Proper RSH8b and RSH3g2a behavior.

Source/ARTLocalDevice.m

@@ -46,17 +46,16 @@ @interface ARTLocalDevice ()
 
 @implementation ARTLocalDevice
 
-- (instancetype)initWithClientId:(NSString *)clientId storage:(id<ARTDeviceStorage>)storage logger:(nullable ARTInternalLog *)logger {
+- (instancetype)initWithStorage:(id<ARTDeviceStorage>)storage logger:(nullable ARTInternalLog *)logger {
     if (self = [super init]) {
-        self.clientId = clientId;
         self.storage = storage;
         _logger = logger;
     }
     return self;
 }
 
-+ (ARTLocalDevice *)load:(NSString *)clientId storage:(id<ARTDeviceStorage>)storage logger:(nullable ARTInternalLog *)logger {
-    ARTLocalDevice *device = [[ARTLocalDevice alloc] initWithClientId:clientId storage:storage logger:logger];
++ (instancetype)deviceWithStorage:(id<ARTDeviceStorage>)storage logger:(nullable ARTInternalLog *)logger {
+    ARTLocalDevice *device = [[ARTLocalDevice alloc] initWithStorage:storage logger:logger];
     device.platform = ARTDevicePlatform;
     #if TARGET_OS_IOS
     switch ([[UIDevice currentDevice] userInterfaceIdiom]) {
@@ -72,24 +71,18 @@ + (ARTLocalDevice *)load:(NSString *)clientId storage:(id<ARTDeviceStorage>)stor
     #endif
     device.push.recipient[@"transportType"] = ARTDevicePushTransportType;
 
-    NSString *deviceId = [storage objectForKey:ARTDeviceIdKey];
+    NSString *deviceId = [storage objectForKey:ARTDeviceIdKey] ?: @""; // PCD2, not nullable
     NSString *deviceSecret = deviceId == nil ? nil : [storage secretForDevice:deviceId];
 
-    if (deviceId == nil || deviceSecret == nil) { // generate both at the same time
-        deviceId = [self generateId];
-        deviceSecret = [self generateSecret];
-
-        [storage setObject:deviceId forKey:ARTDeviceIdKey];
-        [storage setSecret:deviceSecret forDevice:deviceId];
-    }
-
     device.id = deviceId;
     device.secret = deviceSecret;
 
     id identityTokenDetailsInfo = [storage objectForKey:ARTDeviceIdentityTokenKey];
     ARTDeviceIdentityTokenDetails *identityTokenDetails = [ARTDeviceIdentityTokenDetails unarchive:identityTokenDetailsInfo withLogger:logger];
     device->_identityTokenDetails = identityTokenDetails;
 
+    device.clientId = identityTokenDetails.clientId;
+
     NSArray *supportedTokenTypes = @[
         ARTAPNSDeviceDefaultTokenType,
         ARTAPNSDeviceLocationTokenType
@@ -102,6 +95,33 @@ + (ARTLocalDevice *)load:(NSString *)clientId storage:(id<ARTDeviceStorage>)stor
     return device;
 }
 
+- (BOOL)setupDetailsWithClientId:(NSString *)clientId {
+    NSString *deviceId = self.id;
+    NSString *deviceSecret = self.secret;
+
+    if ([deviceId isEqualToString:@""] || deviceSecret == nil) { // generate both at the same time
+        deviceId = [self.class generateId];
+        deviceSecret = [self.class generateSecret];
+
+        [_storage setObject:deviceId forKey:ARTDeviceIdKey];
+        [_storage setSecret:deviceSecret forDevice:deviceId];
+    }
+
+    self.id = deviceId;
+    self.secret = deviceSecret;
+
+    NSString *localClientId = self.clientId;
+
+    if (localClientId && clientId && ![localClientId isEqualToString:clientId]) {
+        ARTLogError(self.logger, @"ARTLocalDevice: `clientId`s don't match: %@ vs %@.", clientId, localClientId);
+        return NO;
+    }
+    if (clientId) {
+        self.clientId = clientId;
+    }
+    return YES;
+}
+
 + (NSString *)generateId {
     return [NSUUID new].UUIDString;
 }

