fix(Model): retrieve correct associated target name

Amplify/Categories/DataStore/Model/Collection/List+LazyLoad.swift

@@ -31,21 +31,13 @@ extension List {
     internal func lazyLoad(_ completion: DataStoreCallback<Elements>) {
 
         // if the collection has no associated field, return the current elements
-        guard let associatedId = self.associatedId,
-              let associatedField = self.associatedField else {
+        guard let associatedId = associatedId,
+              let associatedField = associatedField else {
             completion(.success(elements))
             return
         }
 
-        // TODO: this is currently done by specific plugin implementations (API or DataStore)
-        // How to add this name resolution to Amplify?
-        let modelName = Element.modelName
-        var name = modelName.camelCased() + associatedField.name.pascalCased() + "Id"
-        if case let .belongsTo(_, targetName) = associatedField.association {
-            name = targetName ?? name
-        }
-
-        let predicate: QueryPredicate = field(name) == associatedId
+        let predicate: QueryPredicate = field(associatedField.name) == associatedId
         Amplify.DataStore.query(Element.self, where: predicate) {
             switch $0 {
             case .success(let elements):

AmplifyPlugins/API/AWSAPICategoryPluginFunctionalTests/GraphQLModelBased/GraphQLConnectionScenario1Tests.swift

@@ -171,7 +171,6 @@ class GraphQLConnectionScenario1Tests: XCTestCase {
         wait(for: [getProjectAfterDeleteCompleted], timeout: TestCommonConstants.networkTimeout)
     }
 
-    // TODO: This test will fail until https://github.com/aws-amplify/amplify-ios/pull/885 is merged in
     func testListProjectsByTeamID() {
         guard let team = createTeam(name: "name") else {
             XCTFail("Could not create team")

AmplifyPlugins/API/AWSAPICategoryPluginFunctionalTests/GraphQLModelBased/GraphQLConnectionScenario4Tests.swift

@@ -203,7 +203,6 @@ class GraphQLConnectionScenario4Tests: XCTestCase {
         wait(for: [getCommentAfterDeleteCompleted], timeout: TestCommonConstants.networkTimeout)
     }
 
-    // TODO: This test will fail until https://github.com/aws-amplify/amplify-ios/pull/885 is merged in
     func testListCommentsByPostID() {
         guard let post = createPost(title: "title") else {
             XCTFail("Could not create post")

AmplifyPlugins/API/AWSAPICategoryPluginFunctionalTests/GraphQLModelBased/GraphQLConnectionScenario5Tests.swift

@@ -65,7 +65,6 @@ class GraphQLConnectionScenario5Tests: XCTestCase {
         Amplify.reset()
     }
 
-    // TODO: This test will fail until https://github.com/aws-amplify/amplify-ios/pull/885 is merged in
     func testListPostEditorByPost() {
         guard let post = createPost(title: "title") else {
             XCTFail("Could not create post")
@@ -98,7 +97,6 @@ class GraphQLConnectionScenario5Tests: XCTestCase {
         wait(for: [listPostEditorByPostIDCompleted], timeout: TestCommonConstants.networkTimeout)
     }
 
-    // TODO: This test will fail until https://github.com/aws-amplify/amplify-ios/pull/885 is merged in
     func testListPostEditorByUser() {
         guard let post = createPost(title: "title") else {
             XCTFail("Could not create post")

AmplifyPlugins/Core/AWSPluginsCore/Model/GraphQLRequest/GraphQLRequest+AnyModelWithSync.swift

@@ -171,7 +171,7 @@ extension GraphQLRequest: ModelSyncGraphQLRequestFactory {
                                                                operationType: .query)
         documentBuilder.add(decorator: DirectiveNameDecorator(type: .sync))
         if let predicate = predicate {
-            documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter))
+            documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter(for: modelSchema)))
         }
         documentBuilder.add(decorator: PaginationDecorator(limit: limit, nextToken: nextToken))
         documentBuilder.add(decorator: ConflictResolutionDecorator(lastSync: lastSync))

AmplifyPlugins/Core/AWSPluginsCore/Model/GraphQLRequest/GraphQLRequest+Model.swift

@@ -169,12 +169,12 @@ extension GraphQLRequest: ModelGraphQLRequestFactory {
         case .delete:
             documentBuilder.add(decorator: ModelIdDecorator(id: model.id))
             if let predicate = predicate {
-                documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter))
+                documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter(for: modelSchema)))
             }
         case .update:
             documentBuilder.add(decorator: ModelDecorator(model: model))
             if let predicate = predicate {
-                documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter))
+                documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter(for: modelSchema)))
             }
         }
 
@@ -206,7 +206,7 @@ extension GraphQLRequest: ModelGraphQLRequestFactory {
         documentBuilder.add(decorator: DirectiveNameDecorator(type: .list))
 
         if let predicate = predicate {
-            documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter))
+            documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter(for: modelType.schema)))
         }
 
         documentBuilder.add(decorator: PaginationDecorator())

