RFR: 8293862: javax/swing/JFileChooser/8046391/bug8046391.java failed with 'Cannot invoke "java.awt.Image.getWidth(java.awt.image.ImageObserver)" because "retVal" is null'

[Tejesh R]

On Tue, 15 Nov 2022 15:39:24 GMT, Alexey Ivanov <aivanov at openjdk.org> wrote:

> > Yeah, the only way the retVal can become null would-be if `resolutionVariants` doesn't have an Icon. I could not reproduce the bug since it is intermittent, I came to this conclusion only by code analysis though. Should I check for `resolutionVariants` if its empty and return null without proceeding further......? I guess both the ways `null` will be returned?
> 
> An MRI that has no images does not make any sense, we should've returned null.
> 
> There are two usages of the constructor which accepts resolution variants:
> 
> https://github.com/openjdk/jdk/blob/6c8d0e617ff59eee1313589b10edbf5830774db5/src/java.desktop/windows/classes/sun/awt/shell/Win32ShellFolder2.java#L1185
> 
> 
> https://github.com/openjdk/jdk/blob/6c8d0e617ff59eee1313589b10edbf5830774db5/src/java.desktop/windows/classes/sun/awt/shell/Win32ShellFolder2.java#L1112-L1113
> 
> There are four usages of the other constructor which accepts an image.
> 
> Since it's an intermittent problem, we need to add debugging code to the code which creates the `MultiResolutionIconImage` object or handle the exceptional cases in the constructor… by adding an `assert` statement. The tests are run with asserts enabled and we may get more data.
> 
> Is there a host where the test is more likely to fail? Does it fail on different hosts?
> 
> Adding the null check to `getResolutionVariant` does not fix the root cause. Instead, it'll make it impossible to find the root cause because everything would look as if no problem exists.

Yeah, agree to your point that it actually mask the actual problem. It fails only when windows L&F is used and `JFileChooser` is instantiated. On creating file chooser instance on windows `getSystemIcon` is called initiates the problem.

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PR: https://git.openjdk.org/jdk/pull/11104