"Validation error of type SubSelectionRequired" during sync

I am having trouble syncing with Datastore.

Here is a snippet of our schema:

interface IEntity {
  id: ID!
  insightsId: Int
}

interface ITask {
  insightsId: Int
  type: TaskType!
  createdAt: AWSDateTime!
  updatedAt: AWSDateTime!
  comment: String
  dueDate: AWSDateTime
  isAnytime: Boolean
  customerId: ID
  assigneeName: String!
  editedBy: String!
  reminder: Reminder
}

type Task implements ITask & IEntity {
  id: ID!
  insightsId: Int
  type: TaskType!
  createdAt: AWSDateTime!
  updatedAt: AWSDateTime!
  comment: String
  dueDate: AWSDateTime
  isAnytime: Boolean
  customerId: ID
  assigneeName: String!
  editedBy: String!
  reminder: Reminder
  visitId: Int
  endTime: String
  _version: Int!
  _deleted: Boolean
  _lastChangedAt: AWSTimestamp!
}

type Reminder {
  offSet: String
  date: AWSDateTime
}

enum TaskType {
  TASK
  SCHEDULED
}

When the app starts up with a valid signed-in user, the app shows the following log output:

W/amplify:aws-datastore: Failed to sync down cloud state for model type = Task
AmplifyException {message=Failure performing sync query to AppSync: [GraphQLResponse.Error{message='Validation error of type SubSelectionRequired: Sub selection required for type Reminder of field reminder @ 'syncTasks/items/reminder'', locations='[GraphQLLocation{line='14', column='7'}]', path='null', extensions='null'}], cause=null, recoverySuggestion=Sorry, we don't have a suggested fix for this error yet.}
        at com.amplifyframework.datastore.appsync.AppSyncClient.lambda$sync$0$AppSyncClient(AppSyncClient.java:107)
        at com.amplifyframework.datastore.appsync.-$$Lambda$AppSyncClient$DAlM2A4r8A_52MV-BaSjc1SYWao.accept(lambda)
        at com.amplifyframework.api.aws.AppSyncGraphQLOperation$OkHttpCallback.onResponse(AppSyncGraphQLOperation.java:140)
        at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:504)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:761)

It looks a lot like https://github.com/aws-amplify/amplify-ios/issues/529, marked as closed in the iOS library.

When I run a Task query on the AppSync query page, it seems to respond with the correct data (though it looks like the editor specifies the leaf fields for you).

More log context:

