Files.copy(InputStream, Path, CopyOption...) can fail with OOM if direct memory is limited

[Alan Bateman]

On 12/09/2023 22:39, github at paul.kungfoocoder.org wrote:
> Agreed. My question is what is the next step now that I have 
> identified this problem? Do others agree that this is something that 
> should be fixed? What can I do to move this forward?
>
We have to proceed with caution. You pointed to IOUtil.write in your 
original mail but changing ityo  limit the size of the temporary direct 
buffer will likely break existing code/usage that don't correct checking 
the return value. We found two cases in the JDK code and it seems likely 
are more in the wider eco system. Limiting in the adaptor classes (the 
classes returned by Channels.newInputStream and newOutputStream) reduces 
the impact but we still need to be cautious as there may be code that 
reads from an input stream and isn't checking for "short reads". For the 
specific scenario here then it may be that BIS.transferTo just needs to 
be changed to write chunks to the target output stream.

-Alan