From ce037b8500cd762497114bf8e130fa40de85a86f Mon Sep 17 00:00:00 2001
From: Bastien Caudan <bastien.caudan@gmail.com>
Date: Thu, 6 Feb 2020 14:37:50 +0100
Subject: [PATCH] :bug:[RUMF-293][fetch] handle fetch response text error
 (#252)

When consuming a fetch response body, it can be disturbed or locked, a rejected promise is then returned (cf https://fetch.spec.whatwg.org/#concept-body-consume-body).
This rejected promise was displayed on the browser console and the corresponding request was not collected.

Handle the rejected promise and add the corresponding error to the collected request response.
---
 packages/core/src/requestCollection.ts       |  7 ++++++-
 packages/core/src/specHelper.ts              | 10 +++++++++-
 packages/core/test/requestCollection.spec.ts | 17 +++++++++++++++++
 3 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/packages/core/src/requestCollection.ts b/packages/core/src/requestCollection.ts
index 4c3f051f10..e521eb9462 100644
--- a/packages/core/src/requestCollection.ts
+++ b/packages/core/src/requestCollection.ts
@@ -103,7 +103,12 @@ export function trackFetch(observable: RequestObservable) {
           type: RequestType.FETCH,
         })
       } else if ('status' in response) {
-        const text = await response.clone().text()
+        let text: string
+        try {
+          text = await response.clone().text()
+        } catch (e) {
+          text = `Unable to retrieve response: ${e}`
+        }
         observable.notify({
           duration,
           method,
diff --git a/packages/core/src/specHelper.ts b/packages/core/src/specHelper.ts
index c8990e40f8..b4ac67b076 100644
--- a/packages/core/src/specHelper.ts
+++ b/packages/core/src/specHelper.ts
@@ -55,7 +55,14 @@ export class FetchStubBuilder {
         resolve({
           ...response,
           clone: () => {
-            const cloned = { text: async () => response.responseText }
+            const cloned = {
+              text: async () => {
+                if (response.responseTextError) {
+                  throw response.responseTextError
+                }
+                return response.responseText
+              },
+            }
             return cloned as Response
           },
         }) as Promise<ResponseStub>
@@ -67,6 +74,7 @@ export class FetchStubBuilder {
 
 export interface ResponseStub extends Partial<Response> {
   responseText?: string
+  responseTextError?: Error
 }
 
 export type FetchStub = (input: RequestInfo, init?: RequestInit) => FetchStubPromise
diff --git a/packages/core/test/requestCollection.spec.ts b/packages/core/test/requestCollection.spec.ts
index df3c27b262..d7ab1c81a1 100644
--- a/packages/core/test/requestCollection.spec.ts
+++ b/packages/core/test/requestCollection.spec.ts
@@ -70,6 +70,23 @@ describe('fetch tracker', () => {
     })
   })
 
+  // https://fetch.spec.whatwg.org/#concept-body-consume-body
+  it('should track fetch with response text error', (done) => {
+    fetchStub(FAKE_URL).resolveWith({ status: 200, responseTextError: new Error('locked') })
+
+    fetchStubBuilder.whenAllComplete((requests: RequestDetails[]) => {
+      const request = requests[0]
+      expect(request.type).toEqual(RequestType.FETCH)
+      expect(request.method).toEqual('GET')
+      expect(request.url).toEqual(FAKE_URL)
+      expect(request.status).toEqual(200)
+      expect(request.response).toMatch(/Error: locked/)
+      expect(isRejected(request)).toBe(false)
+      expect(isServerError(request)).toBe(false)
+      done()
+    })
+  })
+
   it('should track opaque fetch', (done) => {
     // https://fetch.spec.whatwg.org/#concept-filtered-response-opaque
     fetchStub(FAKE_URL).resolveWith({ status: 0, type: 'opaque' })