Objective-C : Incorrect reference counter decrement

Reference counter is being incorrectly reduced for an object, which the caller no longer owns. This may lead to incorrect behavior or crash of the application.

Objective C uses the standard mechanism of reference counting: every created object that inherits NSObject/NSProxy has an internal reference counter that after creation is set equal to one. To increase the reference count on the object call the retain and to decrement the reference count call the release. Once the reference count reaches 0, object is deallocated. Calling the release for the object, which the caller no longer owns, may lead to undefined behavior.