rootDirOverride = configFile ? config.config.rootDir : undefined;
+  await createMergedReport(config, dir, reporterDescriptions!, rootDirOverride);
 }
 
 function overridesFromOptions(options: { [key: string]: any }): ConfigCLIOverrides {

packages/playwright/src/isomorphic/teleReceiver.ts

@@ -196,7 +196,7 @@ export class TeleReporterReceiver {
   }
 
   private _onConfigure(config: JsonConfig) {
-    this._rootDir = this._reportConfig?.rootDir || config.rootDir;
+    this._rootDir = config.rootDir;
     this._listOnly = config.listOnly;
     this._config = this._parseConfig(config);
     this._reporter.onConfigure?.(this._config);
@@ -324,7 +324,6 @@ export class TeleReporterReceiver {
     const result = { ...baseFullConfig, ...config };
     if (this._reportConfig) {
       result.configFile = this._reportConfig.configFile;
-      result.rootDir = this._reportConfig.rootDir;
       result.reportSlowTests = this._reportConfig.reportSlowTests;
       result.quiet = this._reportConfig.quiet;
       result.reporter = [...this._reportConfig.reporter];

packages/playwright/src/reporters/merge.ts

@@ -34,7 +34,7 @@ type ReportData = {
   reportFile: string;
 };
 
-export async function createMergedReport(config: FullConfigInternal, dir: string, reporterDescriptions: ReporterDescription[]) {
+export async function createMergedReport(config: FullConfigInternal, dir: string, reporterDescriptions: ReporterDescription[], rootDirOverride: string | undefined) {
   const reporters = await createReporters(config, 'merge', reporterDescriptions);
   const multiplexer = new Multiplexer(reporters);
   const receiver = new TeleReporterReceiver(path.sep, multiplexer, false, config.config);
@@ -49,7 +49,7 @@ export async function createMergedReport(config: FullConfigInternal, dir: string
   const shardFiles = await sortedShardFiles(dir);
   if (shardFiles.length === 0)
     throw new Error(`No report files found in ${dir}`);
-  const eventData = await mergeEvents(dir, shardFiles, stringPool, printStatus);
+  const eventData = await mergeEvents(dir, shardFiles, stringPool, printStatus, rootDirOverride);
   printStatus(`processing test events`);
 
   const dispatchEvents = async (events: JsonEvent[]) => {
@@ -148,7 +148,7 @@ function findMetadata(events: JsonEvent[], file: string): BlobReportMetadata {
   return metadata;
 }
 
-async function mergeEvents(dir: string, shardReportFiles: string[], stringPool: StringInternPool, printStatus: StatusCallback) {
+async function mergeEvents(dir: string, shardReportFiles: string[], stringPool: StringInternPool, printStatus: StatusCallback, rootDirOverride: string | undefined) {
   const internalizer = new JsonStringInternalizer(stringPool);
 
   const configureEvents: JsonEvent[] = [];
@@ -207,7 +207,7 @@ async function mergeEvents(dir: string, shardReportFiles: string[], stringPool:
 
   return {
     prologue: [
-      mergeConfigureEvents(configureEvents),
+      mergeConfigureEvents(configureEvents, rootDirOverride),
       ...projectEvents,
       { method: 'onBegin', params: undefined },
     ],
@@ -219,7 +219,7 @@ async function mergeEvents(dir: string, shardReportFiles: string[], stringPool:
   };
 }
 
-function mergeConfigureEvents(configureEvents: JsonEvent[]): JsonEvent {
+function mergeConfigureEvents(configureEvents: JsonEvent[], rootDirOverride: string | undefined): JsonEvent {
   if (!configureEvents.length)
     throw new Error('No configure events found');
   let config: JsonConfig = {
@@ -235,6 +235,28 @@ function mergeConfigureEvents(configureEvents: JsonEvent[]): JsonEvent {
   };
   for (const event of configureEvents)
     config = mergeConfigs(config, event.params.config);
+
+  if (rootDirOverride) {
+    config.rootDir = rootDirOverride;
+  } else {
+    const rootDirs = new Set(configureEvents.map(e => e.params.config.rootDir));
+    if (rootDirs.size > 1) {
+      throw new Error([
+        `Blob reports being merged were recorded with different test directories, and`,
+        `merging cannot proceed. This may happen if you are merging reports from`,
+        `machines with different environments, like different operating systems or`,
+        `if the tests ran with different playwright configs.`,
+        ``,
+        `You can force merge by specifying a merge config file with "-c" option. If`,
+        `you'd like all test paths to be correct, make sure 'testDir' in the merge config`,
+        `file points to the actual tests location.`,
+        ``,
+        `Found directories:`,
+        ...rootDirs
+      ].join('\n'));
+    }
+  }
+
   return {
     method: 'onConfigure',
     params: {

tests/playwright-test/reporter-blob.spec.ts

@@ -639,7 +639,7 @@ test('generate html with attachment urls', async ({ runInlineTest, mergeReports,
 
