Merge pull request #2164 from hypothesis/sentry-fetch-errors

Make fetch exceptions consistent and filter them from Sentry

src/sidebar/services/api.js

@@ -136,6 +136,12 @@ function createAPICall(
           body: data ? JSON.stringify(stripInternalProperties(data)) : null,
           headers,
           method: descriptor.method,
+        }).catch(() => {
+          // Re-throw Fetch errors such that they all "look the same" (different
+          // browsers throw different Errors on Fetch failure). This allows
+          // Fetch failures to be either handled in particular ways higher up
+          // or for them to be ignored in error reporting (see `sentry` config).
+          throw new Error(`Fetch operation failed for URL '${url}'`);
         });
       })
       .then(response => {

src/sidebar/services/test/api-test.js

@@ -175,7 +175,8 @@ describe('sidebar.services.api', function () {
         // Network error
         status: null,
         body: 'Service unreachable.',
-        expectedMessage: 'Service unreachable.',
+        expectedMessage:
+          "Fetch operation failed for URL 'https://example.com/api/profile'",
       },
       {
         // Request failed with an error given in the JSON body

src/sidebar/util/sentry.js

@@ -51,6 +51,8 @@ export function init(config) {
   Sentry.init({
     dsn: config.dsn,
     environment: config.environment,
+    // Do not log Fetch failures to avoid inundating with unhandled fetch exceptions
+    ignoreErrors: ['Fetch operation failed'],
     release: '__VERSION__', // replaced by versionify
     whitelistUrls,
 

src/sidebar/util/test/sentry-test.js

@@ -75,6 +75,20 @@ describe('sidebar/util/sentry', () => {
       );
     });
 
+    it('configures Sentry to ignore Errors with matching the text "Fetch operation failed"', () => {
+      sentry.init({
+        dsn: 'test-dsn',
+        environment: 'dev',
+      });
+
+      assert.calledWith(
+        fakeSentry.init,
+        sinon.match({
+          ignoreErrors: ['Fetch operation failed'],
+        })
+      );
+    });
+
     it('disables the URL whitelist if `document.currentScript` is inaccessible', () => {
       fakeDocumentCurrentScript.get(() => null);