Request for review (XXS): JDK-8004066: TEST_BUG: test/java/lang/Math/DivModTests.java assumes ArithmeticException message

[Krystal Mo]

Forgot to mention: the two runs of the test in the last mail were 
examples of test failures before the fix. They would run fine after the fix.

- Kris

On 12/01/2012 02:48 AM, Krystal Mo wrote:
> Hi all,
>
> Could I get a couple of review for this small change, please?
> And could someone from the JDK side sponsor this change?
>
> Bug: https://jbs.oracle.com/bugs/browse/JDK-8004066
> Webrev: http://cr.openjdk.java.net/~kmo/8004066/webrev.00/
>
> The DivModTest introduced in JDK-6282196 [1] checks the contents of 
> the exception message, but that message isn't specified in JavaDoc and 
> thus may vary between VM implementations (or even in the same VM).
>
> The issue has affected HotSpot Server VM in nightlies, and the Shark 
> VM. As OpenJDK library code may receive broader adoption in the 
> future, this issue may affect other VM implementations in the future 
> as well.
>
> (Details:
> The HotSpot Server Compiler may recompile hot throw sites to throw a 
> preallocated exception object, with null exception message, leading to 
> a NPE in the test;
> The bytecode interpreter in Zero/Shark VM throws the 
> ArithmeticException with "/ by long zero" for ldiv, which is different 
> from normal HotSpot behavior (which is expected by the test) where the 
> exception message is "/ by zero".)
>
> This change relaxes the test so that it's more lenient and less 
> sensitive to the error message produced by the VM.
> I don't think there's a good/reliable way of verifying whether an 
> ArithmeticException came from "division by zero", checking the type 
> should be enough for now.
>
> Tested with the failing nightly test case and jprt.
>
> $ java -Xcomp -showversion -XX:DefaultMaxRAMFraction=8 
> -XX:-TieredCompilation -XX:CompileThreshold=100 
> -XX:+UnlockExperimentalVMOptions -XX:+IgnoreUnrecognizedVMOptions 
> -XX:+AggressiveOpts -XX:+IgnoreUnrecognizedVMOptions 
> -XX:-UseCompressedOops DivModTests
> java version "1.8.0-ea"
> Java(TM) SE Runtime Environment (build 1.8.0-ea-b65)
> Java HotSpot(TM) 64-Bit Server VM (build 25.0-b11-internal-fastdebug, 
> compiled mode)
>
> Exception in thread "main" java.lang.NullPointerException
>     at DivModTests.resultEquals(DivModTests.java:390)
>     at DivModTests.testIntFloorMod(DivModTests.java:126)
>     at DivModTests.testIntFloorDivMod(DivModTests.java:103)
>     at DivModTests.testIntFloorDivMod(DivModTests.java:68)
>     at DivModTests.main(DivModTests.java:45)
>
>
> Description from the bug report:
> ~/jdk/test/java/lang/Math$ java -Xint -showversion DivModTests
> java version "1.8.0-ea"
> Java(TM) SE Runtime Environment (build 1.8.0-ea-b65)
> OpenJDK 64-Bit Shark VM (build 25.0-b11-internal, interpreted mode)
>
> FAIL: long Math.floorDiv(4, 0) = java.lang.ArithmeticException: / by 
> long zero; expected java.lang.ArithmeticException: / by zero
> FAIL: long StrictMath.floorDiv(4, 0) = java.lang.ArithmeticException: 
> / by long zero; expected java.lang.ArithmeticException: / by zero
> FAIL: long Math.floorMod(4, 0) = java.lang.ArithmeticException: / by 
> long zero; expected java.lang.ArithmeticException: / by zero
> FAIL: long StrictMath.floorMod(4, 0) = java.lang.ArithmeticException: 
> / by long zero; expected java.lang.ArithmeticException: / by zero
> Exception in thread "main" java.lang.RuntimeException: 4 errors found 
> in DivMod methods.
> at DivModTests.main(DivModTests.java:49)
>
> Regards,
> Kris
>
> [1]: https://jbs.oracle.com/bugs/browse/JDK-6282196