feat(api): add support for GraphQL filter attributeExists (#3838)

* add support for GraphQL filter attributeExists

* fix(datastore): deduplicate SQL statement of attributeExists and eq/ne

* fix(datastore): flacky unit test

Amplify/Categories/DataStore/Model/Internal/Persistable.swift

@@ -65,6 +65,12 @@ struct PersistableHelper {
             return lhs == rhs
         case let (lhs, rhs) as (String, String):
             return lhs == rhs
+        case let (lhs, rhs) as (any EnumPersistable, String):
+            return lhs.rawValue == rhs
+        case let (lhs, rhs) as (String, any EnumPersistable):
+            return lhs == rhs.rawValue
+        case let (lhs, rhs) as (any EnumPersistable, any EnumPersistable):
+            return lhs.rawValue == rhs.rawValue
         default:
             return false
         }
@@ -94,6 +100,12 @@ struct PersistableHelper {
             return lhs == Double(rhs)
         case let (lhs, rhs) as (String, String):
             return lhs == rhs
+        case let (lhs, rhs) as (any EnumPersistable, String):
+            return lhs.rawValue == rhs
+        case let (lhs, rhs) as (String, any EnumPersistable):
+            return lhs == rhs.rawValue
+        case let (lhs, rhs) as (any EnumPersistable, any EnumPersistable):
+            return lhs.rawValue == rhs.rawValue
         default:
             return false
         }
@@ -122,6 +134,12 @@ struct PersistableHelper {
             return lhs <= Double(rhs)
         case let (lhs, rhs) as (String, String):
             return lhs <= rhs
+        case let (lhs, rhs) as (any EnumPersistable, String):
+            return lhs.rawValue <= rhs
+        case let (lhs, rhs) as (String, any EnumPersistable):
+            return lhs <= rhs.rawValue
+        case let (lhs, rhs) as (any EnumPersistable, any EnumPersistable):
+            return lhs.rawValue <= rhs.rawValue
         default:
             return false
         }
@@ -150,6 +168,12 @@ struct PersistableHelper {
             return lhs < Double(rhs)
         case let (lhs, rhs) as (String, String):
             return lhs < rhs
+        case let (lhs, rhs) as (any EnumPersistable, String):
+            return lhs.rawValue < rhs
+        case let (lhs, rhs) as (String, any EnumPersistable):
+            return lhs < rhs.rawValue
+        case let (lhs, rhs) as (any EnumPersistable, any EnumPersistable):
+            return lhs.rawValue < rhs.rawValue
         default:
             return false
         }
@@ -178,6 +202,12 @@ struct PersistableHelper {
             return lhs >= Double(rhs)
         case let (lhs, rhs) as (String, String):
             return lhs >= rhs
+        case let (lhs, rhs) as (any EnumPersistable, String):
+            return lhs.rawValue >= rhs
+        case let (lhs, rhs) as (String, any EnumPersistable):
+            return lhs >= rhs.rawValue
+        case let (lhs, rhs) as (any EnumPersistable, any EnumPersistable):
+            return lhs.rawValue >= rhs.rawValue
         default:
             return false
         }
@@ -206,6 +236,12 @@ struct PersistableHelper {
             return Double(lhs) > rhs
         case let (lhs, rhs) as (String, String):
             return lhs > rhs
+        case let (lhs, rhs) as (any EnumPersistable, String):
+            return lhs.rawValue > rhs
+        case let (lhs, rhs) as (String, any EnumPersistable):
+            return lhs > rhs.rawValue
+        case let (lhs, rhs) as (any EnumPersistable, any EnumPersistable):
+            return lhs.rawValue > rhs.rawValue
         default:
             return false
         }

Amplify/Categories/DataStore/Query/ModelKey.swift

@@ -36,6 +36,11 @@ public protocol ModelKey: CodingKey, CaseIterable, QueryFieldOperation {}
 
 extension CodingKey where Self: ModelKey {
 
+    // MARK: - attributeExists
+    public func attributeExists(_ value: Bool) -> QueryPredicateOperation {
+        return field(stringValue).attributeExists(value)
+    }
+
     // MARK: - beginsWith
     public func beginsWith(_ value: String) -> QueryPredicateOperation {
         return field(stringValue).beginsWith(value)

