RFR: 8289400: Improve com/sun/jdi/TestScaffold error reporting

[Alex Menkov]

On Thu, 1 Sep 2022 19:09:25 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

> com/sun/jdi tests report errors by calling TestScaffold.failure(msg), which prints the failure message and sets the testFailed flag. At some later point the failure is detected and an exception is thrown. The end result is the exception has just has a vanilla message that says something like "TestXXX failed", and the backtrace is not indicative of where the failure occurred. If you have tools that search logs looking for exceptions to determine the reason for the failure, you likely won't find any. Here's an example: 
> 
> [2ms] run args: [SuspendAfterDeathTarg]
> [514ms] FAILED: got Breakpoint event before ThreadDeath event.
> java.lang.Exception: SuspendAfterDeath: failed
> at SuspendAfterDeath.runTests(SuspendAfterDeath.java:110)
> at TestScaffold.startTests(TestScaffold.java:432)
> at SuspendAfterDeath.main(SuspendAfterDeath.java:47)
> at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
> at java.base/java.lang.reflect.Method.invoke(Method.java:578)
> at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
> at java.base/java.lang.Thread.run(Thread.java:1589)
> 
> So the reason for the failure is clear (the "FAILED" message), but its stack trace is missing and the reason is not included in the exception message that is printed much later on. This PR adds printing of the stack trace at the time of the failure.

test/jdk/com/sun/jdi/TestScaffold.java line 457:

> 455:         println(str);
> 456:         StackTraceElement[] trace = Thread.currentThread().getStackTrace();
> 457:         for (StackTraceElement traceElement : trace)

Please add curly braces around the cycle body

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PR: https://git.openjdk.org/jdk/pull/10127