We can't hold onto managed objects in our temporary objects because they can disappear from under us, so do the lookup when we propagate values

Limelight/Database/DataManager.h

@@ -25,4 +25,7 @@
 - (void) updateUniqueId:(NSString*)uniqueId;
 - (NSString*) getUniqueId;
 
+// Don't call this outside of database code
+- (App*) getAppForTemporaryApp:(TemporaryApp*)tempApp;
+
 @end

Limelight/Database/DataManager.m

@@ -61,13 +61,14 @@
 - (void) updateHost:(TemporaryHost *)host {
     [_managedObjectContext performBlockAndWait:^{
         // Add a new persistent managed object if one doesn't exist
-        if (host.parent == nil) {
+        Host* parent = [self getHostForTemporaryHost:host];
+        if (parent == nil) {
             NSEntityDescription* entity = [NSEntityDescription entityForName:@"Host" inManagedObjectContext:_managedObjectContext];
-            host.parent = [[Host alloc] initWithEntity:entity insertIntoManagedObjectContext:_managedObjectContext];
+            parent = [[Host alloc] initWithEntity:entity insertIntoManagedObjectContext:_managedObjectContext];
         }
         
         // Push changes from the temp host to the persistent one
-        [host propagateChangesToParent];
+        [host propagateChangesToParent:parent withDm:self];
         
         [self saveData];
     }];
@@ -98,14 +99,12 @@
 }
 
 - (void) removeHost:(TemporaryHost*)host {
-    if (host.parent == nil) {
-        // Not inserted into the DB
-        return;
-    }
-    
     [_managedObjectContext performBlockAndWait:^{
-        [_managedObjectContext deleteObject:host.parent];
-        [self saveData];
+        Host* managedHost = [self getHostForTemporaryHost:host];
+        if (managedHost != nil) {
+            [_managedObjectContext deleteObject:managedHost];
+            [self saveData];
+        }
     }];
 }
 
@@ -132,6 +131,33 @@
     return tempHosts;
 }
 
+// Only call from within performBlockAndWait!!!
+- (Host*) getHostForTemporaryHost:(TemporaryHost*)tempHost {
+    NSArray *hosts = [self fetchRecords:@"Host"];
+    
+    for (Host* host in hosts) {
+        if ([tempHost.uuid isEqualToString:host.uuid]) {
+            return host;
+        }
+    }
+    
+    return nil;
+}
+
+// Only call from within performBlockAndWait!!!
+- (App*) getAppForTemporaryApp:(TemporaryApp*)tempApp {
+    NSArray *apps = [self fetchRecords:@"App"];
+    
+    for (App* app in apps) {
+        if ([app.id isEqualToString:tempApp.id] &&
+            [app.host.uuid isEqualToString:app.host.uuid]) {
+            return app;
+        }
+    }
+    
+    return nil;
+}
+
 - (NSArray*) fetchRecords:(NSString*)entityName {
     NSArray* fetchedRecords;
     

Limelight/Database/TemporaryApp.h

@@ -18,15 +18,13 @@
 @property (nonatomic) BOOL isRunning;
 @property (nullable, nonatomic, retain) TemporaryHost *host;
 
-@property (nullable, nonatomic) App* parent;
-
 NS_ASSUME_NONNULL_BEGIN
 
 - (id) initFromApp:(App*)app withTempHost:(TemporaryHost*)tempHost;
 
 - (NSComparisonResult)compareName:(TemporaryApp *)other;
 
-- (void) propagateChangesToParent;
+- (void) propagateChangesToParent:(App*)parent withHost:(Host*)host;
 
 NS_ASSUME_NONNULL_END
 

Limelight/Database/TemporaryApp.m

@@ -14,8 +14,6 @@
 - (id) initFromApp:(App*)app withTempHost:(TemporaryHost*)tempHost {
     self = [self init];
     