Amplify/Categories/DataStore/Query/QueryField.swift

@@ -30,7 +30,7 @@ public func field(_ name: String) -> QueryField {
 /// - seealso: `ModelKey`
 public protocol QueryFieldOperation {
     // MARK: - Functions
-
+    func attributeExists(_ value: Bool) -> QueryPredicateOperation
     func beginsWith(_ value: String) -> QueryPredicateOperation
     func between(start: Persistable, end: Persistable) -> QueryPredicateOperation
     func contains(_ value: String) -> QueryPredicateOperation
@@ -61,6 +61,11 @@ public struct QueryField: QueryFieldOperation {
 
     public let name: String
 
+    // MARK: - attributeExists
+    public func attributeExists(_ value: Bool) -> QueryPredicateOperation {
+        return QueryPredicateOperation(field: name, operator: .attributeExists(value))
+    }
+
     // MARK: - beginsWith
     public func beginsWith(_ value: String) -> QueryPredicateOperation {
         return QueryPredicateOperation(field: name, operator: .beginsWith(value))

Amplify/Categories/DataStore/Query/QueryOperator+Equatable.swift

@@ -24,6 +24,8 @@ extension QueryOperator: Equatable {
         case let (.between(oneStart, oneEnd), .between(otherStart, otherEnd)):
             return PersistableHelper.isEqual(oneStart, otherStart)
                 && PersistableHelper.isEqual(oneEnd, otherEnd)
+        case let (.attributeExists(one), .attributeExists(other)):
+            return one == other
         default:
             return false
         }

Amplify/Categories/DataStore/Query/QueryOperator.swift

@@ -18,8 +18,9 @@ public enum QueryOperator: Encodable {
     case notContains(_ value: String)
     case between(start: Persistable, end: Persistable)
     case beginsWith(_ value: String)
+    case attributeExists(_ value: Bool)
 
-    public func evaluate(target: Any) -> Bool {
+    public func evaluate(target: Any?) -> Bool {
         switch self {
         case .notEqual(let predicateValue):
             return !PersistableHelper.isEqual(target, predicateValue)
@@ -34,20 +35,26 @@ public enum QueryOperator: Encodable {
         case .greaterThan(let predicateValue):
             return PersistableHelper.isGreaterThan(target, predicateValue)
         case .contains(let predicateString):
-            if let targetString = target as? String {
+            if let targetString = target.flatMap({ $0 as? String }) {
                 return targetString.contains(predicateString)
             }
             return false
         case .notContains(let predicateString):
-            if let targetString = target as? String {
+            if let targetString = target.flatMap({ $0 as? String }) {
                 return !targetString.contains(predicateString)
             }
         case .between(let start, let end):
             return PersistableHelper.isBetween(start, end, target)
         case .beginsWith(let predicateValue):
-            if let targetString = target as? String {
+            if let targetString = target.flatMap({ $0 as? String }) {
                 return targetString.starts(with: predicateValue)
             }
+        case .attributeExists(let predicateValue):
+            if case .some = target {
+                return predicateValue == true
+            } else {
+                return predicateValue == false
+            }
         }
         return false
     }
@@ -105,6 +112,10 @@ public enum QueryOperator: Encodable {
         case .beginsWith(let value):
             try container.encode("beginsWith", forKey: .type)
             try container.encode(value, forKey: .value)
+
+        case .attributeExists(let value):
+            try container.encode("attributeExists", forKey: .type)
+            try container.encode(value, forKey: .value)
         }
     }
 }

Amplify/Categories/DataStore/Query/QueryPredicate.swift

@@ -155,34 +155,6 @@ public class QueryPredicateOperation: QueryPredicate, Encodable {
     }
 
     public func evaluate(target: Model) -> Bool {
-        guard let fieldValue = target[field] else {
-            return false
-        }
-
-        guard let value = fieldValue else {
-            return false
-        }
-
-        if let booleanValue = value as? Bool {
-            return self.operator.evaluate(target: booleanValue)
-        }
-
-        if let doubleValue = value as? Double {
-            return self.operator.evaluate(target: doubleValue)
-        }
-
-        if let intValue = value as? Int {
-            return self.operator.evaluate(target: intValue)
-        }
-
-        if let timeValue = value as? Temporal.Time {
-            return self.operator.evaluate(target: timeValue)
-        }
-
-        if let enumValue = value as? EnumPersistable {
-            return self.operator.evaluate(target: enumValue.rawValue)
-        }
-
-        return self.operator.evaluate(target: value)
+        return self.operator.evaluate(target: target[field]?.flatMap { $0 })
     }
 }

AmplifyPlugins/API/Tests/APIHostApp/AWSAPIPluginFunctionalTests/GraphQLModelBasedTests+List.swift

