I found a bug in the UITableView under iOS7. This little piece of code will produce a memory leak, when I call the method 'reloadSections' from UITableView. When this happens, the Table-Object will retained from anywhere in the library. How you can check this?
- Open the App
- When you click on 'Count' you can see, how many cells will be allocated.
- Wait a minute, so that a section is reloaded. The count of cell will be increased, but thats not a problem.
- Click on a cell, so that a new controller is shown. Wait a moment so that the cell will be reloaded. More cells will be allocated, but thats not a problem at all.
- Go back and then take a look at the count. It's not going down, but the cell should be deallocated!
If you go back before the cells are reloaded, everything is still fine. If you run the steps under iOS6, everything is still fine. If you take a deeper look in instruments for the second table, you see something like this:
0 Malloc +1 1 00:08.857.342 AppleBugTest -[ViewController viewDidLoad]
1 Retain +1 2 00:08.857.753 AppleBugTest -[ViewController setTableView:]
2 Release -1 1 00:08.857.754 AppleBugTest -[ViewController viewDidLoad]
3 Retain +1 2 00:08.857.756 AppleBugTest -[ViewController viewDidLoad]
4 Release -1 1 00:08.857.818 AppleBugTest -[ViewController viewDidLoad]
5 Retain +1 2 00:08.857.820 AppleBugTest -[ViewController viewDidLoad]
6 Release -1 1 00:08.858.046 AppleBugTest -[ViewController viewDidLoad]
7 Retain +1 2 00:08.858.229 AppleBugTest -[ViewController viewDidLoad]
8 Retain +1 3 00:08.858.271 UIKit -[UIView(Internal) _addSubview:positioned:relativeTo:]
9 Release -1 2 00:08.858.314 AppleBugTest -[ViewController viewDidLoad]
10 Retain +1 3 00:08.858.391 AppleBugTest -[ViewController viewWillAppear:]
11 Retain +1 4 00:08.858.483 Foundation -[NSConcreteNotification initWithName:object:userInfo:]
12 Release -1 3 00:08.858.599 AppleBugTest -[ViewController viewWillAppear:]
13 Retain +1 4 00:08.858.963 UIKit -[UIView(Hierarchy) subviews]
Retain/Release (8) 00:08.876.182 QuartzCore -[CALayer layoutSublayers]
Retain/Release (18) 00:08.876.328 AppleBugTest -[ViewController tableView:cellForRowAtIndexPath:]
36 Release -1 3 00:08.893.061 Foundation -[NSConcreteNotification dealloc]
37 Retain +1 4 00:11.858.958 AppleBugTest __33-[ViewController viewWillAppear:]_block_invoke
38 Retain +1 5 00:11.859.533 UIKit -[_UITableViewUpdateSupport initWithTableView:updateItems:oldRowData:newRowData:oldRowRange:newRowRange:context:]
Retain/Release (8) 00:11.859.948 AppleBugTest -[ViewController tableView:cellForRowAtIndexPath:]
47 Retain +1 6 00:11.865.044 libsystem_sim_blocks.dylib _Block_object_assign
Retain (15) +15 00:11.865.113 libsystem_sim_blocks.dylib _Block_object_assign
63 Release -1 20 00:11.868.793 UIKit -[_UITableViewUpdateSupport dealloc]
64 Release -1 19 00:11.868.894 AppleBugTest __33-[ViewController viewWillAppear:]_block_invoke
69 Release -1 18 00:13.127.727 UIKit -[UIViewController dealloc]
70 Release -1 17 00:13.127.985 UIKit -[UIView(Internal) _invalidateSubviewCache]
71 Release -1 16 00:13.128.033 UIKit -[UIView(Hierarchy) removeFromSuperview]
The row after #47: Here we have 15 retains! That does not look very good.