-    self.parent = app;
-    
     self.id = app.id;
     self.image = app.image;
     self.name = app.name;
@@ -24,11 +22,11 @@
     return self;
 }
 
-- (void) propagateChangesToParent {
-    self.parent.id = self.id;
-    self.parent.image = self.image;
-    self.parent.name = self.name;
-    self.parent.host = self.host.parent;
+- (void) propagateChangesToParent:(App*)parent withHost:(Host*)host {
+    parent.id = self.id;
+    parent.image = self.image;
+    parent.name = self.name;
+    parent.host = host;
 }
 
 - (NSComparisonResult)compareName:(TemporaryApp *)other {

Limelight/Database/TemporaryHost.h

@@ -10,14 +10,14 @@
 #import "Utils.h"
 #import "Host.h"
 
+@class DataManager;
+
 @interface TemporaryHost : NSObject
 
 @property (nonatomic) BOOL online;
 @property (nonatomic) PairState pairState;
 @property (nonatomic, nullable) NSString * activeAddress;
 
-@property (nullable, nonatomic) Host* parent;
-
 NS_ASSUME_NONNULL_BEGIN
 
 @property (nonatomic, retain) NSString *address;
@@ -32,7 +32,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (NSComparisonResult)compareName:(TemporaryHost *)other;
 
-- (void) propagateChangesToParent;
+- (void) propagateChangesToParent:(Host*)host withDm:(DataManager*)dm;
 
 NS_ASSUME_NONNULL_END
 

Limelight/Database/TemporaryHost.m

@@ -6,6 +6,7 @@
 //  Copyright © 2015 Moonlight Stream. All rights reserved.
 //
 
+#import "DataManager.h"
 #import "TemporaryHost.h"
 #import "Host.h"
 #import "TemporaryApp.h"
@@ -16,8 +17,6 @@
 - (id) initFromHost:(Host*)host {
     self = [self init];
     
-    self.parent = host;
-    
     self.address = host.address;
     self.externalAddress = host.externalAddress;
     self.localAddress = host.localAddress;
@@ -37,28 +36,29 @@
     return self;
 }
 
-- (void) propagateChangesToParent {
-    self.parent.address = self.address;
-    self.parent.externalAddress = self.externalAddress;
-    self.parent.localAddress = self.localAddress;
-    self.parent.mac = self.mac;
-    self.parent.name = self.name;
-    self.parent.uuid = self.uuid;
+- (void) propagateChangesToParent:(Host*)parentHost withDm:(DataManager*)dm {
+    parentHost.address = self.address;
+    parentHost.externalAddress = self.externalAddress;
+    parentHost.localAddress = self.localAddress;
+    parentHost.mac = self.mac;
+    parentHost.name = self.name;
+    parentHost.uuid = self.uuid;
     
     NSMutableSet *applist = [[NSMutableSet alloc] init];
     for (TemporaryApp* app in self.appList) {
         // Add a new persistent managed object if one doesn't exist
-        if (app.parent == nil) {
-            NSEntityDescription* entity = [NSEntityDescription entityForName:@"App" inManagedObjectContext:self.parent.managedObjectContext];
-            app.parent = [[App alloc] initWithEntity:entity insertIntoManagedObjectContext:self.parent.managedObjectContext];
+        App* parentApp = [dm getAppForTemporaryApp:app];
+        if (parentApp == nil) {
+            NSEntityDescription* entity = [NSEntityDescription entityForName:@"App" inManagedObjectContext:parentHost.managedObjectContext];
+            parentApp = [[App alloc] initWithEntity:entity insertIntoManagedObjectContext:parentHost.managedObjectContext];
         }
         
-        [app propagateChangesToParent];
+        [app propagateChangesToParent:parentApp withHost:parentHost];
         
-        [applist addObject:app.parent];
+        [applist addObject:parentApp];
     }
     
-    self.parent.appList = applist;
+    parentHost.appList = applist;
 }
 
 - (NSComparisonResult)compareName:(TemporaryHost *)other {