@@ -145,4 +145,56 @@ extension GraphQLModelBasedTests {
             XCTAssertNotNil(error)
         }
     }
+
+    /**
+     - Given: API with Post schema and optional field 'draft'
+     - When:
+        - create a new post with optional field 'draft' value .none
+     - Then:
+        - query Posts with filter {eq : null} shouldn't include the post
+     */
+    func test_listModelsWithNilOptionalField_failedWithEqFilter() async throws {
+        let post = Post(title: UUID().uuidString, content: UUID().uuidString, createdAt: .now())
+        _ = try await Amplify.API.mutate(request: .create(post))
+        let posts = try await list(.list(
+            Post.self,
+            where: Post.keys.draft == nil && Post.keys.createdAt >= post.createdAt
+        ))
+
+        XCTAssertFalse(posts.map(\.id).contains(post.id))
+    }
+
+    /**
+     - Given: DataStore with Post schema and optional field 'draft'
+     - When:
+        - create a new post with optional field 'draft' value .none
+     - Then:
+        - query Posts with filter {attributeExists : false} should include the post
+     */
+    func test_listModelsWithNilOptionalField_successWithAttributeExistsFilter() async throws {
+        let post = Post(title: UUID().uuidString, content: UUID().uuidString, createdAt: .now())
+        _ = try await Amplify.API.mutate(request: .create(post))
+        let listPosts = try await list(
+            .list(
+                Post.self,
+                where: Post.keys.draft.attributeExists(false) 
+                    && Post.keys.createdAt >= post.createdAt
+            )
+        )
+
+        XCTAssertTrue(listPosts.map(\.id).contains(post.id))
+    }
+
+    func list<M: Model>(_ request: GraphQLRequest<List<M>>) async throws -> [M] {
+        func getAllPages(_ list: List<M>) async throws -> [M] {
+            if list.hasNextPage() {
+                return list.elements + (try await getAllPages(list.getNextPage()))
+            } else {
+                return list.elements
+            }
+        }
+
+        return try await getAllPages(try await Amplify.API.query(request: request).get())
+    }
+
 }

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

@@ -187,6 +187,8 @@ extension QueryOperator {
             return "beginsWith"
         case .notContains:
             return "notContains"
+        case .attributeExists:
+            return "attributeExists"
         }
     }
 
@@ -212,6 +214,8 @@ extension QueryOperator {
             return value
         case .notContains(let value):
             return value
+        case .attributeExists(let value):
+            return value
         }
     }
 }

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

@@ -218,4 +218,88 @@ class GraphQLListQueryTests: XCTestCase {
         XCTAssertEqual(variables["limit"] as? Int, 1_000)
         XCTAssertNotNil(variables["filter"])
     }
+
+    /**
+     - Given: 
+        - A Post schema with optional field 'draft'
+     - When:
+        - Using list query to filter records that either don't have 'draft' field or have 'null' value
+     - Then:
+        - the query document as expected
+        - the filter is encoded correctly
+     */
+    func test_listQuery_withAttributeExistsFilter_correctlyBuildGraphQLQueryStatement() {
+        let post = Post.keys
+        let predicate = post.id.eq("id")
+        && (post.draft.attributeExists(false) || post.draft.eq(nil))
+
+        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(for: Post.schema)))
+        let document = documentBuilder.build()
+        let expectedQueryDocument = """
+        query ListPosts($filter: ModelPostFilterInput, $limit: Int) {
+          listPosts(filter: $filter, limit: $limit) {
+            items {
+              id
+              content
+              createdAt
+              draft
+              rating
+              status
+              title
+              updatedAt
+              __typename
+            }
+            nextToken
+          }
+        }
+        """
+        XCTAssertEqual(document.name, "listPosts")
+        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" : "id"
+              }
+            },
+            {
+              "or" : [
+                {
+                  "draft" : {
+                    "attributeExists" : false
+                  }
+                },
+                {
+                  "draft" : {
+                    "eq" : null
+                  }
+                }
+              ]
+            }
+          ]
+        }
+        """
+        XCTAssertEqual(String(data: filterJSON!, encoding: .utf8), expectedFilterJSON)
+    }
 }

AmplifyPlugins/Core/AWSPluginsCoreTests/Query/QueryPredicateEvaluateGeneratedBoolTests.swift

@@ -41,7 +41,7 @@ class QueryPredicateEvaluateGeneratedBoolTests: XCTestCase {
 
         let evaluation = try predicate.evaluate(target: instance.eraseToAnyModel().instance)
 
-        XCTAssertFalse(evaluation)
+        XCTAssertTrue(evaluation)
     }
 
     func testBoolfalsenotEqualBooltrue() throws {
@@ -70,7 +70,7 @@ class QueryPredicateEvaluateGeneratedBoolTests: XCTestCase {
 
         let evaluation = try predicate.evaluate(target: instance.eraseToAnyModel().instance)
 
-        XCTAssertFalse(evaluation)
+        XCTAssertTrue(evaluation)
     }
 
     func testBooltrueequalsBooltrue() throws {