INSERT statements should not return an optional

Author: wickwirew

Sources/Compiler/Gen/Language.swift

@@ -264,7 +264,8 @@ extension Language {
         // Will return an array if it returns many or optional if its a single result
         let singleOrMany: (GenerationType) -> GenerationType = {
             switch statement.outputCardinality {
-            case .single: .optional($0)
+            // INSERTs will always return a value so no need to do optional
+            case .single: statement.isInsert ? $0 : .optional($0)
             case .many: .array($0)
             }
         }

Sources/Compiler/Gen/SwiftLanguage.swift

@@ -244,7 +244,25 @@ public struct SwiftLanguage: Language {
         writer.write(line: "init(")
         writer.indent()
         for (position, query) in queries.positional() {
-            writer.write(line: query.variableName, ": any ", query.typealiasName, " = Queries.Just()")
+            writer.write(line: query.variableName, ": any ", query.typealiasName)
+            
+            switch query.output {
+            case .model:
+                // We might be able to initialize one in the future with all default values
+                // but it seems hacky so just fail
+                writer.write(" = Queries.Fail()")
+            case .builtin(let name):
+                let defaultValue = switch name {
+                case "Double": "0.0"
+                case "Int": "0"
+                case "String": "\"\""
+                case "Data": "Data()"
+                default: "SQLAny.int(0)"
+                }
+                writer.write(" = Queries.Just(", defaultValue, ")")
+            default:
+                writer.write(" = Queries.Just()")
+            }
 
             if !position.isLast {
                 writer.write(",")

Sources/Compiler/Sema/Statement.swift

@@ -37,6 +37,13 @@ public struct Statement {
         return definition?.name
     }
 
+    /// Whether or not the source syntax is an INSERT statement
+    public var isInsert: Bool {
+        if syntax is InsertStmtSyntax { return true }
+        guard let definition = syntax as? QueryDefinitionStmtSyntax else { return false }
+        return definition.statement is InsertStmtSyntax
+    }
+    
     /// Replaces the definition with the given input
     public func with(definition: Definition?) -> Statement {
         return Statement(

Sources/Otter/Queries/Fail.swift

@@ -13,6 +13,9 @@ public extension Queries {
         /// The error to throw on execution
         let error: any Error
 
+        /// The default error to throw if none is provided
+        struct FailError: Error {}
+        
         /// Initializes a query that always fails with an error.
         /// This is useful for unit tests and previews to test
         /// how a part of an application behaives when an error
@@ -23,6 +26,14 @@ public extension Queries {
             self.error = error
         }
 
+        /// Initializes a query that always fails with an error.
+        /// This is useful for unit tests and previews to test
+        /// how a part of an application behaives when an error
+        /// is thrown.
+        public init() {
+            self.error = FailError()
+        }
+        
         public var transactionKind: Transaction.Kind { .read }
         public var watchedTables: Set<String> { [] }
         public var connection: any Connection { NoopConnection() }

Sources/Otter/Statement.swift

@@ -103,11 +103,21 @@ public struct Statement: ~Copyable {
         return result
     }
 
-    /// Fetches a single row returned by the statement
+    /// Optionally fetches a single row returned by the statement
     public consuming func fetchOne<T: RowDecodable>() throws(OtterError) -> T? {
         return try fetchOne(of: T.self)
     }
 
+    /// Fetches a single row returned by the statement
+    @_disfavoredOverload
+    public consuming func fetchOne<T: RowDecodable>() throws(OtterError) -> T {
+        guard let row = try fetchOne(of: T.self) else {
+            throw OtterError.queryReturnedNoValue
+        }
+        
+        return row
+    }
+    
     /// Fetches a single row returned by the statement
     public consuming func fetchOne<T: RowDecodable>(
         of _: T.Type

Tests/CompilerTests/Gen/Queries.sql

@@ -1,5 +1,5 @@
 insertUser:
-INSERT INTO user VALUES (?, ?, ?, ?, ?, ?, ?);
+INSERT INTO user VALUES (?, ?, ?, ?, ?, ?, ?) RETURNING id;
 
 selectUsers:
 SELECT * FROM user;

