core data - Why does an unsaved managedObject lose its managedObjectContext -

currently, developing app book cars. booking related data stored in entity 'bookings'. attributes of 'bookings' or relationships between 'bookings' , other enties mandatory decided add managedobjects of entity 'bookings' own managedobjectcontext. context stored in separate variable avoid losing it. works fine unless i'll sign (enterprise store or adhoc) app , deploy it. arc enabled.

class bookings interface

@interface bookings : nsmanagedobject { @private      nsmanagedobjectcontext *mcontext; }  @end 

class bookings implementation

@implementation bookings {      + (bookings *)booking {          nsmanagedobjectcontext *context = [[nsmanagedobjectcontext alloc] initwithconcurrencytype:concurrencytype];          [context setpersistentstorecoordinator:[self persistentstorecoordinator]];           bookings *object = (bookings*)[[nsmanagedobject alloc] initwithentity:[self entityforname:pname] insertintomarenagedobjectcontext:context];          [object setsomereservationdata:...];          ...           // here store context in ivar of booking object          [object->mcontext = context];           return object;     } } 

at state booking object not saved!

class bookingsvc

bookings *booking = [bookings booking]; nslog(@"context: %@", [booking managedobjectcontext]); 

nothing saved or altered context null.

console output on device (adhoc signed , deployed via iphone-configurator or testflight)

... context: (null) 

console output on simulator or device (adhoc signed installed via xcode)

... context: <nsmanagedobjectcontext: 0x893c520> 

so why unsaved managedobject lose managedobjectcontext , how can avoided? bug or expected behavior?

your context nullified @ end of function. see here
object disowned context making properties null, in debug mode there exists autorelease pool keeping context being deallocated.