fix(Network): explicitly throw on content request for redirect response (#2352)

DevTools protocol doesn't support returning body of redirect responses.
We should explicitly throw in this case.

References #1896.

lib/NetworkManager.js

@@ -191,6 +191,7 @@ class NetworkManager extends EventEmitter {
     const response = new Response(this._client, request, redirectStatus, redirectHeaders, fromDiskCache, fromServiceWorker, securityDetails);
     request._response = response;
     request._redirectChain.push(request);
+    response._bodyLoadedPromiseFulfill.call(null, new Error('Response body is unavailable for redirect responses'));
     this._requestIdToRequest.delete(request._requestId);
     this._interceptionIdToRequest.delete(request._interceptionId);
     this._attemptedAuthentications.delete(request._interceptionId);
@@ -274,7 +275,7 @@ class NetworkManager extends EventEmitter {
     // @see https://crbug.com/750469
     if (!request)
       return;
-    request._completePromiseFulfill.call(null);
+    request.response()._bodyLoadedPromiseFulfill.call(null);
     this._requestIdToRequest.delete(request._requestId);
     this._interceptionIdToRequest.delete(request._interceptionId);
     this._attemptedAuthentications.delete(request._interceptionId);
@@ -291,7 +292,9 @@ class NetworkManager extends EventEmitter {
     if (!request)
       return;
     request._failureText = event.errorText;
-    request._completePromiseFulfill.call(null);
+    const response = request.response();
+    if (response)
+      response._bodyLoadedPromiseFulfill.call(null);
     this._requestIdToRequest.delete(request._requestId);
     this._interceptionIdToRequest.delete(request._interceptionId);
     this._attemptedAuthentications.delete(request._interceptionId);
@@ -319,9 +322,6 @@ class Request {
     this._interceptionHandled = false;
     this._response = null;
     this._failureText = null;
-    this._completePromise = new Promise(fulfill => {
-      this._completePromiseFulfill = fulfill;
-    });
 
     this._url = url;
     this._resourceType = resourceType.toLowerCase();
@@ -523,6 +523,10 @@ class Response {
     this._request = request;
     this._contentPromise = null;
 
+    this._bodyLoadedPromise = new Promise(fulfill => {
+      this._bodyLoadedPromiseFulfill = fulfill;
+    });
+
     this._status = status;
     this._url = request.url();
     this._fromDiskCache = fromDiskCache;
@@ -581,7 +585,9 @@ class Response {
    */
   buffer() {
     if (!this._contentPromise) {
-      this._contentPromise = this._request._completePromise.then(async() => {
+      this._contentPromise = this._bodyLoadedPromise.then(async error => {
+        if (error)
+          throw error;
         const response = await this._client.send('Network.getResponseBody', {
           requestId: this._request._requestId
         });

test/network.spec.js

@@ -94,6 +94,17 @@ module.exports.addTests = function({testRunner, expect}) {
       expect(await response.text()).toBe('{"foo": "bar"}\n');
       expect(await response.json()).toEqual({foo: 'bar'});
     });
+    it('Page.Events.Response should throw when requesting body of redirected response', async({page, server}) => {
+      server.setRedirect('/foo.html', '/empty.html');
+      const response = await page.goto(server.PREFIX + '/foo.html');
+      const redirectChain = response.request().redirectChain();
+      expect(redirectChain.length).toBe(1);
+      const redirected = redirectChain[0].response();
+      expect(redirected.status()).toBe(302);
+      let error = null;
+      await redirected.text().catch(e => error = e);
+      expect(error.message).toContain('Response body is unavailable for redirect responses');
+    });
     it('Page.Events.Response should not report body unless request is finished', async({page, server}) => {
       await page.goto(server.EMPTY_PAGE);
       // Setup server to trap request.