fix: Ensure accurate app/device info after restart (match Android SDK…

… behavior)

* Store app and device info in session record

This brings the iOS SDK in line with the Android SDK to ensure that session begin and end events always have the same app and device info such as app and iOS versions. Previously, if the app was updated before all sessions were finished, the end session event would have the new app version and not match up with the begin session event. This could also apply to any additional events from that previous session that were waiting to be uploaded.

* Fix thread deadlock race condition in MPApplication

After finally getting it to reproduce reliably, I was able to narrow the problem down to the call to the `badgeNumber` property accessor in `MPApplication`.

The root issue was the fact that the `applicationIconBadgeNumber` property of `UIApplication` must be read from the main thread, so there was a dispatch_sync to the main queue used to read it. However, after moving the timing of that read from the time of event upload to the time of session creation, it could trigger a deadlock if the main thread happened to currently be dispatch_syncing a block to the serial message queue while this was running on the message queue and dispatch_syncing to the main queue.

To address this, I’ve changed the behavior of this property to instead read from user defaults and to update that value when `MPStateMachine` is initialized, as well as when the app enters the background or foreground (also inside `MPStateMachine` for consistency). This removes the need for the dispatch_sync at all as user defaults is thread safe and the updating of the value always happens on the main thread (or is asynced to the main thread if not).

mParticle-Apple-SDK/Data Model/MPSession.h

@@ -15,6 +15,9 @@
 @property (nonatomic, unsafe_unretained, readonly) BOOL persisted;
 @property (nonatomic, strong, readwrite, nonnull) NSNumber *userId;
 @property (nonatomic, strong, readwrite, nonnull) NSString *sessionUserIds;
+@property (nonatomic, strong, readwrite, nullable) NSDictionary<NSString *, id> *appInfo;
+@property (nonatomic, strong, readwrite, nullable) NSDictionary *deviceInfo;
+
 
 - (nonnull instancetype)initWithStartTime:(NSTimeInterval)timestamp userId:(nonnull NSNumber *)userId;
 - (nonnull instancetype)initWithStartTime:(NSTimeInterval)timestamp userId:(nonnull NSNumber *)userId uuid:(nullable NSString *)uuid;
@@ -29,7 +32,10 @@
                              eventCounter:(uint)eventCounter
                               suspendTime:(NSTimeInterval)suspendTime
                                    userId:(nonnull NSNumber *)userId
-                           sessionUserIds:(nonnull NSString *)sessionUserIds __attribute__((objc_designated_initializer));
+                           sessionUserIds:(nonnull NSString *)sessionUserIds
+                                  appInfo:(nullable NSDictionary<NSString *, id> *)appInfo
+                               deviceInfo:(nullable NSDictionary *)deviceInfo
+                            __attribute__((objc_designated_initializer));
 
 - (void)incrementCounter;
 - (void)suspendSession;

mParticle-Apple-SDK/Data Model/MPSession.m

@@ -1,14 +1,29 @@
 #import "MPSession.h"
 #import "MPIConstants.h"
 #import "MPPersistenceController.h"
+#import "MPApplication.h"
+#import "MPDevice.h"
 
 NSString *const sessionUUIDKey = @"sessionId";
 
 @implementation MPSession
 
 - (instancetype)init {
     NSTimeInterval now = [[NSDate date] timeIntervalSince1970];
-    return [self initWithSessionId:0 UUID:[[NSUUID UUID] UUIDString] backgroundTime:0.0 startTime:now endTime:now attributes:nil numberOfInterruptions:0 eventCounter:0 suspendTime:0 userId:[MPPersistenceController mpId] sessionUserIds:[[MPPersistenceController mpId] stringValue]];
+    NSNumber *mpId = [MPPersistenceController mpId];
+    return [self initWithSessionId:0
+                              UUID:[[NSUUID UUID] UUIDString]
+                    backgroundTime:0.0
+                         startTime:now
+                           endTime:now
+                        attributes:nil
+             numberOfInterruptions:0
+                      eventCounter:0
+                       suspendTime:0
+                            userId:mpId
+                    sessionUserIds:[mpId stringValue]
+                           appInfo:nil
+                        deviceInfo:nil];
 }
 
