Update connector for better Sendable support

Author: stevensJourney

Demo/PowerSyncExample/PowerSync/SupabaseConnector.swift

@@ -38,7 +38,7 @@ private enum PostgresFatalCodes {
 }
 
 @Observable
-class SupabaseConnector: PowerSyncBackendConnector {
+final class SupabaseConnector: PowerSyncBackendConnectorProtocol {
     let powerSyncEndpoint: String = Secrets.powerSyncEndpoint
     let client: SupabaseClient = .init(
         supabaseURL: Secrets.supabaseURL,
@@ -50,8 +50,7 @@ class SupabaseConnector: PowerSyncBackendConnector {
     @ObservationIgnored
     private var observeAuthStateChangesTask: Task<Void, Error>?
 
-    override init() {
-        super.init()
+    init() {
         session = client.auth.currentSession
         observeAuthStateChangesTask = Task { [weak self] in
             guard let self = self else { return }
@@ -80,7 +79,7 @@ class SupabaseConnector: PowerSyncBackendConnector {
         return client.storage.from(bucket)       
     }
 
-    override func fetchCredentials() async throws -> PowerSyncCredentials? {
+    func fetchCredentials() async throws -> PowerSyncCredentials? {
         session = try await client.auth.session
 
         if session == nil {
@@ -92,7 +91,7 @@ class SupabaseConnector: PowerSyncBackendConnector {
         return PowerSyncCredentials(endpoint: powerSyncEndpoint, token: token)
     }
 
-    override func uploadData(database: PowerSyncDatabaseProtocol) async throws {
+    func uploadData(database: PowerSyncDatabaseProtocol) async throws {
         guard let transaction = try await database.getNextCrudTransaction() else { return }
 
         var lastEntry: CrudEntry?

Demo/PowerSyncExample/PowerSync/SystemManager.swift

@@ -13,7 +13,6 @@ func getAttachmentsDirectoryPath() throws -> String {
 
 let logTag = "SystemManager"
 
-@MainActor
 @Observable
 class SystemManager {
     let connector = SupabaseConnector()
@@ -242,7 +241,7 @@ class SystemManager {
         }
     }
 
-    private nonisolated func deleteTodoInTX(id: String, tx: ConnectionContext) throws {
+    private func deleteTodoInTX(id: String, tx: ConnectionContext) throws {
         _ = try tx.execute(
             sql: "DELETE FROM \(TODOS_TABLE) WHERE id = ?",
             parameters: [id]

Sources/PowerSync/Kotlin/KotlinPowerSyncDatabaseImpl.swift

@@ -45,7 +45,7 @@ final class KotlinPowerSyncDatabaseImpl: PowerSyncDatabaseProtocol,
     }
 
     func connect(
-        connector: PowerSyncBackendConnector,
+        connector: PowerSyncBackendConnectorProtocol,
         options: ConnectOptions?
     ) async throws {
         let connectorAdapter = PowerSyncBackendConnectorAdapter(

Sources/PowerSync/Kotlin/PowerSyncBackendConnectorAdapter.swift

@@ -4,12 +4,12 @@ final class PowerSyncBackendConnectorAdapter: KotlinPowerSyncBackendConnector,
     // We need to declare this since we declared KotlinPowerSyncBackendConnector as @unchecked Sendable
     @unchecked Sendable
 {
-    let swiftBackendConnector: PowerSyncBackendConnector
+    let swiftBackendConnector: PowerSyncBackendConnectorProtocol
     let db: any PowerSyncDatabaseProtocol
     let logTag = "PowerSyncBackendConnector"
 
     init(
-        swiftBackendConnector: PowerSyncBackendConnector,
+        swiftBackendConnector: PowerSyncBackendConnectorProtocol,
         db: any PowerSyncDatabaseProtocol
     ) {
         self.swiftBackendConnector = swiftBackendConnector

Sources/PowerSync/Protocol/PowerSyncBackendConnector.swift

@@ -1,3 +1,10 @@
+
+/// Implement this to connect an app backend.
+///
+/// The connector is responsible for:
+/// 1. Creating credentials for connecting to the PowerSync service.
+/// 2. Applying local changes against the backend application server.
+///
 public protocol PowerSyncBackendConnectorProtocol: Sendable {
     ///
     /// Get credentials for PowerSync.
@@ -22,14 +29,11 @@ public protocol PowerSyncBackendConnectorProtocol: Sendable {
     func uploadData(database: PowerSyncDatabaseProtocol) async throws
 }
 
-/// Implement this to connect an app backend.
-///
-/// The connector is responsible for:
-/// 1. Creating credentials for connecting to the PowerSync service.
-/// 2. Applying local changes against the backend application server.
-///
-@MainActor // This class is non-final, we can use actor isolation to make it Sendable
-open class PowerSyncBackendConnector: PowerSyncBackendConnectorProtocol {
+@available(*, deprecated, message: "PowerSyncBackendConnector is deprecated. Please implement PowerSyncBackendConnectorProtocol directly in your own class.")
+open class PowerSyncBackendConnector: PowerSyncBackendConnectorProtocol,
+    // This class is non-final, implementations should strictly conform to Sendable
+    @unchecked Sendable
+{
     public init() {}
 
     open func fetchCredentials() async throws -> PowerSyncCredentials? {

Sources/PowerSync/Protocol/PowerSyncDatabaseProtocol.swift

@@ -169,7 +169,7 @@ public protocol PowerSyncDatabaseProtocol: Queries, Sendable {
     ///
     /// - Throws: An error if the connection fails or if the database is not properly configured.
     func connect(
-        connector: PowerSyncBackendConnector,
+        connector: PowerSyncBackendConnectorProtocol,
         options: ConnectOptions?
     ) async throws