Tests/CompilerTests/Gen/Swift.output

@@ -203,7 +203,7 @@ protocol QueriesQueries: ConnectionWrapper {
 
 struct QueriesQueriesNoop: QueriesQueries {
     let connection: any Connection = NoopConnection()
-    let insertUser: AnyQuery<InsertUserInput, ()>
+    let insertUser: AnyQuery<InsertUserInput, Int>
     let selectUsers: AnyQuery<(), [User]>
     let selectUserById: AnyQuery<Int, User?>
     let selectUserByIds: AnyQuery<[Int], [User]>
@@ -213,7 +213,7 @@ struct QueriesQueriesNoop: QueriesQueries {
     let selectWithOptionalInterest: AnyQuery<(), [SelectWithOptionalInterestOutput]>
 
     init(
-        insertUser: any InsertUserQuery = Queries.Just(),
+        insertUser: any InsertUserQuery = Queries.Just(0),
         selectUsers: any SelectUsersQuery = Queries.Just(),
         selectUserById: any SelectUserByIdQuery = Queries.Just(),
         selectUserByIds: any SelectUserByIdsQuery = Queries.Just(),
@@ -236,15 +236,15 @@ struct QueriesQueriesNoop: QueriesQueries {
 struct QueriesQueriesImpl: QueriesQueries {
     let connection: any Connection
 
-    var insertUser: DatabaseQuery<InsertUserInput, ()> {
-        DatabaseQuery<InsertUserInput, ()>(
+    var insertUser: DatabaseQuery<InsertUserInput, Int> {
+        DatabaseQuery<InsertUserInput, Int>(
             .write,
             in: connection,
             watchingTables: ["user"]
         ) { input, tx in
             let statement = try Otter.Statement(
                 """
-                INSERT INTO user VALUES (?, ?, ?, ?, ?, ?, ?)
+                INSERT INTO user VALUES (?, ?, ?, ?, ?, ?, ?) RETURNING id
                 """,
                 transaction: tx
             )
@@ -255,7 +255,7 @@ struct QueriesQueriesImpl: QueriesQueries {
             try statement.bind(value: input.favoriteNumber, to: 5)
             try statement.bind(value: input.randomValue, to: 6)
             try statement.bind(value: input.bornOn, to: 7, using: CustomDateDatabaseValueAdapter.self, as: String.self)
-            _ = try statement.step()
+            return try statement.fetchOne()
         }
     }
 
@@ -410,13 +410,13 @@ struct DB: Database{
     }
 }
 
-typealias InsertUserQuery = Query<InsertUserInput, ()>
+typealias InsertUserQuery = Query<InsertUserInput, Int>
 extension Query where Input == InsertUserInput {
     func execute(id: Int, firstName: String, lastName: String, preference: Bool?, favoriteNumber: Int?, randomValue: SQLAny?, bornOn: Date?) async throws -> Output {
         try await execute(with: InsertUserInput(id: id, firstName: firstName, lastName: lastName, preference: preference, favoriteNumber: favoriteNumber, randomValue: randomValue, bornOn: bornOn))
     }
 
-    func execute(id: Int, firstName: String, lastName: String, preference: Bool?, favoriteNumber: Int?, randomValue: SQLAny?, bornOn: Date?, tx: borrowing Transaction) async throws -> Output {
+    func execute(id: Int, firstName: String, lastName: String, preference: Bool?, favoriteNumber: Int?, randomValue: SQLAny?, bornOn: Date?, tx: borrowing Transaction) throws -> Output {
         try execute(with: InsertUserInput(id: id, firstName: firstName, lastName: lastName, preference: preference, favoriteNumber: favoriteNumber, randomValue: randomValue, bornOn: bornOn), tx: tx)
     }
 
@@ -435,7 +435,7 @@ extension Query where Input == SelectUserWithManyInputsInput {
         try await execute(with: SelectUserWithManyInputsInput(id: id, firstName: firstName))
     }
 
-    func execute(id: Int, firstName: String, tx: borrowing Transaction) async throws -> Output {
+    func execute(id: Int, firstName: String, tx: borrowing Transaction) throws -> Output {
         try execute(with: SelectUserWithManyInputsInput(id: id, firstName: firstName), tx: tx)
     }