 - (instancetype)initWithStartTime:(NSTimeInterval)timestamp userId:(NSNumber *)userId {
@@ -19,7 +34,19 @@ - (instancetype)initWithStartTime:(NSTimeInterval)timestamp userId:(NSNumber *)u
 
 - (instancetype)initWithStartTime:(NSTimeInterval)timestamp userId:(NSNumber *)userId uuid:(NSString *)uuid {
     NSString *uuidString = uuid ?: [[NSUUID UUID] UUIDString];
-    self = [self initWithSessionId:0 UUID:uuidString backgroundTime:0.0 startTime:timestamp endTime:timestamp attributes:nil numberOfInterruptions:0 eventCounter:0 suspendTime:0 userId:userId sessionUserIds:[userId stringValue]];
+    self = [self initWithSessionId:0
+                              UUID:uuidString
+                    backgroundTime:0.0
+                         startTime:timestamp
+                           endTime:timestamp
+                        attributes:nil
+             numberOfInterruptions:0
+                      eventCounter:0
+                       suspendTime:0
+                            userId:userId
+                    sessionUserIds:[userId stringValue]
+                           appInfo:nil
+                        deviceInfo:nil];
 
     return self;
 }
@@ -35,6 +62,8 @@ - (instancetype)initWithSessionId:(int64_t)sessionId
                       suspendTime:(NSTimeInterval)suspendTime
                            userId:(NSNumber *)userId
                    sessionUserIds:(NSString *)sessionUserIds
+                          appInfo:(nullable NSDictionary<NSString *,id> *)appInfo
+                       deviceInfo:(nullable NSDictionary *)deviceInfo
 {
     self = [super init];
     if (!self) {
@@ -52,6 +81,8 @@ - (instancetype)initWithSessionId:(int64_t)sessionId
     _numberOfInterruptions = numberOfInterruptions;
     _suspendTime = suspendTime;
     _sessionUserIds = sessionUserIds;
+    _appInfo = appInfo;
+    _deviceInfo = deviceInfo;
 
     _attributesDictionary = attributesDictionary != nil ? attributesDictionary : [[NSMutableDictionary alloc] init];
 
@@ -88,7 +119,9 @@ - (id)copyWithZone:(NSZone *)zone {
                                                     eventCounter:_eventCounter
                                                      suspendTime:_suspendTime
                                                           userId:_userId
-                                                  sessionUserIds:_sessionUserIds];
+                                                  sessionUserIds:_sessionUserIds
+                                                         appInfo:_appInfo
+                                                      deviceInfo:_deviceInfo];
 
     return copyObject;
 }

mParticle-Apple-SDK/MPBackendController.mm

@@ -34,6 +34,7 @@
 #import "MPArchivist.h"
 #import "MPListenerController.h"
 #import "MParticleWebView.h"
+#import "MPDevice.h"
 
 #if TARGET_OS_IOS == 1
 #import "MPLocationManager.h"
@@ -1146,11 +1147,20 @@ - (void)beginSessionWithIsManual:(BOOL)isManual date:(NSDate *)date {
         MPStateMachine *stateMachine = [MParticle sharedInstance].stateMachine;
         MPPersistenceController *persistence = [MParticle sharedInstance].persistenceController;
 
+        NSNumber *mpId = [MPPersistenceController mpId];
         date = date ?: [NSDate date];
         if (tempSession) {
-            self.session = [[MPSession alloc] initWithStartTime:[date timeIntervalSince1970] userId:[MPPersistenceController mpId] uuid:tempSession.UUID];
+            self.session = [[MPSession alloc] initWithStartTime:[date timeIntervalSince1970] userId:mpId uuid:tempSession.UUID];
         } else {
-            self.session = [[MPSession alloc] initWithStartTime:[date timeIntervalSince1970] userId:[MPPersistenceController mpId]];
+            self.session = [[MPSession alloc] initWithStartTime:[date timeIntervalSince1970] userId:mpId];
+        }
+
+        // Set the app and device info dicts if they weren't already created
+        if (!_session.appInfo) {
+            _session.appInfo = [[[MPApplication alloc] init] dictionaryRepresentation];
+        }
+        if (!_session.deviceInfo) {
+            _session.deviceInfo = [[[MPDevice alloc] init] dictionaryRepresentationWithMpid:mpId];
         }
 
