Amplify DataStore: many-to-many join table not syncing when using selective sync

[stephenjen]

Description

I'm experiencing an issue with Amplify DataStore in a Flutter application. The main models (Share and OperationMode) are syncing correctly, but the automatically generated join table for a many-to-many relationship (ShareOperationMode) is not syncing to the device.

Here is the schema:

type Share @model @auth(rules: [{ allow: private, ownerField: "pOwner" }]) {
  id: ID!
  // ... other fields ...
  operationModes: [OperationMode] @manyToMany(relationName: "ShareOperationMode")
  pOwner: String!
}

type OperationMode @model @auth(rules: [{allow: private}]) {
  id: ID!
  // ... other fields ...
  shares: [Share] @manyToMany(relationName: "ShareOperationMode")
}

Here is the syncExpressions:

final syncExpressions = [
  DataStoreSyncExpression(Share.classType, 
    () => Share.POWNER.eq(prefs.getString('userId') ?? '')
      .or(Share.POWNER.isOneOf(prefs.getStringList('friendIds') ?? []))
  ),
  DataStoreSyncExpression(OperationMode.classType, () => QueryPredicate.all),
];

Categories

• Analytics
• API (REST)
• API (GraphQL)
• Auth
• Authenticator
• DataStore
• Notifications (Push)
• Storage

Steps to Reproduce

1. Add selective sync to Share model
2. Install app
3. Wait for sync to complete. After initial syncing, I run DataStore.close() to stop so sync expression can be loaded again to load records owned by user's friends
4. Share and OperationMode sync correctly, but ShareOperationMode does not sync and is left with zero records.

Screenshots

No response

Platforms

• iOS
• Android
• Web
• macOS
• Windows
• Linux

Flutter Version

3.24.0

Amplify Flutter Version

2.4.1

Deployment Method

Amplify CLI (Gen 1)

Schema

No response

[tyllark]

Hi @stephenjen, thank you for submitting this issue. We will take a look at this issue and get back to you when we have any updates or questions.

[stephenjen]

An update - I'm able to sync ShareOperationMode items for the owner but not for the owner's friends, even through I am able to sync owner's friends' Share items, which has a sync expression of Share.POWNER.isOneOf(prefs.getStringList('friendIds') ?? []).

[stephenjen]

An update - It works properly when I clear() as opposed to stop() before restarting DataStore to reevaluate sync expressions. Please make this work for stop() too, as having to wait for a clear() is quite impractical outside of the initial sync when users first install and get the app going.

Maybe there's a better way for me. My current use case: users can find and add friends in the app, and when they do, they can also see items owned by their friends. Currently I reevaluate sync expressions to enable this functionality, but is there a way to set up my schema so I can 1) accomplish the functionality I just described; and 2) do so without users having to carry around both their friends' and non-friends' items?

[stephenjen]

Any updates?

[khatruong2009]

@stephenjen, do you get this problem for Android too or is this only an issue you're having with iOS?

[stephenjen]

I'm only developing for iOS, so can only speak to it not working in iOS

[khatruong2009]

Hi @stephenjen, isOneOf isn't in our list of supported predicates. As an alternative to that, you could building a predicate group of or predicates that checks if POWNER is equal to each item of the prefs.getStringList('friendIds')

[stephenjen]

@khatruong2009 yes, that is a custom extension that essentially creates a series of .or() predicates.

I'm not sure this is the issue as this custom extension works for the Share and other models.

The issue seems to be when the sync expressions is reevaluated for Share, the automatically generated ShareOperationMode (the many to many join model) isn't updated.