detect base ref from environment variables

packages/playwright/src/common/config.ts

@@ -49,7 +49,7 @@ export class FullConfigInternal {
   cliArgs: string[] = [];
   cliGrep: string | undefined;
   cliGrepInvert: string | undefined;
-  cliOnlyChanged: string | boolean | undefined;
+  cliOnlyChanged: string | undefined;
   cliProjectFilter?: string[];
   cliListOnly = false;
   cliPassWithNoTests?: boolean;

packages/playwright/src/program.ts

@@ -153,6 +153,13 @@ Examples:
   $ npx playwright merge-reports playwright-report`);
 }
 
+function getOnlyChangedArg(input: string | boolean | undefined): string | undefined {
+  if (typeof input === 'string')
+    return input;
+  if (input === true)
+    return process.env.GITHUB_BASE_REF ?? process.env['Build.PullRequest.TargetBranch'] ?? 'HEAD';
+}
+
 
 async function runTests(args: string[], opts: { [key: string]: any }) {
   await startProfiling();
@@ -192,7 +199,7 @@ async function runTests(args: string[], opts: { [key: string]: any }) {
 
   config.cliArgs = args;
   config.cliGrep = opts.grep as string | undefined;
-  config.cliOnlyChanged = opts.onlyChanged as string | boolean | undefined;
+  config.cliOnlyChanged = getOnlyChangedArg(opts.onlyChanged);
   config.cliGrepInvert = opts.grepInvert as string | undefined;
   config.cliListOnly = !!opts.list;
   config.cliProjectFilter = opts.project || undefined;

packages/playwright/src/util.ts

@@ -80,15 +80,14 @@ export type TestFileFilter = {
   column: number | null;
 };
 
-export async function detectChangedFiles(onlyChangedParam: string | true): Promise<string[]> {
-  const baseCommit = onlyChangedParam === true ? 'HEAD' : onlyChangedParam;
+export async function detectChangedFiles(baseCommit: string): Promise<string[]> {
   const untrackedFiles = childProcess.execSync('git ls-files --others --exclude-standard', { encoding: 'utf-8' }).split('\n').filter(Boolean);
   const changedFiles = childProcess.execSync(`git diff ${baseCommit} --name-only`, { encoding: 'utf-8' }).split('\n').filter(Boolean);
 
   return [...untrackedFiles, ...changedFiles];
 }
 
-export async function createFileFiltersFromArguments(args: string[], onlyChanged: string | boolean | undefined): Promise<TestFileFilter[]> {
+export async function createFileFiltersFromArguments(args: string[], onlyChanged: string | undefined): Promise<TestFileFilter[]> {
   if (onlyChanged)
     args = await detectChangedFiles(onlyChanged);
 

tests/playwright-test/only-changed.spec.ts

@@ -103,3 +103,68 @@ test('should diff based on base commit', async ({ runInlineTest }) => {
   expect(result.output).toContain('b.spec.ts');
 });
 
+test.describe('should be smart about PR base reference from CI', () => {
+  test('GitHub Actions', async ({ runInlineTest }) => {
+    const result = await runInlineTest({
+      'a.spec.ts': `
+          import { test, expect } from '@playwright/test';
+          test('fails', () => { expect(1).toBe(2); });
+        `,
+      'b.spec.ts': `
+          import { test, expect } from '@playwright/test';
+          test('fails', () => { expect(1).toBe(2); });
+        `,
+      async [magicFileCreationSymbol](baseDir) {
+        execSync(`git init --initial-branch=main`, { cwd: baseDir });
+        execSync(`git add .`, { cwd: baseDir });
+        execSync(`git commit -m init`, { cwd: baseDir });
+
+        await writeFile(join(baseDir, 'b.spec.ts'), `
+          import { test, expect } from '@playwright/test';
+          test('fails', () => { expect(1).toBe(3); });
+        `);
+
+        execSync(`git commit -a -m update`, { cwd: baseDir });
+      }
+    }, { 'only-changed': true }, { GITHUB_BASE_REF: 'HEAD~1' });
+
+    expect(result.exitCode).toBe(1);
+    expect(result.failed).toBe(1);
+    expect(result.output).toContain('b.spec.ts');
+  });
+
+
+  test('Azure DevOps', async ({ runInlineTest }) => {
+    const result = await runInlineTest({
+      'a.spec.ts': `
+          import { test, expect } from '@playwright/test';
+          test('fails', () => { expect(1).toBe(2); });
+        `,
+      'b.spec.ts': `
+          import { test, expect } from '@playwright/test';
+          test('fails', () => { expect(1).toBe(2); });
+        `,
+      async [magicFileCreationSymbol](baseDir) {
+        execSync(`git init --initial-branch=main`, { cwd: baseDir });
+        execSync(`git add .`, { cwd: baseDir });
+        execSync(`git commit -m init`, { cwd: baseDir });
+
+        await writeFile(join(baseDir, 'b.spec.ts'), `
+          import { test, expect } from '@playwright/test';
+          test('fails', () => { expect(1).toBe(3); });
+        `);
+
+        execSync(`git commit -a -m update`, { cwd: baseDir });
+      }
+    }, {
+      'only-changed': true
+    }, {
+      // see https://learn.microsoft.com/en-us/azure/devops/pipelines/release/variables?view=azure-devops&tabs=batch#primary-artifact
+      'Build.PullRequest.TargetBranch': 'HEAD~1'
+    });
+
+    expect(result.exitCode).toBe(1);
+    expect(result.failed).toBe(1);
+    expect(result.output).toContain('b.spec.ts');
+  });
+});