Mihai Chira created FLEX-34119:
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Summary: 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 4.11.0
Reporter: Mihai Chira
Fix For: Apache Flex 4.12.0
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 shows all the configurations of the model
collection-view that I constructed which cause the RTE.
Notations:
[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.
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