Update Kotlin SDK and core extension

.github/workflows/build_and_test.yaml

@@ -14,25 +14,13 @@ jobs:
         uses: maxim-lobanov/setup-xcode@v1
         with:
           xcode-version: latest-stable
-      - name: Build and Test
+
+      - name: Test on iOS simulator
         run: |
           xcodebuild test -scheme PowerSync-Package -destination "platform=iOS Simulator,name=iPhone 16"
-          xcodebuild test -scheme PowerSync-Package -destination "platform=macOS,arch=arm64,name=My Mac"
-          xcodebuild test -scheme PowerSync-Package -destination "platform=watchOS Simulator,arch=arm64,name=Apple Watch Ultra 2 (49mm)"
-
-  buildSwift6:
-    name: Build and test with Swift 6
-    runs-on: macos-latest
-    steps:
-      - uses: actions/checkout@v4
-      - name: Set up XCode
-        uses: maxim-lobanov/setup-xcode@v1
-        with:
-          xcode-version: latest-stable
-      - name: Use Swift 6
+      - name: Test on macOS
         run: |
-          sed -i '' 's|^// swift-tools-version:.*$|// swift-tools-version:6.1|' Package.swift
-      - name: Build and Test
+          xcodebuild test -scheme PowerSync-Package -destination "platform=macOS,arch=arm64,name=My Mac"
+      - name: Test on watchOS simulator
         run: |
-          swift build -Xswiftc -strict-concurrency=complete
-          swift test -Xswiftc -strict-concurrency=complete
+          xcodebuild test -scheme PowerSync-Package -destination "platform=watchOS Simulator,arch=arm64,name=Apple Watch Ultra 2 (49mm)"

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.7
+// swift-tools-version: 6.1
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
@@ -18,22 +18,43 @@ let localCoreExtension: String? = nil
 // a binary target.
 // With a local SDK, we point to a `Package.swift` within the Kotlin SDK containing a target pointing
 // towards a local framework build
-var conditionalDependencies: [Package.Dependency] = []
+var conditionalDependencies: [Package.Dependency] = [
+    .package(
+        url: "https://github.com/sbooth/CSQLite.git",
+        from: "3.50.4",
+        traits: [
+            .defaults,
+            // CSQLite uses THREADSAFE=0 by default, which breaks PowerSync because we're using SQLite on
+            // multiple threads (it can lead to race conditions when closing connections sharing resources
+            // like shared memory, causing crashes).
+            // THREADSAFE=2 overrides the default, and is safe to use as long as a single SQLite connection
+            // is not shared between threads.
+            // TODO: Technically, we should not use .defaults because there's a logical conflict between
+            // the threadsafe options. Instead, we should spell out all defaults again and remove that
+            // thread-safety option.
+            // However, despite the docs explicitly saying something else, it looks like there's no way to
+            // disable default traits anyway (XCode compiles sqlite3.c with the default option even without
+            // .defaults being included here).
+            "THREADSAFE_2",
+            "ENABLE_SESSION"
+        ]
+    )
+]
 var conditionalTargets: [Target] = []
 var kotlinTargetDependency = Target.Dependency.target(name: "PowerSyncKotlin")
 
 if let kotlinSdkPath = localKotlinSdkOverride {
     // We can't depend on local XCFrameworks outside of this project's root, so there's a Package.swift
     // in the PowerSyncKotlin project pointing towards a local build.
-    conditionalDependencies.append(.package(path: "\(kotlinSdkPath)/PowerSyncKotlin"))
+    conditionalDependencies.append(.package(path: "\(kotlinSdkPath)/internal/PowerSyncKotlin"))
 
     kotlinTargetDependency = .product(name: "PowerSyncKotlin", package: "PowerSyncKotlin")
 } else {
     // Not using a local build, so download from releases
     conditionalTargets.append(.binaryTarget(
         name: "PowerSyncKotlin",
-        url: "https://github.com/powersync-ja/powersync-kotlin/releases/download/v1.7.0/PowersyncKotlinRelease.zip",
-        checksum: "836ac106c26a184c10373c862745d9af195737ad01505bb965f197797aa88535"
+        url: "https://github.com/powersync-ja/powersync-kotlin/releases/download/v1.8.0/PowersyncKotlinRelease.zip",
+        checksum: "31ac7c5e11d747e11bceb0b34f30438d37033e700c621b0a468aa308d887587f"
     ))
 }
 
@@ -45,7 +66,7 @@ if let corePath = localCoreExtension {
     // Not using a local build, so download from releases
     conditionalDependencies.append(.package(
         url: "https://github.com/powersync-ja/powersync-sqlite-core-swift.git",
-        exact: "0.4.6"
+        exact: "0.4.8"
     ))
 }
 
@@ -81,7 +102,8 @@ let package = Package(
             name: packageName,
             dependencies: [
                 kotlinTargetDependency,
-                .product(name: "PowerSyncSQLiteCore", package: corePackageName)
+                .product(name: "PowerSyncSQLiteCore", package: corePackageName),
+                .product(name: "CSQLite", package: "CSQLite")
             ]
         ),
         .testTarget(

Sources/PowerSync/Kotlin/KotlinAdapter.swift

@@ -49,7 +49,8 @@ enum KotlinAdapter {
             return PowerSyncKotlin.RawTable(
                 name: table.name,
                 put: translateStatement(table.put),
-                delete: translateStatement(table.delete)
+                delete: translateStatement(table.delete),
+                clear: table.clear,
             );
         }
 

