RFR: 6616245: NullPointerException when using JFileChooser with a custom FileView [v2]

[Alexey Ivanov]

On Mon, 3 Oct 2022 12:09:26 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

>> In other L&F the same problem exist, but NPE is does not occurs because previous state check is not done, directly the clicked file is been set. 
>> https://github.com/openjdk/jdk/blob/ccc1d3169691d066c08e294f5d989b007bfab114/src/java.desktop/windows/classes/com/sun/java/swing/plaf/windows/WindowsFileChooserUI.java#L1328
>
>> Well, the logic there tries to prevent the current directory from becoming `null`. Yet it traverses up the tree:
>> 
>> https://github.com/openjdk/jdk/blob/ccc1d3169691d066c08e294f5d989b007bfab114/src/java.desktop/share/classes/javax/swing/JFileChooser.java#L603-L607
>> 
>> Probably, if `dir` becomes `null` in the end, it should resort to its default behaviour: `getFileSystemView().getDefaultDirectory()`. Or not change at all?
> 
> This behaviour is specified. https://github.com/openjdk/jdk/blob/ccc1d3169691d066c08e294f5d989b007bfab114/src/java.desktop/share/classes/javax/swing/JFileChooser.java#L576-L580
> 
> Yet it doesn't take into account a custom implementation of `FileSystem` which does not allow navigating up. It may be a problem in `FileSystem` implementation.

> In other L&F the same problem exist, but NPE is does not occurs because previous state check is not done, directly the clicked file is been set.
> 
> https://github.com/openjdk/jdk/blob/ccc1d3169691d066c08e294f5d989b007bfab114/src/java.desktop/windows/classes/com/sun/java/swing/plaf/windows/WindowsFileChooserUI.java#L1328

Maybe it's the way to go for Metal too? I mean call `setCurrentDirectory` unconditionally.

What do other L&Fs do?

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PR: https://git.openjdk.org/jdk/pull/10485