AmplifyPlugins/Core/AWSPluginsCore/Model/Support/QueryPredicate+GraphQL.swift

@@ -11,12 +11,35 @@ import Amplify
 public typealias GraphQLFilter = [String: Any]
 
 protocol GraphQLFilterConvertible {
-    var graphQLFilter: GraphQLFilter { get }
+    func graphQLFilter(for modelSchema: ModelSchema?) -> GraphQLFilter
 }
 
 // Convert QueryPredicate to GraphQLFilter JSON, and GraphQLFilter JSON to GraphQLFilter
 public struct GraphQLFilterConverter {
 
+    /// Serialize the translated GraphQL query variable object to JSON string.
+    /// - Warning: Although this has `public` access, it is intended for internal use and should not be used directly
+    ///   by host applications. The behavior of this may change without warning.
+    public static func toJSON(_ queryPredicate: QueryPredicate,
+                              modelSchema: ModelSchema,
+                              options: JSONSerialization.WritingOptions = []) throws -> String {
+        let graphQLFilterData =
+            try JSONSerialization.data(withJSONObject: queryPredicate.graphQLFilter(for: modelSchema),
+                                       options: options)
+
+        guard let serializedString = String(data: graphQLFilterData, encoding: .utf8) else {
+            preconditionFailure("""
+                Could not initialize String from the GraphQL representation of QueryPredicate:
+                \(String(describing: graphQLFilterData))
+                """)
+        }
+
+        return serializedString
+    }
+
+    @available(*, deprecated, message: """
+    Use `toJSON(_:modelSchema:options)` instead. See https://github.com/aws-amplify/amplify-ios/pull/965 for more details.
+    """)
     /// Serialize the translated GraphQL query variable object to JSON string.
     public static func toJSON(_ queryPredicate: QueryPredicate,
                               options: JSONSerialization.WritingOptions = []) throws -> String {
@@ -47,11 +70,27 @@ public struct GraphQLFilterConverter {
 /// Extension to translate a `QueryPredicate` into a GraphQL query variables object
 extension QueryPredicate {
 
+    /// - Warning: Although this has `public` access, it is intended for internal use and should not be used directly
+    ///   by host applications. The behavior of this may change without warning.
+    public func graphQLFilter(for modelSchema: ModelSchema?) -> GraphQLFilter {
+        if let operation = self as? QueryPredicateOperation {
+            return operation.graphQLFilter(for: modelSchema)
+        } else if let group = self as? QueryPredicateGroup {
+            return group.graphQLFilter(for: modelSchema)
+        }
+
+        preconditionFailure(
+            "Could not find QueryPredicateOperation or QueryPredicateGroup for \(String(describing: self))")
+    }
+
+    @available(*, deprecated, message: """
+    Use `graphQLFilter(for:)` instead. See https://github.com/aws-amplify/amplify-ios/pull/965 for more details.
+    """)
     public var graphQLFilter: GraphQLFilter {
         if let operation = self as? QueryPredicateOperation {
-            return operation.graphQLFilter
+            return operation.graphQLFilter(for: nil)
         } else if let group = self as? QueryPredicateGroup {
-            return group.graphQLFilter
+            return group.graphQLFilter(for: nil)
         }
 
         preconditionFailure(
@@ -60,30 +99,52 @@ extension QueryPredicate {
 }
 
 extension QueryPredicateOperation: GraphQLFilterConvertible {
-    var graphQLFilter: GraphQLFilter {
-        return [field: [self.operator.graphQLOperator: self.operator.value]]
+
+    func graphQLFilter(for modelSchema: ModelSchema?) -> GraphQLFilter {
+        let filterValue = [self.operator.graphQLOperator: self.operator.value]
+        guard let modelSchema = modelSchema else {
+            return [field: filterValue]
+        }
+        return [columnName(modelSchema): filterValue]
+    }
+
+    func columnName(_ modelSchema: ModelSchema) -> String {
+        guard let modelField = modelSchema.field(withName: field) else {
+            return field
+        }
+        let defaultFieldName = modelSchema.name.camelCased() + field.pascalCased() + "Id"
+        switch modelField.association {
+        case .belongsTo(_, let targetName):
+            return targetName ?? defaultFieldName
+        case .hasOne(_, let targetName):
+            return targetName ?? defaultFieldName
+        default:
+            return field
+        }
     }
 }
 
 extension QueryPredicateGroup: GraphQLFilterConvertible {
-    var graphQLFilter: GraphQLFilter {
+
+    func graphQLFilter(for modelSchema: ModelSchema?) -> GraphQLFilter {
         let logicalOperator = type.rawValue
         switch type {
         case .and, .or:
             var graphQLPredicateOperation = [logicalOperator: [Any]()]
             predicates.forEach { predicate in
-                graphQLPredicateOperation[logicalOperator]?.append(predicate.graphQLFilter)
+                graphQLPredicateOperation[logicalOperator]?.append(predicate.graphQLFilter(for: modelSchema))
             }
             return graphQLPredicateOperation
         case .not:
             if let predicate = predicates.first {
-                return [logicalOperator: predicate.graphQLFilter]
+                return [logicalOperator: predicate.graphQLFilter(for: modelSchema)]
             } else {
                 preconditionFailure("Missing predicate for \(String(describing: self)) with type: \(type)")
             }
         }
     }
 }
+
 extension QueryOperator {
     var graphQLOperator: String {
         switch self {

