RFR(S): 8198655: test/lib/jdk/test/lib/apps/LingeredApp shouldn't inherit cout/cerr

[Chris Plummer]

On 3/16/18 1:25 PM, serguei.spitsyn at oracle.com wrote:
> Hi Chris,
>
> Thank you for taking care about this issue!
>
> On 3/16/18 11:20, Chris Plummer wrote:
>> Hi,
>>
>> I've resolved the issues I had before with not seeing all the stderr 
>> output when I tried to capture it. What I'd like to do now is have us 
>> decide how the output should be handled from the perspective a 
>> LingeredApp user (driver app). Currently all LingeredApp stdout is 
>> captured and gets be returned the the driver app by calling 
>> app.getAppOutput(). It does not appear in the .jtr file, but the test 
>> would have the option of dumping it there it it cared to. Only one 
>> test uses app.getAppOutput(). Currently all the LingeredApp stderr is 
>> redirected to the console, so it does not appear in the .jtr file.
>
> Just a general comment to make sure I understand it and ensure we are 
> in sync.
> It seems much more safe to always have both stdout and stderr outputs 
> present in the .jtr automatically file independently of of what the 
> test does.
>
>
>> So how do we want this changed? Some possibilities are:
>>
>> (1) capture stderr just like stdout currently is, and leave is up the 
>> the driver app to decide if it wants to display it (after the app 
>> terminates).
>
> It does not look good to me (see above) but maybe I'm missing 
> something important here.
>
>> (2) capture stderr just like stdout currently is, but have 
>> LingeredApp automatically send captured output to driver app's stdout 
>> and stderr (after the app terminates).
>
> The stdout and std err will be separated in this case, right?
> Do you have a webrev for this?
I currently have it working like this, although I need to fix 
LingeredApp.getAppOutput(). I had to make it return a single String 
instead of a List of Strings, so this breaks the one test that uses this 
API. It's easily fixed. Just haven't gotten around to it yet.
>
>
>> (3) send the LingeredApp's stdout and stderr to the driver app's 
>> stdout as it is being captured (this was the original fix Igor 
>> suggested and the webrev supported). A minor alternative to this is 
>> to keep the two streams separated instead of sending both to stdout.
>>
>> Let me know what you think. I'm inclined to go with 2, especially 
>> since normally there is little to no output from the LingeredApp.
>
> The choice (2) looks good enough.
> Not sure it is that important to have output from stdout and stderr 
> sync'ed
> but is is important to have the stderr present in the .jtr automatically.
>
> The choice (3) looks even better if it is going to work well.
This is basically what the original webrev did. It sent LingeredApp's 
stderr and stdout to the the driver apps stdout. It's a 1 word change to 
make it send stderr to stderr. I think it has a bug though that did not 
manifest itself. It seems the new copy() code that is capturing stdout 
would be contending with the existing InputGlobbler code that is doing 
the same. I would need to fix this to make sure 
LingeredApp.getAppOutput() still returns all the apps stdout output.

Chris
> Not sure, it is really necessary.
>
> Thanks,
> Serguei
>
>
>>
>> BTW, here's the CR and original webrev for reference:
>>
>> https://bugs.openjdk.java.net/browse/JDK-8198655
>> http://cr.openjdk.java.net/~cjplummer/8198655/webrev.00/webrev/
>>
>> thanks,
>>
>> Chris
>>
>