GraphQL Transformer issue when using custom @key and @connection

[drochetti]

Problem:

When defining schemas with custom keys, or explicit keys defined along with a field with a @connection directive, the GraphQL transformer expects that the input object of a mutation provide both the id/key and the connected type Input.

Example:

• Given the following schema

type Post @model {
    id: ID!
    title: String!
    editors: [PostEditor] @connection(keyName: "byPost", fields: ["id"])
}

# Create a join model and disable queries as you don't need them
# and can query through Post.editors and User.posts
type PostEditor
    @model(queries: null)
    @key(name: "byPost", fields: ["postID", "editorID"])
    @key(name: "byEditor", fields: ["editorID", "postID"]) {
    id: ID!
    postID: ID!
    editorID: ID!
    post: Post! @connection(fields: ["postID"])
    editor: User! @connection(fields: ["editorID"])
}

type User @model {
    id: ID!
    username: String!
    posts: [PostEditor] @connection(keyName: "byEditor", fields: ["id"])
}

• The GraphQL transformer generates the following input for PostEditor:

input PostEditorInput {
	id: ID!
	postID: ID!
	editorID: ID!
	post: PostInput!
}

# ps: omitting the conflict resolution fields _version, _deleted, _lastChangedAt
# since they are not relevant to this issue

A few notes from the generated input:

1. postID accounts for the connection between Post and PostEditor, so I believe post: PostInput! should not be there, regardless of it's optional or not, given that cascade writes are not supported as of now (is that a fair assumption?)
2. editorID is there, but editor: UserInput! is not, which seems inconsistent given how postID and post: PostInput! was handled
3. In a scenario where postID and editorID were not explicitly defined, I would expect the input to have postEditorPostId and postEditorUserId automatically generated, but in no scenario post: PostInput! should be there. Is that correct?

Scenario 1: Customs keys

The expected transformed input is:

input PostEditorInput {
	id: ID!
	postID: ID!
	editorID: ID!
}

Scenario 2: Connections with no custom keys

The expected transformed input is:

input PostEditorInput {
	id: ID!
	postEditorPostId: ID!
	postEditorUserId: ID!
}

Possible related issues:

• Create mutation fails with datastore - not adding belongsTo parent id to input amplify-swift#298

[yuth]

1. `postID` accounts for the connection between `Post` and `PostEditor`, so I believe `post: PostInput!` should not be there, regardless of it's optional or not, given that cascade writes are not supported as of now (is that a fair assumption?)

Yes this is a bug in the graphql-transformer

3\. In a scenario where `postID` and `editorID` were not explicitly defined, I would expect the input to have `postEditorPostId` and `postEditorUserId` automatically generated, but in no scenario `post: PostInput!` should be there. Is that correct?

Yes, This should work when using named connections. When using @connection with fields those fields have to be explicitly defined in the type

[undefobj]

Duplicate of #3438

[attilah]

Closing in favor of #3438

[github-actions]

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