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List:       openjdk-serviceability-dev
Subject:    Re: RFR(S): JDK-8210118: better jdb test diagnostics when getting "Prompt is not received during ...
From:       Chris Plummer <chris.plummer () oracle ! com>
Date:       2018-08-31 0:53:11
Message-ID: 5bde9dcb-e337-d270-e166-0f49accdc33d () oracle ! com
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Thank you Alex, Serguei, Gary, and JC for the reviews.

Chris

On 8/30/18 10:33 AM, Alex Menkov wrote:
> Looks good.
>
> --alex
>
> On 08/29/2018 21:19, Chris Plummer wrote:
>> Hi,
>>
>> Please review the following:
>>
>> https://bugs.openjdk.java.net/browse/JDK-8210118
>> http://cr.openjdk.java.net/~cjplummer/8210118/webrev.00/
>>
>> There have a been a few jdb bugs (or test bugs) that have caused 
>> tests to fail because they never get the expected jdb prompt. The 
>> only clue in the log is an abrupt termination of any jdb output, and 
>> the following error message:
>>
>> # ERROR: Caught unexpected exception while executing the test: 
>> nsk.share.Failure: Prompt is not received during 300200 milliseconds.
>>
>> Dumping the pending reply makes it a lot easier to debug most of 
>> these failures. Here's one example output with the fix in place:
>>
>> Sending command: cont
>> receiveReply FAILED due to "nsk.share.Failure: Prompt is not received 
>> during 300200 milliseconds.".
>> Pending reply output follows:
>> reply[0]: >
>> reply[1]: Breakpoint hit: Arg"thread=main", 
>> nsk.jdb.locals.locals002.locals002a.allKindsOfLocals(), line=100 bci=62
>> reply[2]: umen100                     System.out.println("Locals but no 
>> arguments"); // locals002.BREAKPOINT_LINE2
>> reply[3]:
>> reply[4]: ts bmain[1] ut no locals
>> # ERROR: Caught unexpected exception while executing the test: 
>> nsk.share.Failure: Prompt is not received during 300200 milliseconds.
>>
>> In this case we can see all sorts of extra characters in various 
>> reply lines. These characters actually come from a println that was 
>> executed after execution resumed and before the next breakpoint:
>>
>>                System.out.println("Arguments but no locals"); // 
>> locals002.BREAKPOINT_LINE1
>>
>> Having the pending reply helps a lot here. Without it, you have no 
>> idea why the main[1] prompt was never seen and might be led to think 
>> it was never sent. By looking at the pending output you can see that 
>> main[1] was sent, but it not being detected because of all the extra 
>> characters appearing on the same line.
>>
>> thanks,
>>
>> Chris
>>


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