RFR(S): 8227255: Switchable helpful NullPointerExceptions

[David Holmes]

Hi Goetz,

On 4/07/2019 8:59 pm, Lindenmaier, Goetz wrote:
> Hi David,
> 
> the implementation of the JEP is to be found here:
> https://bugs.openjdk.java.net/browse/JDK-8218628
> http://cr.openjdk.java.net/~goetz/wr19/8218628-exMsg-NPE/12/
> 
> I thought it's good to keep different aspects in changes of their
> own

I expect to see one issue being used to push a complete implementation 
for a JEP. Independent parts unrelated to the actual JEP can be split 
off but anything dependent on the JEP should be done all together.

> also as I need two CSRs: one to mention there are new messages
> and one to mention there is a new flag.

You can use one CSR, for 8218628, to cover all aspects.

David
------

> It also simplifies reviews a lot.
> 
> Best regards,
>    Goetz.
> 
>> -----Original Message-----
>> From: David Holmes <david.holmes at oracle.com>
>> Sent: Donnerstag, 4. Juli 2019 12:52
>> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; hotspot-runtime-
>> dev at openjdk.java.net
>> Cc: Coleen Phillimore (coleen.phillimore at oracle.com)
>> <coleen.phillimore at oracle.com>
>> Subject: Re: RFR(S): 8227255: Switchable helpful NullPointerExceptions
>>
>> Sorry Goetz but I am confused by this. You have a JEP that is still in
>> draft but here you have a RFR for a change related to that JEP but not
>> the implementation of that JEP ??? I only expect to see one issue filed
>> to implement that JEP including the creation of the flag to
>> enable/disable it.  The introduction of the flag should be part of the
>> JEP as well.
>>
>> That said you may as well get the CSR going in parallel with the JEP.
>>
>> David
>>
>> On 4/07/2019 8:35 pm, Lindenmaier, Goetz wrote:
>>> Hi,
>>>
>>> please review this small change.
>>>
>>> http://cr.openjdk.java.net/~goetz/wr19/8227255-NPE-switchable/01/
>>>
>>> It will be part of JEP 8220715.
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8220715
>>>
>>> The exception messages proposed there will first be
>>>
>>> off per default. After gathering experience, they
>>>
>>> will be turned on per default.
>>>
>>> I was asked to use a manageable flag so it can be switched
>>>
>>> by jcmd.
>>>
>>> The flag: SuppressCodeDetailsInExceptionMessages
>>>
>>>     "Suppress"  because the feature is meant to be on per
>>>
>>>                          default in the long run. Then you'll have to
>>>
>>>                          use -XX:_+_ if using the switch.
>>>
>>>     "CodeDetails" tries to summarize the concerns with
>>>
>>>     the message.
>>>
>>> The flag does not mention NPE so it can  be used in
>>>
>>> other, similar cases.
>>>
>>> If there are not objections to the flag name, I'll file a
>>>
>>> CSR.  Or should I wait with the CSR until the JEP is
>>>
>>> targeted?
>>>
>>> Best regards,
>>>
>>>     Goetz.
>>>