Sources/PowerSync/Kotlin/KotlinPowerSyncDatabaseImpl.swift

@@ -1,5 +1,6 @@
 import Foundation
 import PowerSyncKotlin
+import CSQLite
 
 final class KotlinPowerSyncDatabaseImpl: PowerSyncDatabaseProtocol,
     // `PowerSyncKotlin.PowerSyncDatabase` cannot be marked as Sendable
@@ -15,7 +16,12 @@ final class KotlinPowerSyncDatabaseImpl: PowerSyncDatabaseProtocol,
         dbFilename: String,
         logger: DatabaseLogger
     ) {
-        let factory = PowerSyncKotlin.DatabaseDriverFactory()
+        let rc = sqlite3_initialize();
+        if (rc != 0) {
+            fatalError("Call to sqlite3_initialize() failed with \(rc)")
+        }
+
+        let factory = sqlite3DatabaseFactory(initialStatements: [])
         kotlinDatabase = PowerSyncDatabase(
             factory: factory,
             schema: KotlinAdapter.Schema.toKotlin(schema),
@@ -87,9 +93,10 @@ final class KotlinPowerSyncDatabaseImpl: PowerSyncDatabaseProtocol,
         try await kotlinDatabase.disconnect()
     }
 
-    func disconnectAndClear(clearLocal: Bool = true) async throws {
+    func disconnectAndClear(clearLocal: Bool, soft: Bool) async throws {
         try await kotlinDatabase.disconnectAndClear(
-            clearLocal: clearLocal
+            clearLocal: clearLocal,
+            soft: soft
         )
     }
 

Sources/PowerSync/Protocol/PowerSyncDatabaseProtocol.swift

@@ -216,12 +216,20 @@ public protocol PowerSyncDatabaseProtocol: Queries, Sendable {
     func disconnect() async throws
 
     /// Disconnect and clear the database.
-    /// Use this when logging out.
-    /// The database can still be queried after this is called, but the tables
-    /// would be empty.
     ///
-    /// - Parameter clearLocal: Set to false to preserve data in local-only tables. Defaults to `true`.
-    func disconnectAndClear(clearLocal: Bool) async throws
+    /// Clearing the database is useful when a user logs out, to ensure another user logging in later would not see
+    /// previous data.
+    ///
+    /// The database can still be queried after this is called, but the tables would be empty.
+    ///
+    /// To perserve data in local-only tables, set `clearLocal` to `false`.
+    ///
+    /// A `soft` clear deletes publicly visible data, but keeps internal copies of data synced in the database. This
+    /// usually means that if the same user logs out and back in again, the first sync is very fast because all internal
+    /// data is still available. When a different user logs in, no old data would be visible at any point.
+    /// Using soft clears is recommended where it's not a security issue that old data could be reconstructed from
+    /// the database.
+    func disconnectAndClear(clearLocal: Bool, soft: Bool) async throws
 
     /// Close the database, releasing resources.
     /// Also disconnects any active connection.
@@ -290,7 +298,15 @@ public extension PowerSyncDatabaseProtocol {
     }
 
     func disconnectAndClear() async throws {
-        try await disconnectAndClear(clearLocal: true)
+        try await disconnectAndClear(clearLocal: true, soft: false)
+    }
+
+    func disconnectAndClear(clearLocal: Bool) async throws {
+        try await disconnectAndClear(clearLocal: clearLocal, soft: false)
+    }
+
+    func disconnectAndClear(soft: Bool) async throws {
+        try await disconnectAndClear(clearLocal: true, soft: soft)
     }
 
     func getCrudBatch(limit: Int32 = 100) async throws -> CrudBatch? {

Sources/PowerSync/Protocol/Schema/RawTable.swift

@@ -24,11 +24,15 @@ public struct RawTable: BaseTableProtocol {
 
     /// The statement to run when the sync client has to delete a row.
     public let delete: PendingStatement
+
+    /// An optional statement to run when the database is cleared.
+    public let clear: String?
 
-    public init(name: String, put: PendingStatement, delete: PendingStatement) {
+    public init(name: String, put: PendingStatement, delete: PendingStatement, clear: String? = nil) {
         self.name = name
         self.put = put
         self.delete = delete
+        self.clear = clear
     }
 }
 

Tests/PowerSyncTests/CrudTests.swift

@@ -238,4 +238,19 @@ final class CrudTests: XCTestCase {
         let finalTx = try await database.getNextCrudTransaction()
         XCTAssertEqual(finalTx!.crud.count, 15)
     }
+
+    func testSoftClear() async throws {
+        try await database.execute(sql: "INSERT INTO users (id, name) VALUES (uuid(), ?)", parameters: ["test"]);
+        try await database.execute(sql: "INSERT INTO ps_buckets (name, last_applied_op) VALUES (?, ?)", parameters: ["bkt", 10])
+
+        // Doing a soft-clear should delete data but keep the bucket around.
+        try await database.disconnectAndClear(soft: true)
+        let entries = try await database.getAll("SELECT name FROM ps_buckets", mapper: { cursor in try cursor.getString(index: 0) })
+        XCTAssertEqual(entries.count, 1)
+
+        // Doing a default clear also deletes buckets.
+        try await database.disconnectAndClear();
+        let newEntries = try await database.getAll("SELECT name FROM ps_buckets", mapper: { cursor in try cursor.getString(index: 0) })
+        XCTAssertEqual(newEntries.count, 0)
+    }
 }