   const htmlReportDir = test.info().outputPath('playwright-report');
   for (const entry of await fs.promises.readdir(htmlReportDir))
-    await (fs.promises as any).cp(path.join(htmlReportDir, entry), path.join(reportDir, entry), { recursive: true });
+    await fs.promises.cp(path.join(htmlReportDir, entry), path.join(reportDir, entry), { recursive: true });
 
   const oldSeveFile = server.serveFile;
   server.serveFile = async (req, res) => {
@@ -1416,3 +1416,99 @@ test('reporter list in the custom config', async ({ runInlineTest, mergeReports
   expect(text).toContain('testReporter.js');
   expect(text).toContain('{ myOpt: 1 }');
 });
+
+test('merge reports with different rootDirs', async ({ runInlineTest, mergeReports }) => {
+  test.info().annotations.push({ type: 'issue', description: 'https://github.com/microsoft/playwright/issues/27877' });
+  const files1 = {
+    'echo-reporter.js': `
+      export default class EchoReporter {
+        onBegin(config, suite) {
+          console.log('rootDir:', config.rootDir);
+        }
+        onTestBegin(test) {
+          console.log('test:', test.location.file);
+        }
+      };
+    `,
+    'merge.config.ts': `module.exports = {
+      testDir: 'mergeRoot',
+      reporter: './echo-reporter.js'
+     };`,
+    'dir1/playwright.config.ts': `module.exports = {
+      testDir: 'tests1',
+      reporter: [['blob', { outputDir: 'blob-report' }]]
+    };`,
+    'dir1/tests1/a.test.js': `
+      import { test, expect } from '@playwright/test';
+      test('math 1', async ({}) => { });
+    `,
+  };
+  await runInlineTest(files1, { workers: 1 }, undefined, { additionalArgs: ['--config', test.info().outputPath('dir1/playwright.config.ts')] });
+
+  const files2 = {
+    'dir2/playwright.config.ts': `module.exports = {
+      reporter: [['blob', { outputDir: 'blob-report' }]]
+    };`,
+    'dir2/tests2/b.test.js': `
+      import { test, expect } from '@playwright/test';
+      test('math 2', async ({}) => { });
+    `,
+  };
+  await runInlineTest(files2, { workers: 1 }, undefined, { additionalArgs: ['--config', test.info().outputPath('dir2/playwright.config.ts')] });
+
+  const allReportsDir = test.info().outputPath('all-blob-reports');
+  await fs.promises.cp(test.info().outputPath('dir1', 'blob-report', 'report.zip'), path.join(allReportsDir, 'report-1.zip'));
+  await fs.promises.cp(test.info().outputPath('dir2', 'blob-report', 'report.zip'), path.join(allReportsDir, 'report-2.zip'));
+
+  {
+    const { exitCode, output } = await mergeReports(allReportsDir);
+    expect(exitCode).toBe(1);
+    expect(output).toContain(`Blob reports being merged were recorded with different test directories`);
+  }
+
+  {
+    const { exitCode, output } = await mergeReports(allReportsDir, undefined, { additionalArgs: ['--config', 'merge.config.ts'] });
+    expect(exitCode).toBe(0);
+    expect(output).toContain(`rootDir: ${test.info().outputPath('mergeRoot')}`);
+    expect(output).toContain(`test: ${test.info().outputPath('mergeRoot', 'a.test.js')}`);
+    expect(output).toContain(`test: ${test.info().outputPath('mergeRoot', 'tests2', 'b.test.js')}`);
+  }
+});
+
+test('merge reports same rootDirs', async ({ runInlineTest, mergeReports }) => {
+  test.info().annotations.push({ type: 'issue', description: 'https://github.com/microsoft/playwright/issues/27877' });
+  const files = {
+    'echo-reporter.js': `
+      export default class EchoReporter {
+        onBegin(config, suite) {
+          console.log('rootDir:', config.rootDir);
+        }
+        onTestBegin(test) {
+          console.log('test:', test.location.file);
+        }
+      };
+    `,
+    'playwright.config.ts': `module.exports = {
+      testDir: 'tests',
+      reporter: [['blob', { outputDir: 'blob-report' }]]
+    };`,
+    'tests/dir1/a.test.js': `
+      import { test, expect } from '@playwright/test';
+      test('math 1', async ({}) => { });
+    `,
+    'tests/dir2/b.test.js': `
+      import { test, expect } from '@playwright/test';
+      test('math 2', async ({}) => { });
+    `,
+  };
+  await runInlineTest(files, { shard: `1/2` });
+  await runInlineTest(files, { shard: `2/2` }, { PWTEST_BLOB_DO_NOT_REMOVE: '1' });
+
+  const allReportsDir = test.info().outputPath('blob-report');
+
+  const { exitCode, output } = await mergeReports(allReportsDir, undefined, { additionalArgs: ['--reporter', './echo-reporter.js'] });
+  expect(exitCode).toBe(0);
+  expect(output).toContain(`rootDir: ${test.info().outputPath('tests')}`);
+  expect(output).toContain(`test: ${test.info().outputPath('tests', 'dir1', 'a.test.js')}`);
+  expect(output).toContain(`test: ${test.info().outputPath('tests', 'dir2', 'b.test.js')}`);
+});