AmplifyPlugins/Core/AWSPluginsCoreTests/Model/GraphQLDocument/GraphQLListQueryTests.swift

@@ -43,7 +43,7 @@ class GraphQLListQueryTests: XCTestCase {
         var documentBuilder = ModelBasedGraphQLDocumentBuilder(modelSchema: Post.schema, operationType: .query)
         documentBuilder.add(decorator: DirectiveNameDecorator(type: .list))
         documentBuilder.add(decorator: PaginationDecorator())
-        documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter))
+        documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter(for: Post.schema)))
         let document = documentBuilder.build()
         let expectedQueryDocument = """
         query ListPosts($filter: ModelPostFilterInput, $limit: Int) {
@@ -115,14 +115,75 @@ class GraphQLListQueryTests: XCTestCase {
         XCTAssertEqual(String(data: filterJSON!, encoding: .utf8), expectedFilterJSON)
     }
 
+    func testComment4BelongsToPost4Success() {
+        let comment4 = Comment4.keys
+        let predicate = comment4.id == "comment4Id" && comment4.post == "post4Id"
+
+        var documentBuilder = ModelBasedGraphQLDocumentBuilder(modelSchema: Comment4.schema,
+                                                               operationType: .query)
+        documentBuilder.add(decorator: DirectiveNameDecorator(type: .list))
+        documentBuilder.add(decorator: PaginationDecorator())
+        documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter(for: Comment4.schema)))
+        let document = documentBuilder.build()
+        let expectedQueryDocument = """
+        query ListComment4s($filter: ModelComment4FilterInput, $limit: Int) {
+          listComment4s(filter: $filter, limit: $limit) {
+            items {
+              id
+              content
+              postID
+              __typename
+            }
+            nextToken
+          }
+        }
+        """
+        XCTAssertEqual(document.name, "listComment4s")
+        XCTAssertEqual(document.stringValue, expectedQueryDocument)
+        guard let variables = document.variables else {
+            XCTFail("The document doesn't contain variables")
+            return
+        }
+        XCTAssertNotNil(variables["limit"])
+        XCTAssertEqual(variables["limit"] as? Int, 1_000)
+
+        guard let filter = variables["filter"] as? GraphQLFilter else {
+            XCTFail("variables should contain a valid filter")
+            return
+        }
+
+        // Test filter for a valid JSON format
+        let filterJSON = try? JSONSerialization.data(withJSONObject: filter,
+                                                     options: .prettyPrinted)
+        XCTAssertNotNil(filterJSON)
+
+        let expectedFilterJSON = """
+        {
+          "and" : [
+            {
+              "id" : {
+                "eq" : "comment4Id"
+              }
+            },
+            {
+              "postID" : {
+                "eq" : "post4Id"
+              }
+            }
+          ]
+        }
+        """
+        XCTAssertEqual(String(data: filterJSON!, encoding: .utf8), expectedFilterJSON)
+    }
+
     func testListGraphQLQueryFromSimpleModelWithSyncEnabled() {
         let post = Post.keys
         let predicate = post.id.eq("id") && (post.title.beginsWith("Title") || post.content.contains("content"))
 
         var documentBuilder = ModelBasedGraphQLDocumentBuilder(modelSchema: Post.schema, operationType: .query)
         documentBuilder.add(decorator: DirectiveNameDecorator(type: .list))
         documentBuilder.add(decorator: PaginationDecorator())
-        documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter))
+        documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter(for: Post.schema)))
         documentBuilder.add(decorator: ConflictResolutionDecorator())
         let document = documentBuilder.build()
         let expectedQueryDocument = """

AmplifyPlugins/Core/AWSPluginsCoreTests/Model/GraphQLDocument/GraphQLSyncQueryTests.swift

@@ -38,7 +38,7 @@ class GraphQLSyncQueryTests: XCTestCase {
 
         var documentBuilder = ModelBasedGraphQLDocumentBuilder(modelSchema: Post.schema, operationType: .query)
         documentBuilder.add(decorator: DirectiveNameDecorator(type: .sync))
-        documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter))
+        documentBuilder.add(decorator: FilterDecorator(filter: predicate.graphQLFilter(for: Post.schema)))
         documentBuilder.add(decorator: PaginationDecorator(limit: 100, nextToken: "token"))
         documentBuilder.add(decorator: ConflictResolutionDecorator(lastSync: 123))
         let document = documentBuilder.build()