RFR 8185108: JShell: NullPointerException when throwing exception with null message under local ExecutionControl

[Robert Field]

On 08/23/17 12:42, Jan Lahoda wrote:
> Overall, looks OK.
>
> I wonder if we can send a marker bit (null/non-null) optionally 
> followed by the UTF String instead of a marker UTF/text?

That would be cleaner, but I choose not to do that as it would make the 
protocol incompatible between 9 and 10.

Thanks,
Robert

>
> Thanks,
>     Jan
>
> On 19.8.2017 02:00, Robert Field wrote:
>> Please review fixes to handling of SnippetEvent.exception().getMessage()
>>
>> Bug:
>>
>>      https://bugs.openjdk.java.net/browse/JDK-8185108
>>
>> Webrev:
>>
>>      http://cr.openjdk.java.net/~rfield/8185108v0.webrev/
>>
>> Issues addressed --
>>
>> (1) Original issue: using API and DirectExecutionControl (which was not
>> intended for direct use), user exceptions with no message (null message)
>> crashes eval()
>>
>> (2) Like (1) above with LocalExecutionControlProvider (which is intended
>> for direct use)
>>
>> (3) Because of (2), "jshell --execution local" crashes with the input
>> "throw new java.io.IOException();"
>>
>> (4) Under default ExecutionControl, exceptions with null messages
>> actually return an empty string message in the API.
>>
>> (5) Because of (4), the default configuration of the jshell tool
>> displays a colon that it shouldn't for "throw new 
>> java.io.IOException();"
>>
>> (6) Handling of the streaming representation of a null message was being
>> handled in the jdk.jshell package (Eval.java) whereas it should be
>> handled in the streaming ExecutionControl support.
>>
>> (7) The poorly placed implementation of (6) was out-of-sync with the
>> behavior of the streaming ExecutionControl support, being the immediate
>> cause of (4)
>>
>>