2020-08-06 08:45:38.032 8214-8947/com.skynamo.appid W/amplify:aws-datastore: Failed to sync down cloud state for model type = Task
    AmplifyException {message=Failure performing sync query to AppSync: [GraphQLResponse.Error{message='Validation error of type SubSelectionRequired: Sub selection required for type Reminder of field reminder @ 'syncTasks/items/reminder'', locations='[GraphQLLocation{line='14', column='7'}]', path='null', extensions='null'}], cause=null, recoverySuggestion=Sorry, we don't have a suggested fix for this error yet.}
        at com.amplifyframework.datastore.appsync.AppSyncClient.lambda$sync$0$AppSyncClient(AppSyncClient.java:107)
        at com.amplifyframework.datastore.appsync.-$$Lambda$AppSyncClient$DAlM2A4r8A_52MV-BaSjc1SYWao.accept(lambda)
        at com.amplifyframework.api.aws.AppSyncGraphQLOperation$OkHttpCallback.onResponse(AppSyncGraphQLOperation.java:140)
        at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:504)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:761)
2020-08-06 08:45:38.032 8214-8947/com.skynamo.appid W/amplify:aws-datastore: Initial cloud sync failed.
    AmplifyException {message=Failure performing sync query to AppSync: [GraphQLResponse.Error{message='Validation error of type SubSelectionRequired: Sub selection required for type Reminder of field reminder @ 'syncTasks/items/reminder'', locations='[GraphQLLocation{line='14', column='7'}]', path='null', extensions='null'}], cause=null, recoverySuggestion=Sorry, we don't have a suggested fix for this error yet.}
        at com.amplifyframework.datastore.appsync.AppSyncClient.lambda$sync$0$AppSyncClient(AppSyncClient.java:107)
        at com.amplifyframework.datastore.appsync.-$$Lambda$AppSyncClient$DAlM2A4r8A_52MV-BaSjc1SYWao.accept(lambda)
        at com.amplifyframework.api.aws.AppSyncGraphQLOperation$OkHttpCallback.onResponse(AppSyncGraphQLOperation.java:140)
        at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:504)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:761)
2020-08-06 08:45:38.032 8214-8947/com.skynamo.appid E/amplify:aws-datastore: Error encountered in the DataStore.
    AmplifyException {message=Initial cloud sync failed., cause=AmplifyException {message=Failure performing sync query to AppSync: [GraphQLResponse.Error{message='Validation error of type SubSelectionRequired: Sub selection required for type Reminder of field reminder @ 'syncTasks/items/reminder'', locations='[GraphQLLocation{line='14', column='7'}]', path='null', extensions='null'}], cause=null, recoverySuggestion=Sorry, we don't have a suggested fix for this error yet.}, recoverySuggestion=Check your internet connection.}
        at com.amplifyframework.datastore.syncengine.SyncProcessor.lambda$null$2$SyncProcessor(SyncProcessor.java:122)
        at com.amplifyframework.datastore.syncengine.-$$Lambda$SyncProcessor$3L2KTfMEy6_59oCr_DedPu68KAo.accept(lambda)
        at io.reactivex.internal.operators.completable.CompletablePeek$CompletableObserverImplementation.onError(CompletablePeek.java:88)
        at io.reactivex.internal.operators.completable.CompletableAndThenCompletable$SourceObserver.onError(CompletableAndThenCompletable.java:62)
        at io.reactivex.internal.operators.single.SingleFlatMapCompletable$FlatMapCompletableObserver.onError(SingleFlatMapCompletable.java:97)
        at io.reactivex.internal.operators.observable.ObservableFlatMapCompletableCompletable$FlatMapCompletableMainObserver.onError(ObservableFlatMapCompletableCompletable.java:126)
        at io.reactivex.internal.operators.observable.ObservableFlattenIterable$FlattenIterableObserver.onError(ObservableFlattenIterable.java:125)
        at io.reactivex.internal.observers.BasicFuseableObserver.onError(BasicFuseableObserver.java:100)
        at io.reactivex.internal.operators.observable.ObservableToList$ToListObserver.onError(ObservableToList.java:92)
        at io.reactivex.internal.operators.mixed.SingleFlatMapObservable$FlatMapObserver.onError(SingleFlatMapObservable.java:74)
        at io.reactivex.internal.operators.single.SingleDoOnError$DoOnError.onError(SingleDoOnError.java:63)
        at io.reactivex.internal.operators.single.SingleDoOnSuccess$DoOnSuccess.onError(SingleDoOnSuccess.java:65)
        at io.reactivex.internal.operators.single.SingleCreate$Emitter.tryOnError(SingleCreate.java:94)
        at io.reactivex.internal.operators.single.SingleCreate$Emitter.onError(SingleCreate.java:80)
        at com.amplifyframework.datastore.syncengine.-$$Lambda$3TQsNIUgAvjdYqsJiM71fw48re0.accept(lambda)
        at com.amplifyframework.datastore.appsync.AppSyncClient.lambda$sync$0$AppSyncClient(AppSyncClient.java:106)
        at com.amplifyframework.datastore.appsync.-$$Lambda$AppSyncClient$DAlM2A4r8A_52MV-BaSjc1SYWao.accept(lambda)
        at com.amplifyframework.api.aws.AppSyncGraphQLOperation$OkHttpCallback.onResponse(AppSyncGraphQLOperation.java:140)
        at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:504)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:761)
     Caused by: AmplifyException {message=Failure performing sync query to AppSync: [GraphQLResponse.Error{message='Validation error of type SubSelectionRequired: Sub selection required for type Reminder of field reminder @ 'syncTasks/items/reminder'', locations='[GraphQLLocation{line='14', column='7'}]', path='null', extensions='null'}], cause=null, recoverySuggestion=Sorry, we don't have a suggested fix for this error yet.}
        at com.amplifyframework.datastore.appsync.AppSyncClient.lambda$sync$0$AppSyncClient(AppSyncClient.java:107)
        at com.amplifyframework.datastore.appsync.-$$Lambda$AppSyncClient$DAlM2A4r8A_52MV-BaSjc1SYWao.accept(lambda) 
        at com.amplifyframework.api.aws.AppSyncGraphQLOperation$OkHttpCallback.onResponse(AppSyncGraphQLOperation.java:140) 
        at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:504) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
        at java.lang.Thread.run(Thread.java:761) 
2020-08-06 08:45:38.034 8214-8679/com.skynamo.appid I/amplify:aws-datastore: Starting processing subscription data buffer.

[endigo]

@jpignata Hey is it included in 1.3.1? I think it’s not included in this version.

[jamesonwilliams]

#801 went out in 1.3.2. Please give this latest version a try, and let us know if the issue persists.