8078891: java.io.SequenceInputStream.close is not atomic and not idempotent

[Alan Bateman]

On 26/07/2019 16:41, Brian Burkhalter wrote:
> :
> Please see the updated patch which switches the implementation to the amended version and incorporates the proposed change to the test:
>
> http://cr.openjdk.java.net/~bpb/8078891/webrev.01/
The bug summary might be a big misleading as SequenceInputStream isn't 
thread safe and close isn't atomic. The changes are really to attempt to 
close all the remaining streams rather than bailing out when closing one 
of them fails.

In any case, the change looks okay but it might be simpler to 
restructure to use:

while (in != null) {
     try { in.close() } catch (IOException e) { ... }
     peekNextStream();
}

to simplify the error handling and avoid mixing nextStream and 
peekNextStream. There is also some curious code in peekNextStream where 
it handles nextElement returning null - I don't know the history on that 
but it looks like it's trying to handling a broken Enumeration.

-Alan