Android's mutation selection set is incompatible with iOS' subscription handling #1772
Description
Before opening, please confirm:
- I have searched for duplicate or closed issues and discussions.
Language and Async Model
Not applicable
Amplify Categories
DataStore
Gradle script dependencies
N/A
Environment information
N/A
Please include any relevant guides or documentation you're referencing
No response
Describe the bug
From @Amplifiyer:
While testing the sync between local and remote, there is some weird behavior between how it works in iOS and Android. The selection set of the create mutations in iOS seem to include the full nested model fields, while in android it’s only the ID. So for instance if I create two mutations from AppSync as follows:
mutation OnlyIdMutation {
createPost(input: {blogID: "6a83a3b4-2b82-4dfa-8b58-5e32326865a2", rating: 10, title: "Remote blog 6"}) {
_deleted
_lastChangedAt
_version
blogID
created
createdAt
id
rating
title
updatedAt
blog {
id
}
}
}and
mutation FullNestedModelMutation {
createPost(input: {blogID: "6a83a3b4-2b82-4dfa-8b58-5e32326865a2", rating: 10, title: "Remote blog 6"}) {
_deleted
_lastChangedAt
_version
blogID
created
createdAt
id
rating
title
updatedAt
blog {
id
updatedAt
name
createdAt
_version
_lastChangedAt
_deleted
}
}
}Both are successful on Android, but only the later works on iOS. The first one will result in some GraphQL errors on the iOS client:
{
"id": "2ACF986E-7607-4CD7-AEE3-148F34B01183",
"type": "data",
"payload": {
"data": {
"onCreatePost": {
"id": "909fccc6-7ad3-4408-8b49-23616123413e",
"created": null,
"rating": 3,
"title": "Post 2 android\t",
"blog": null,
"__typename": "Post",
"_version": 1,
"_deleted": null,
"_lastChangedAt": 1606251462643
}
},
"errors": [
{
"message": "Cannot return null for non-nullable type: 'String' within parent 'Blog' (/onCreatePost/blog/name)",
"path": [
"onCreatePost",
"blog",
"name"
]
},
{
"message": "Cannot return null for non-nullable type: 'Int' within parent 'Blog' (/onCreatePost/blog/_version)",
"path": [
"onCreatePost",
"blog",
"_version"
]
},
{
"message": "Cannot return null for non-nullable type: 'AWSTimestamp' within parent 'Blog' (/onCreatePost/blog/_lastChangedAt)",
"path": [
"onCreatePost",
"blog",
"_lastChangedAt"
]
}
]
}
}Reproduction steps (if applicable)
No response
Code Snippet
No response
Log output
No response
amplifyconfiguration.json
No response
GraphQL Schema
No response
Additional information and screenshots
A few notes on the issue:
- We have a toggle for this behavior, when making GraphQL requests. The DataStore category only includes requests IDs from children, and the API category requests all fields.
- It’s breaking in iOS most likely because the underlying model is required or has required properties. Swift is very strict when deserializing JSON since types declared as required must be provided at creation time. You can’t do
name: String!and then not provide it when constructing the object.