Source/ARTPushActivationState.m

@@ -117,6 +117,9 @@ - (ARTPushActivationState *)transition:(ARTPushActivationEvent *)event {
     }
     else if ([event isKindOfClass:[ARTPushActivationEventCalledActivate class]]) {
         [self.machine registerForAPNS];
+#if TARGET_OS_IOS
+        [self.machine.rest setupLocalDevice];
+#endif
         return validateAndSync(self.machine, event, self.logger);
     }
     return nil;

Source/ARTRest.m

@@ -744,10 +744,9 @@ - (ARTLocalDevice *)device {
 }
 
 - (ARTLocalDevice *)device_nosync {
-    NSString *clientId = self.auth.clientId_nosync;
     __block ARTLocalDevice *ret;
-    dispatch_sync(ARTRestInternal.deviceAccessQueue, ^{
-        ret = [self deviceWithClientId_onlyCallOnDeviceAccessQueue:clientId];
+    dispatch_sync([ARTRestInternal deviceAccessQueue], ^{
+        ret = [self sharedDevice_onlyCallOnDeviceAccessQueue];
     });
     return ret;
 }
@@ -765,7 +764,7 @@ + (dispatch_queue_t)deviceAccessQueue {
 
 static BOOL sharedDeviceNeedsLoading_onlyAccessOnDeviceAccessQueue = YES;
 
-- (ARTLocalDevice *)deviceWithClientId_onlyCallOnDeviceAccessQueue:(NSString *)clientId {
+- (ARTLocalDevice *)sharedDevice_onlyCallOnDeviceAccessQueue {
     // The device is shared in a static variable because it's a reflection
     // of what's persisted. Having a device instance per ARTRest instance
     // could leave some instances in a stale state, if, through another
@@ -776,12 +775,20 @@ - (ARTLocalDevice *)deviceWithClientId_onlyCallOnDeviceAccessQueue:(NSString *)c
 
     static id device;
     if (sharedDeviceNeedsLoading_onlyAccessOnDeviceAccessQueue) {
-        device = [ARTLocalDevice load:clientId storage:self.storage logger:self.logger];
+        device = [ARTLocalDevice deviceWithStorage:self.storage logger:self.logger];
         sharedDeviceNeedsLoading_onlyAccessOnDeviceAccessQueue = NO;
     }
     return device;
 }
 
+- (void)setupLocalDevice {
+    ARTLocalDevice *device = [self device_nosync];
+    NSString *clientId = self.auth.clientId_nosync;
+    dispatch_sync([ARTRestInternal deviceAccessQueue], ^{
+        [device setupDetailsWithClientId:clientId];
+    });
+}
+
 - (void)resetDeviceSingleton {
     dispatch_sync([ARTRestInternal deviceAccessQueue], ^{
         sharedDeviceNeedsLoading_onlyAccessOnDeviceAccessQueue = YES;

Source/PrivateHeaders/Ably/ARTLocalDevice+Private.h

@@ -19,13 +19,14 @@ NSString* ARTAPNSDeviceTokenKeyOfType(NSString * _Nullable tokenType);
 
 @property (nonatomic) id<ARTDeviceStorage> storage;
 
-+ (ARTLocalDevice *)load:(NSString *)clientId storage:(id<ARTDeviceStorage>)storage logger:(nullable ARTInternalLog *)logger;
++ (instancetype)deviceWithStorage:(id<ARTDeviceStorage>)storage logger:(nullable ARTInternalLog *)logger;
 - (nullable NSString *)apnsDeviceToken;
 - (void)setAndPersistAPNSDeviceToken:(nullable NSString *)deviceToken tokenType:(NSString *)tokenType;
 - (void)setAndPersistAPNSDeviceToken:(nullable NSString *)deviceToken;
 - (void)setAndPersistIdentityTokenDetails:(nullable ARTDeviceIdentityTokenDetails *)tokenDetails;
 - (BOOL)isRegistered;
 - (void)clearIdentityTokenDetailsAndClientId;
+- (BOOL)setupDetailsWithClientId:(nullable NSString *)clientId;
 
 + (NSString *)generateId;
 + (NSString *)generateSecret;

Source/PrivateHeaders/Ably/ARTRest+Private.h

@@ -76,6 +76,7 @@ NS_ASSUME_NONNULL_BEGIN
 - (nullable NSObject<ARTCancellable> *)internetIsUp:(void (^)(BOOL isUp))cb;
 
 #if TARGET_OS_IOS
+- (void)setupLocalDevice;
 // This is only intended to be called from test code.
 - (void)resetDeviceSingleton;