Initialization of @Param's in nested @State classes

[Gleb Smirnov]

Hi All,

Given the following test case:

public class NestedStateBenchmark {

    @State(Scope.Benchmark)
    public static class NestedState {
        @Param({"0", "1"})
        public int foo;
    }

    @State(Scope.Thread)
    public static class OuterState {
        public int bar;

        @Setup
        public void setup(NestedState nestedState) {
            this.bar = -nestedState.foo;
        }
    }

    @Benchmark
    public int measure(OuterState state) {
        return state.bar;
    }
}

One would expect the `measure` method to be returning 0 or 1, with respect
to
the param `foo`.

However, what actually happens is the benchmark crashing with the following
exception:

java.lang.IllegalStateException: The value for the parameter "foo" is not
set.
        at
org.openjdk.jmh.runner.InfraControlL2.getParam(InfraControl.java:190)
        at
org.openjdk.jmh.runner.InfraControl.getParam(InfraControl.java:39)
        at
generated.NestedStateBenchmark_measure._jmh_tryInit_f_nestedstate3_G(NestedStateBenchmark_measure.java:331)
        at
generated.NestedStateBenchmark_measure.measure_Throughput(NestedStateBenchmark_measure.java:57)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at
org.openjdk.jmh.runner.LoopBenchmarkHandler$BenchmarkTask.call(LoopBenchmarkHandler.java:199)
        at
org.openjdk.jmh.runner.LoopBenchmarkHandler$BenchmarkTask.call(LoopBenchmarkHandler.java:181)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown
Source)
        at java.lang.Thread.run(Unknown Source)

This is a bug, a person familiar with the matter said
(https://twitter.com/shipilev/status/533565238407618560)

Reproducible with JMH 1.3.

--
Gleb