RFR JDK-8031554: com/sun/tools/attach/BasicTests.java fails intermittently

[shanliang]

Jaroslav Bachorik wrote:
> Hi Shanliang,
>
> On 07/01/2014 09:47 PM, shanliang wrote:
>> I am still thinking to keep the original fix, because:
>> 1) to throw InterruptedException does not fix the test failure, it might
>> give more info for diagnostics. If it was really caused by an
>> InterruptedException, then to fix the issue we still need to know who
>> could interrupt the test main thread, in which case and why, and whether
>> possible to ignore it (skip the test or try again?).
>
> I'm sorry but I can't agree with this. The proposed patch does not add 
> anything else than making the InterruptedException visible. Adding 
> process.waitFor() will solve nothing as it is already called by 
> ProcessTools.getOutput(process) while creating OutputAnalyzer.
>
>> 2) the test library is used also by other tests and to modify it might
>> make new fail, it is better to concentrate at first on a single test
>> before knowing the exact cause.
>
> I wouldn't expect new failures - when an InterruptedException was 
> thrown the ProcessTools.executeTestJvm(args) returned null. Either the 
> test would fail with NPE or custom assert - it makes no sense to work 
> with "null" process.
>
> IMO, this should be fixed in the test library.
Sorry I may miss something here, you suggested:
    "Either the result of ProcessTools.getOutput() should be checked for 
null to detect this situation or ProcessTools.getOutput() should throw a 
more aggressive exception when waitFor() gets interrupted."

We still need to do something when an InterruptedException happens, skip 
the test or retry? before making a decision we should know why there was 
an InterruptedException and in which case, I really do not have any 
idea, and I do not want to exclude other possibilities.

Yes what my fix does is to expose an InterruptedException if it happens, 
but it could make sure that it was really because of an 
InterruptedException.

About new failure, there could be a negative test  which expected a 
IllegalStateException --> failed OutputAnalyser, who knows.

Shanliang
>
> -JB-
>
>>
>> Shanliang
>>
>> Christian Tornqvist wrote:
>>>
>>> I can’t remember if there was a reason for doing it like this, but it
>>> seems reasonable to not catch the InterruptedException in getOutput().
>>>
>>> Thanks,
>>>
>>> Christian
>>>
>>> *From:*Staffan Larsen [mailto:staffan.larsen at oracle.com]
>>> *Sent:* Friday, June 27, 2014 4:49 AM
>>> *To:* shanliang
>>> *Cc:* Jaroslav Bachorik; serviceability-dev at openjdk.java.net
>>> serviceability-dev at openjdk.java.net; Christian Tornqvist
>>> *Subject:* Re: RFR JDK-8031554: com/sun/tools/attach/BasicTests.java
>>> fails intermittently
>>>
>>> It does look suspicious to catch and ignore the InterruptedException,
>>> especially since the OutputAnalyzer constructor will fail in this case.
>>>
>>> Christian is the original author of these classes: do you know if
>>> there is a good rationale for doing this? Or should we propagate the
>>> InterruptedException?
>>>
>>> Thanks,
>>>
>>> /Staffan
>>>
>>> On 26 jun 2014, at 17:24, shanliang <shanliang.jiang at oracle.com
>>> <mailto:shanliang.jiang at oracle.com>> wrote:
>>>
>>>
>>>
>>>     Jaroslav Bachorik wrote:
>>>
>>>         Hi Shanliang,
>>>
>>>         On 06/26/2014 03:15 PM, shanliang wrote:
>>>
>>>             Hi,
>>>
>>>             Today ProcessTools.executeProcess has the code:
>>>                 new OutputAnalyzer(pb.start());
>>>
>>>             and OutputAnalyzer constructor calls immediately:
>>>                 exitValue = process.exitValue();
>>>
>>>             the test got exception because the process did not end.
>>>
>>>
>>>         Are you sure about this?
>>>
>>>         The OutputAnalyzer constructor, before calling
>>>         process.exitValue(), calls ProcessTools.getOutput(process)
>>>         which actually does process.waitFor()
>>>
>>>     Good catch!
>>>
>>>
>>>         A probable explanation would be that process.waitFor() gets
>>>         interrupted without the target process actually ending.
>>>
>>>         Either the result of ProcessTools.getOutput() should be
>>>         checked for null to detect this situation or
>>>         ProcessTools.getOutput() should throw a more aggressive
>>>         exception when waitFor() gets interrupted.
>>>
>>>     It was possible beacause of an InterruptedException, but maybe a
>>>     Process issue too.
>>>
>>>     process.waitFor() was called by the test main thread, I am
>>>     wondering who wanted to interrupt this thread?
>>>
>>>     Not know why ProcessTools.getOutput() catches InterruptedException
>>>     and then returns null, are there some other tests dependent to
>>>     this behavior? otherwise better to not catch InterruptedException.
>>>
>>>     I think to keep this modification, it will allow us to get more
>>>     information if the bug is reproduced, if getting an
>>>     InterruptedException then we need to do more investigation for
>>>     why, if no exception then we may rise a question to 
>>> process.waitFor().
>>>
>>>     Shanliang
>>>
>>>
>>>         -JB-
>>>
>>>
>>>
>>>             So a direct solution for the test is not to call:
>>>                    ProcessTools.executeTestJvm(args);
>>>
>>>             but:
>>>                     ProcessBuilder pb =
>>>             
>>> ProcessTools.createJavaProcessBuilder(Utils.addTestJavaOpts(args));
>>>                     Process process = pb.start();
>>>                     process.waitFor();
>>>                     OutputAnalyzer output = new 
>>> OutputAnalyzer(process);
>>>
>>>             here we do waiting:
>>>                     process.waitFor();
>>>             before constructing an OutputAnalyzer.
>>>
>>>             ProcessTools is a tool class we may have same issue for
>>>             other tests
>>>             using this class. So we may need to improve the test 
>>> library.
>>>
>>>             bug: https://bugs.openjdk.java.net/browse/JDK-8031554
>>>             webrev: http://cr.openjdk.java.net/~sjiang/JDK-8031554/00/
>>>             <http://cr.openjdk.java.net/%7Esjiang/JDK-8031554/00/>
>>>
>>>
>>>             Thanks,
>>>             Shanliang
>>>
>>
>