<Swing Dev> Webrev for NPE at BasicTreeUI$Actions.page:4470

[Alexander Scherbatiy]

On 11/21/2012 1:02 PM, Jaroslav Tulach wrote:
> Here is my proposed fix:
> http://xelfi.cz/webrev/NB222081/
    The fix looks good for me.
> I created an automated test, but it is just artificial one - it returns null
> for no reason and only checks the caller is ready for such situation. That is
> the best I was able to come up.
      That is fine.
>>       At least you can run the test/javax/swing/JTree  automated test to
>> check possible regressions.
> - e.g. I am almost sure that my patch causes no regressions.
>
> Btw. I included artificial bug number 9999999 in the test right now (as there
> is no bugtraq/bugdb report for the NPE afaik). I also tried to reference the
> NetBeans bug (by name of the directory and test). I can of course change that
> according to your suggestions.
       I have created an issue on it: 8003830 NullPointerException at 
javax.swing.plaf.basic.BasicTreeUI$Actions.page
       Please, use this number for the test name.

       The updated webrev should be put to cr.openjdk.java.net (you 
could ask anyone from this alias to do that).
       Please, use the following email as a template for the updated 
review request.
           
http://mail.openjdk.java.net/pipermail/swing-dev/2012-June/002150.html

       Thanks,
       Alexandr.

> Thanks in advance for your review.
> -jt
>
>>> Dne Pá 16. listopadu 2012 15:30:00, Alexander Scherbatiy napsal(a):
>>>> On 11/15/2012 7:58 PM, Jaroslav Tulach wrote:
>>>>> Dear Swing maintainers,
>>>>> my name is Jaroslav Tulach and I am maintaining NetBeans explorer - a
>>>>> component that is using JTree heavily.
>>>>>
>>>>>>    From time to time I receive a user report with a NPE from Swing where
>>>>>>
>>>>>> little>
>>>>> or even no NetBeans code involved. Just today I got
>>>>> http://netbeans.org/bugzilla/show_bug.cgi?id=222081
>>>>> We have about 35 other ones (which is not that much given the fact we
>>>>> have
>>>>> million of users), but still...
>>>>>
>>>>> According to
>>>>> http://statistics.netbeans.org/exceptions/exception.do?id=628832
>>>>> the report comes from jdk7u9-b05. The source code is here
>>>>> http://hg.openjdk.java.net/jdk7u/jdk7u/jdk/file/jdk7u9-
>>>>> b05/src/share/classes/javax/swing/plaf/basic/BasicTreeUI.java
>>>>> and thus it looks like the call on line 4468 to
>>>>>
>>>>> ui.getPathBounds(tree, newPath);
>>>>>
>>>>> can return null (under some rare and unknown circumstances).
>>>>>
>>>>> I can close the bug #222081 as "worksforme", but it is clear that such
>>>>> error happens from time to time and we don't want our users to face
>>>>> errors. A simple:
>>>>>
>>>>> 4469 if (newRect == null) return;
>>>>>
>>>>> would do the trick. One question remains: if I try to donate such patch,
>>>>> will you accept it?
>>>>>
>>>>        The ui.getPathBounds(tree, newPath) method definitely can return
>>>>
>>>> null so it needs to have this check.
>>>>
>>>>        However, such fix can mask the real issue, for example, in the
>>>>
>>>> treeState.getBounds() method where the  treeState can be instance of
>>>> FixedHeightLayoutCache or VariableHeightLayoutCache class.
>>>>
>>>>        If it is possible, could you send a code snippet that shows how
>>>>
>>>> NetBeans uses JTree? May be it can give a hint what can be wrong in this
>>>> case.
>>>>
>>>>        Thanks,
>>>>        Alexandr.
>>>>> -jt