Makes sure SDK still works after loading bad bundles.

Author: wu-hui

packages/firestore/src/core/sync_engine.ts

@@ -449,9 +449,6 @@ export class SyncEngine implements RemoteSyncer {
 
     return (
       this.loadBundleAsync(bundleReader, task)
-        // TODO(wuandy): Loading a bundle will fail the entire SDK if there is
-        // an error. We really should have a way to run operations on async queue
-        // and not failing the rest if there is an error.
         .catch(reason => {
           task.failedWith(reason);
         })

packages/firestore/test/integration/api/bundle.test.ts

@@ -226,14 +226,31 @@ apiDescribe('Bundles', (persistence: boolean) => {
 
   it('load with documents from other projects fails.', () => {
     return withTestDb(persistence, async db => {
-      const builder = bundleWithTestDocs(db);
+      let builder = bundleWithTestDocs(db);
       return withAlternateTestDb(persistence, async otherDb => {
         // eslint-disable-next-line @typescript-eslint/no-floating-promises
         expect(
           otherDb.loadBundle(
             builder.build('test-bundle', { seconds: 1001, nanos: 9999 })
           )
         ).to.be.rejectedWith('Tried to deserialize key from different project');
+
+        // Verify otherDb still functions, despite loaded a problematic bundle.
+        builder = bundleWithTestDocs(otherDb);
+        const progress = await otherDb.loadBundle(
+          builder.build('test-bundle', { seconds: 1001, nanos: 9999 })
+        );
+        verifySuccessProgress(progress);
+
+        // Read from cache. These documents do not exist in backend, so they can
+        // only be read from cache.
+        const snap = await otherDb
+          .collection('coll-1')
+          .get({ source: 'cache' });
+        expect(toDataArray(snap)).to.deep.equal([
+          { k: 'a', bar: 1 },
+          { k: 'b', bar: 2 }
+        ]);
       });
     });
   });