         [persistence saveSession:_session];

mParticle-Apple-SDK/Persistence/MPDatabaseMigrationController.m

@@ -107,11 +107,13 @@ - (void)migrateSessionsFromDatabase:(sqlite3 *)oldDatabase version:(NSNumber *)o
         selectStatement = "SELECT uuid, start_time, end_time, attributes_data, session_number, background_time, number_interruptions, event_count, suspend_time FROM sessions ORDER BY _id";
     } else if (oldVersionValue < 26) {
         selectStatement = "SELECT uuid, start_time, end_time, attributes_data, session_number, background_time, number_interruptions, event_count, suspend_time, length FROM sessions ORDER BY _id";
-    } else {
+    } else if (oldVersionValue < 30) {
         selectStatement = "SELECT uuid, start_time, end_time, attributes_data, session_number, background_time, number_interruptions, event_count, suspend_time, length, mpid, session_user_ids FROM sessions ORDER BY _id";
+    } else {
+        selectStatement = "SELECT uuid, start_time, end_time, attributes_data, session_number, background_time, number_interruptions, event_count, suspend_time, length, mpid, session_user_ids, app_info, device_info FROM sessions ORDER BY _id";
     }
 
-    insertStatement = "INSERT INTO sessions (uuid, background_time, start_time, end_time, attributes_data, session_number, number_interruptions, event_count, suspend_time, length, mpid, session_user_ids) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
+    insertStatement = "INSERT INTO sessions (uuid, background_time, start_time, end_time, attributes_data, session_number, number_interruptions, event_count, suspend_time, length, mpid, session_user_ids, app_info, device_info) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)";
 
     sqlite3_prepare_v2(oldDatabase, selectStatement, -1, &selectStatementHandle, NULL);
     sqlite3_prepare_v2(newDatabase, insertStatement, -1, &insertStatementHandle, NULL);
@@ -168,7 +170,16 @@ - (void)migrateSessionsFromDatabase:(sqlite3 *)oldDatabase version:(NSNumber *)o
         sqlite3_bind_double(insertStatementHandle, 10, length); // length
         sqlite3_bind_int64(insertStatementHandle, 11, [mpId longLongValue]); // mpid
         sqlite3_bind_text(insertStatementHandle, 12, (const char *)[mpId stringValue].UTF8String, -1, SQLITE_TRANSIENT); // session_user_ids
-
+
+        if (oldVersionValue > 29) {
+            sqlite3_bind_blob(insertStatementHandle, 13, sqlite3_column_blob(selectStatementHandle, 12), sqlite3_column_bytes(selectStatementHandle, 12), SQLITE_TRANSIENT);
+            sqlite3_bind_blob(insertStatementHandle, 14, sqlite3_column_blob(selectStatementHandle, 13), sqlite3_column_bytes(selectStatementHandle, 13), SQLITE_TRANSIENT);
+        } else {
+            // Columns don't exist in old table, so just explicitly bind null
+            sqlite3_bind_null(insertStatementHandle, 13);
+            sqlite3_bind_null(insertStatementHandle, 14);
+        }
+
         sqlite3_step(insertStatementHandle);
         sqlite3_reset(insertStatementHandle);
     }

mParticle-Apple-SDK/Persistence/MPPersistenceController.h

@@ -70,6 +70,7 @@
 - (void)saveUpload:(nonnull MPUpload *)upload;
 - (void)updateConsumerInfo:(nonnull MPConsumerInfo *)consumerInfo;
 - (void)updateSession:(nonnull MPSession *)session;
+- (nonnull NSDictionary<NSString *, NSDictionary *> *)appAndDeviceInfoForSessionId:(nonnull NSNumber *)sessionId;
 
 @end