fix: falsey behavior in route.continue, page.post, testInfo.attach (#11421)

In several of the Playwright APIs, falsey values were not handled correctly. This changeset adds tests (and some fixes):

- route.continue: If options.postData was the empty string, the continue failed to override the post data.
- page.post (application/json with options.data: false|''|0|null): Raw falsey values were getting dropped (i.e. you can't do the equivalent of curl --header application/json … -d 'false'). This has been fixed with most values across all browsers, but an additional fix is needed for 'null' which the channel serializer treats extra specially.
- testInfo.attach: This didn't get reported as an error when options.path was the empty string, but should have been.
#11413 (and its fix #11414) inspired this search as they are the same
class of bug.

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

@@ -78,7 +78,7 @@ export class Request extends ChannelOwner<channels.RequestChannel> implements ap
     if (this._redirectedFrom)
       this._redirectedFrom._redirectedTo = this;
     this._provisionalHeaders = new RawHeaders(initializer.headers);
-    this._postData = initializer.postData ? Buffer.from(initializer.postData, 'base64') : null;
+    this._postData = initializer.postData !== undefined ? Buffer.from(initializer.postData, 'base64') : null;
     this._timing = {
       startTime: 0,
       domainLookupStart: -1,

packages/playwright-core/src/dispatchers/networkDispatchers.ts

@@ -123,7 +123,7 @@ export class RouteDispatcher extends Dispatcher<Route, channels.RouteChannel> im
       url: params.url,
       method: params.method,
       headers: params.headers,
-      postData: params.postData ? Buffer.from(params.postData, 'base64') : undefined,
+      postData: params.postData !== undefined ? Buffer.from(params.postData, 'base64') : undefined,
     });
   }
 

packages/playwright-core/src/server/fetch.ts

@@ -579,7 +579,7 @@ function isJsonParsable(value: any) {
 
 function serializePostData(params: channels.APIRequestContextFetchParams, headers: { [name: string]: string }): Buffer | undefined {
   assert((params.postData ? 1 : 0) + (params.jsonData ? 1 : 0) + (params.formData ? 1 : 0) + (params.multipartData ? 1 : 0) <= 1, `Only one of 'data', 'form' or 'multipart' can be specified`);
-  if (params.jsonData) {
+  if (params.jsonData !== undefined) {
     const json = isJsonParsable(params.jsonData) ? params.jsonData : JSON.stringify(params.jsonData);
     headers['content-type'] ??= 'application/json';
     return Buffer.from(json, 'utf8');
@@ -599,7 +599,7 @@ function serializePostData(params: channels.APIRequestContextFetchParams, header
     }
     headers['content-type'] ??= formData.contentTypeHeader();
     return formData.finish();
-  } else if (params.postData) {
+  } else if (params.postData !== undefined) {
     headers['content-type'] ??= 'application/octet-stream';
     return Buffer.from(params.postData, 'base64');
   }

packages/playwright-test/src/dispatcher.ts

@@ -204,7 +204,7 @@ export class Dispatcher {
         name: a.name,
         path: a.path,
         contentType: a.contentType,
-        body: typeof a.body !== 'undefined' ? Buffer.from(a.body, 'base64') : undefined
+        body: a.body !== undefined ? Buffer.from(a.body, 'base64') : undefined
       }));
       result.status = params.status;
       test.expectedStatus = params.expectedStatus;

packages/playwright-test/src/workerRunner.ts

@@ -267,7 +267,7 @@ export class WorkerRunner extends EventEmitter {
       attach: async (name: string, options: { path?: string, body?: string | Buffer, contentType?: string } = {}) => {
         if ((options.path !== undefined ? 1 : 0) + (options.body !== undefined ? 1 : 0) !== 1)
           throw new Error(`Exactly one of "path" and "body" must be specified`);
-        if (options.path) {
+        if (options.path !== undefined) {
           const hash = calculateSha1(options.path);
           const dest = testInfo.outputPath('attachments', hash + path.extname(options.path));
           await fs.promises.mkdir(path.dirname(dest), { recursive: true });

tests/browsercontext-route.spec.ts

@@ -212,3 +212,28 @@ it('should support the times parameter with route matching', async ({ context, p
   await page.goto(server.EMPTY_PAGE);
   expect(intercepted).toHaveLength(1);
 });
+
+it('should overwrite post body with empty string', async ({ context, server, page, browserName }) => {
+  await context.route('**/empty.html', route => {
+    route.continue({
+      postData: '',
+    });
+  });
+
+  const [req] = await Promise.all([
+    server.waitForRequest('/empty.html'),
+    page.setContent(`
+      <script>
+        (async () => {
+            await fetch('${server.EMPTY_PAGE}', {
+              method: 'POST',
+              body: 'original',
+            });
+        })()
+      </script>
+    `),
+  ]);
+
+  const body = (await req.postBody).toString();
+  expect(body).toBe('');
+});

tests/global-fetch.spec.ts

@@ -266,12 +266,17 @@ it('should remove content-length from reidrected post requests', async ({ playwr
 });
 
 
-const serialization = [
+const serialization: [string, any][] = [
   ['object', { 'foo': 'bar' }],
   ['array', ['foo', 'bar', 2021]],
   ['string', 'foo'],
+  ['string (falsey)', ''],
   ['bool', true],
+  ['bool (false)', false],
   ['number', 2021],
+  ['number (falsey)', 0],
+  ['null', null],
+  ['literal string undefined', 'undefined'],
 ];
 for (const [type, value] of serialization) {
   const stringifiedValue = JSON.stringify(value);

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

@@ -103,6 +103,19 @@ test(`testInfo.attach errors`, async ({ runInlineTest }) => {
   expect(result.exitCode).toBe(1);
 });
 
+test(`testInfo.attach errors with empty path`, async ({ runInlineTest }) => {
+  const result = await runInlineTest({
+    'a.test.js': `
+      const { test } = pwt;
+      test('fail', async ({}, testInfo) => {
+        await testInfo.attach('name', { path: '' });
+      });
+    `,
+  }, { reporter: 'line', workers: 1 });
+  expect(stripAscii(result.output)).toMatch(/Error: ENOENT: no such file or directory, copyfile ''/);
+  expect(result.exitCode).toBe(1);
+});
+
 test(`testInfo.attach error in fixture`, async ({ runInlineTest }) => {
   const result = await runInlineTest({
     'a.test.js': `