Message Sent to Deallocated Object

[mrtristan]

So, I have TPKeyboardAvoidingScrollviews in a couple nibs. I don't really reference them in the code so they usually don't have an IBOutlet at all.

I'm experiencing an issue where I'm getting the dreaded Message Sent to Deallocated Object crash. I can reliably reproduce this by going through my applciation to a certain point, hitting a button that triggers a popToRootViewControllerAnimated:NO. I can then go to a certain screen and reliably crash the application.

The crash occurs in UIScrollView+TPKeyboadAvoidingAdditions.h here:

- (UIView*)TPKeyboardAvoiding_findFirstResponderBeneathView:(UIView*)view {
    // Search recursively for first responder
    for ( UIView *childView in view.subviews ) {
        if ( [childView respondsToSelector:@selector(isFirstResponder)] && [childView isFirstResponder] ) return childView;
        UIView *result = [self TPKeyboardAvoiding_findFirstResponderBeneathView:childView];
        if ( result ) return result;
    }
    return nil;
}

Heres some retain counts and the line it's dying on, spit out by the profiler:

Event Type  ∆ RefCt   RefCt   Timestamp   Responsible Library Responsible Caller
159 Retain  +1  5   00:28.118.466   UIKit   -[UINavigationController _startCustomTransition:]
161 Retain  +1  5   00:28.179.409   libsystem_sim_blocks.dylib  _Block_object_assign
162 Release -1  4   00:28.406.413   UIKit   _wrapRunLoopWithAutoreleasePoolHandler
163 Retain  +1  5   00:28.732.541   UIKit   __49-[UINavigationController _startCustomTransition:]_block_invoke
165 Retain  +1  5   00:28.732.602   UIKit   -[UINavigationController navigationTransitionView:didEndTransition:fromView:toView:]
167 Release -1  3   00:28.732.634   UIKit   __49-[UINavigationController _startCustomTransition:]_block_invoke
169 Release -1  1   00:28.732.819   UIKit   __destroy_helper_block_119
170 Retain  +1  2   00:32.284.697   UIKit   -[UINavigationController popToViewController:transition:]
171 Retain  +1  3   00:32.284.765   UIKit   -[UIViewController removeChildViewController:]
172 Retain  +1  4   00:32.284.766   UIKit   -[UIViewController removeChildViewController:notifyDidMove:]
173 Release -1  3   00:32.284.779   UIKit   -[UIViewController removeChildViewController:notifyDidMove:]
174 Release -1  2   00:32.284.780   UIKit   -[UIViewController removeChildViewController:notifyDidMove:]
175 Release -1  1   00:32.284.785   UIKit   -[UIViewController removeChildViewController:]
176 Retain  +1  2   00:32.284.799   UIKit   -[UINavigationController popToViewController:transition:]
177 Release -1  1   00:32.291.358   GraphicsServices    GSEventRunModal
178 Release -1  0   00:32.291.894   GraphicsServices    GSEventRunModal
179 Zombie      -1  00:55.265.379   UIKit   -[UIResponder(Internal) _responderWindow]

whatcha think? this issue is triggered by me calling becomeFirstResponder on a textview in viewDidAppear. It works fine unless I go through the application a little first. I dont understand where the hook is that could cause this... is there some way the lilbrary could be holding on to a reference to one of my VC's? Could it be related to the notifications that get observed for & posted?

thanks for the great library!

[michaeltyson]

Hmm, interesting. What's the full stack trace at the time of the crash?

[mrtristan]

The AddCardDetailsViewController that you see here is the new view that has the textview that I'm calling becomeFirstResponder on. The whole Message sent to deallocated object is referencing a view that i popped and am not retaining any references to. The reference count chart that I put up top is to demonstrate that I'm really not keeping it around at all... I don't understand how that message is going to that thing.

[mrtristan]

at the time of the crash, this method

- (UIView*)TPKeyboardAvoiding_findFirstResponderBeneathView:(UIView*)view {
    // Search recursively for first responder
    for ( UIView *childView in view.subviews ) {
        if ( [childView respondsToSelector:@selector(isFirstResponder)] && [childView isFirstResponder] ) return childView;
        UIView *result = [self TPKeyboardAvoiding_findFirstResponderBeneathView:childView];
        if ( result ) return result;
    }
    return nil;
}

has the following properties:
childView is a UITextField
view is a TPKeyboardAvoidingScrollView
self is a TPKeyboardAvoidingScrollview

[mrtristan]

also, just tested on iOS6.1 to compare and it does not occur. only seems to be on iOS7.

i deleted a previous comment to keep clarity here and try and make all of this a little more concise.

I've narrowed down the scenario to be:
iOS7/iOS7.1, not iOS6.1
push a view controller with a TPKeyboardAvoidingScrollView on it.
pop to previous view controller
try and show the keyboard by selecting any search bar or text view
the above crash will occur

[shakhmin]

I implemented next method in my category on TPAvoidingKeyboardScrollView:

• (UIView *)TPKeyboardAvoiding_findFirstResponderBeneathView:(UIView *)view
  {
  for (UIView *childView in [view subviews])
  {
  if ([childView isKindOfClass:[UIResponder class]] && [childView respondsToSelector:@selector(accessoryView)] && [childView isFirstResponder])
  {
  return childView;
  }

  UIView *result = [self TPKeyboardAvoiding_findFirstResponderBeneathView:childView];
  
  if (result != nil)
  {
      return result;
  }
  

  }

  return nil;
  }

It works for me.