Improve TestFlight detection with StoreKit 2 support

Sources/TelemetryDeck/Signals/Signal+Helpers.swift

@@ -11,7 +11,54 @@ import Foundation
     import TVUIKit
 #endif
 
+#if canImport(StoreKit)
+    import StoreKit
+#endif
+
 extension DefaultSignalPayload {
+    /// Cached TestFlight detection from StoreKit 2 (true=TestFlight, false=AppStore, nil=unknown).
+    private nonisolated(unsafe) static var cachedIsTestFlight: Bool?
+
+    /// Initializes environment detection (StoreKit 2 on iOS 16+, receipt-based fallback on older OS).
+    @available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+    static func initializeEnvironmentDetection() async {
+        // Use StoreKit 2 on iOS 16+ for most reliable detection
+        #if canImport(StoreKit)
+            if #available(iOS 16.0, macOS 13.0, tvOS 16.0, watchOS 9.0, *) {
+                do {
+                    let transaction = try await AppTransaction.shared
+
+                    switch transaction {
+                    case let .verified(appTransaction):
+                        // Check the environment property
+                        Self.cachedIsTestFlight = appTransaction.environment == .sandbox
+                        return
+                    case .unverified:
+                        // If verification fails, fall back to receipt-based detection
+                        Self.cachedIsTestFlight = Self.isTestFlightViaReceipt()
+                        return
+                    }
+                } catch {
+                    // If AppTransaction fails, fall back to receipt-based detection
+                    Self.cachedIsTestFlight = Self.isTestFlightViaReceipt()
+                    return
+                }
+            }
+        #endif
+
+        // For iOS < 16, use receipt-based detection
+        Self.cachedIsTestFlight = isTestFlightViaReceipt()
+    }
+
+    /// Receipt-based TestFlight detection fallback for iOS < 16 or when StoreKit 2 is unavailable.
+    private static func isTestFlightViaReceipt() -> Bool {
+        guard let receiptURL = Bundle.main.appStoreReceiptURL else {
+            return false
+        }
+        // TestFlight builds have "sandboxReceipt" while App Store builds have "receipt"
+        return receiptURL.lastPathComponent == "sandboxReceipt"
+    }
+
     static var calendarParameters: [String: String] {
         let calendar = Calendar(identifier: .gregorian)
         let nowDate = Date()
@@ -99,13 +146,32 @@ extension DefaultSignalPayload {
         #endif
     }
 
+    /// Detects if the app is running in a TestFlight environment.
+    ///
+    /// Uses StoreKit 2's `AppTransaction.shared.environment` on iOS 16+ for reliable detection,
+    /// falling back to receipt-based detection (`sandboxReceipt` vs `receipt`) on earlier OS versions.
+    ///
+    /// The environment is detected asynchronously during `TelemetryDeck.initialize()` and cached
+    /// for fast synchronous access throughout the app session.
+    ///
+    /// - Returns: `true` if running in TestFlight, `false` otherwise
     static var isTestFlight: Bool {
-        guard !isDebug, let path = Bundle.main.appStoreReceiptURL?.path else {
+        #if DEBUG
             return false
-        }
-        return path.contains("sandboxReceipt")
+        #elseif targetEnvironment(simulator)
+            return false
+        #else
+            // Use cached value if available, otherwise use receipt-based fallback
+            return cachedIsTestFlight ?? isTestFlightViaReceipt()
+        #endif
     }
 
+    /// Detects if the app is running in an App Store production environment.
+    ///
+    /// Uses the same detection strategy as `isTestFlight` (see its documentation for details).
+    /// Returns `true` for App Store builds, `false` for debug, simulator, and TestFlight builds.
+    ///
+    /// - Returns: `true` if running in App Store production, `false` otherwise
     static var isAppStore: Bool {
         #if DEBUG
             return false
@@ -114,7 +180,11 @@ extension DefaultSignalPayload {
         #elseif targetEnvironment(simulator)
             return false
         #else
-            return !isSimulatorOrTestFlight
+            // Use cached value if available, otherwise use receipt-based fallback
+            if let isTestFlight = cachedIsTestFlight {
+                return !isTestFlight
+            }
+            return !Self.isTestFlightViaReceipt()
         #endif
     }
 

Sources/TelemetryDeck/TelemetryDeck.swift

@@ -22,6 +22,15 @@ public enum TelemetryDeck {
     /// For example, you might want to call this in your `init` method of your app's `@main` entry point.
     public static func initialize(config: Config) {
         TelemetryManager.initializedTelemetryManager = TelemetryManager(configuration: config)
+
+        // Initialize environment detection asynchronously
+        // This will use StoreKit 2 on iOS 16+ or fallback to receipt-based detection
+        if #available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *) {
+            Task {
+                await DefaultSignalPayload.initializeEnvironmentDetection()
+            }
+        }
+        // On older OS versions, the fallback method will be used on first access
     }
 
     /// Sends a telemetry signal with optional parameters to TelemetryDeck.