Performing operations on objects within nested contexts where the MR_…

…inContext: method was used was throwing errors when objects with tempID's were being passed to the method. The solution was to check if the ID is temporary and then if it is, request a permanentID before continuing.

MagicalRecord/Categories/NSManagedObject/NSManagedObject+MagicalRecord.m

@@ -221,6 +221,17 @@ + (BOOL) MR_truncateAll
 
 - (id) MR_inContext:(NSManagedObjectContext *)otherContext
 {
+    NSManagedObjectID *objectID = [self objectID];
+    if ([objectID isTemporaryID]) {
+        MRLog(@"Object (%@) has temporaryID. Attempting to generate permanentID.",[[self class] description]);
+        NSError *error = nil;
+        if ([[self managedObjectContext] obtainPermanentIDsForObjects:[NSArray arrayWithObject:self] error:&error]) {
+            objectID = [self objectID];
+            MRLog(@"Object (%@) was granted a permanentID.",[[self class] description]);
+        } else {
+            [MagicalRecord handleErrors:error];
+        }
+    }
     NSError *error = nil;
     NSManagedObject *inContext = [otherContext existingObjectWithID:[self objectID] error:&error];
     [MagicalRecord handleErrors:error];