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https://issues.apache.org/jira/browse/FLEX-34119?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mihai Chira updated FLEX-34119:
-------------------------------

    Attachment: BookmarkErrorScenarios.txt

> mx.collections.HierarchicalCollectionViewCursor causes CursorError RTE from 
> ListCollectionView when the underlying collections change
> -------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: FLEX-34119
>                 URL: https://issues.apache.org/jira/browse/FLEX-34119
>             Project: Apache Flex
>          Issue Type: Bug
>          Components: Advanced Data Grid
>    Affects Versions: Apache Flex 4.12.1
>            Reporter: Mihai Chira
>            Assignee: Mihai Chira
>              Labels: collections, cursors, easytest
>             Fix For: Apache Flex 4.12.0
>
>         Attachments: BookmarkErrorScenarios.txt, 
> _HierarchicalCollectionViewCursorBug.fxp
>
>
> *Steps to reproduce A*:
> # Run the unit test called HierarchicalCollectionViewCursor_FLEX_34119_Test 
> in the "FLEX-34119" branch against the HierarchicalCollectionViewCursor class 
> in the develop branch. You should see lots of "Bookmark no longer valid" 
> errors.
> *Steps to reproduce B*:
> # Run the attached AIR project. (Avoid debug mode unless you want to press F8 
> MANY times). It will take around 10s.
> The unit test (HierarchicalCollectionViewCursorTest.as) shows many of the 
> ways in which HierarchicalCollectionViewCursor's state can make 
> ListCollectionView fail through a seek() operation on 
> ListCollectionViewCursor by allowing a CursorError to be thrown from 
> ListCollectionView.getBookmarkIndex() (I say 'allowing' because it could 
> easily prevent it).
> The (long) trace output (viewable in debug mode) shows all the configurations 
> of the collection-view that I constructed which cause the RTE.
> *Notations in trace output*:
> * [SEL] - the currently selected item by the HierarchicalCollectionViewCursor 
> (cursor.current).
> * [INS] - the newly inserted item, which caused the RTE
> * [REPL] - the item which, when replaced, causes the RTE (notice there's only 
> one such instance - when the (selected) second stage is replaced with another 
> item).
> *NOTES*:
> * for us this has caused numerous, apparently mysterious bugs within 
> AdvancedDataGrids which boiled down to one or other of these configurations.
> * The reproduceCursorErrorWithDisableAutoUpdate() test shows that the error 
> can also be thrown by not allowing the HierarchicalCollectionView (and, 
> implicitly, the HierarchicalCollectionViewCursor) to know about changes in 
> the underlying collections (by using disableAutoUpdate() in conjunction with 
> refresh() and enableAutoUpdate()). We were using these methods to optimise 
> expensive updates in the collections shown in the AdvancedDataGrids, without 
> realising they had a knock-on effect on the HierarchicalCollectionView used 
> by the grids. This part of the error-generation scenario is controlled by the 
> programmers, of course, but it might be worth documenting, so that others can 
> avoid these issues.
> * I found one bug report which hints at these problems, but it doesn't seem 
> to have kept its attachment: FLEX-33054. The last comment shows the exact 
> part of the code which calls seek(), thus generating the RTE.
> *The RTE that's usually thrown*:
> Main Thread (Suspended: Error: Bookmark no longer valid.)     
>       
> mx.collections::HierarchicalCollectionViewCursor/collectionChangeHandler      
>   
>       flash.events::EventDispatcher/dispatchEventFunction [no source] 
>       flash.events::EventDispatcher/dispatchEvent [no source] 
>       
> mx.collections::HierarchicalCollectionView/nestedCollectionChangeHandler      
>   
>       flash.events::EventDispatcher/dispatchEventFunction [no source] 
>       flash.events::EventDispatcher/dispatchEvent [no source] 
>       mx.collections::ListCollectionView/dispatchEvent        
>       mx.collections::ListCollectionView/addItemsToView       
>       mx.collections::ListCollectionView/listChangeHandler    
>       flash.events::EventDispatcher/dispatchEventFunction [no source] 
>       flash.events::EventDispatcher/dispatchEvent [no source] 
>       mx.collections::ArrayList/internalDispatchEvent 
>       mx.collections::ArrayList/addItemAt     
>       mx.collections::ListCollectionView/addItemAt



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