Use HewlettPackard/kraal to prevent "Non-reducible loop"

Use Kraal to prevent GraalVM native-image from failing with "Non-reducible loop".

oracle/graal#366
https://github.com/HewlettPackard/kraal

Without Kraal, here is the native-image's stacktrace:

	Error: Non-reducible loop
	Call path from entry point to pullpitok.AppKt$main$1.invokeSuspend(Object):
		at pullpitok.AppKt$main$1.invokeSuspend(App.kt)
		at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:32)
		at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:285)
		at java.lang.Shutdown.runHooks(Shutdown.java:123)
		at java.lang.Shutdown.sequence(Shutdown.java:167)
		at java.lang.Shutdown.shutdown(Shutdown.java:234)
		at com.oracle.svm.core.jdk.RuntimeSupport.shutdown(RuntimeSupport.java:181)
		at com.oracle.svm.core.JavaMainWrapper.run(JavaMainWrapper.java:177)
		at com.oracle.svm.core.code.IsolateEnterStub.JavaMainWrapper_run_5087f5482cc9a6abc971913ece43acb471d2631b(generated:0)
	Original exception that caused the problem: org.graalvm.compiler.core.common.PermanentBailoutException: Non-reducible loop
		at org.graalvm.compiler.java.BciBlockMapping.computeBlockOrder(BciBlockMapping.java:882)
		at org.graalvm.compiler.java.BciBlockMapping.build(BciBlockMapping.java:527)
		at org.graalvm.compiler.java.BciBlockMapping.create(BciBlockMapping.java:1109)
		at org.graalvm.compiler.java.BytecodeParser.build(BytecodeParser.java:806)
		at org.graalvm.compiler.java.BytecodeParser.buildRootMethod(BytecodeParser.java:784)
		at org.graalvm.compiler.java.GraphBuilderPhase$Instance.run(GraphBuilderPhase.java:95)
		at org.graalvm.compiler.phases.Phase.run(Phase.java:49)
		at org.graalvm.compiler.phases.BasePhase.apply(BasePhase.java:197)
		at org.graalvm.compiler.phases.Phase.apply(Phase.java:42)
		at org.graalvm.compiler.phases.Phase.apply(Phase.java:38)
		at com.oracle.graal.pointsto.flow.MethodTypeFlowBuilder.parse(MethodTypeFlowBuilder.java:205)
		at com.oracle.graal.pointsto.flow.MethodTypeFlowBuilder.apply(MethodTypeFlowBuilder.java:324)
		at com.oracle.graal.pointsto.flow.MethodTypeFlow.doParse(MethodTypeFlow.java:310)
		at com.oracle.graal.pointsto.flow.MethodTypeFlow.ensureParsed(MethodTypeFlow.java:300)
		at com.oracle.graal.pointsto.flow.MethodTypeFlow.addContext(MethodTypeFlow.java:107)
		at com.oracle.graal.pointsto.flow.SpecialInvokeTypeFlow.onObservedUpdate(InvokeTypeFlow.java:421)
		at com.oracle.graal.pointsto.flow.TypeFlow.notifyObservers(TypeFlow.java:347)
		at com.oracle.graal.pointsto.flow.TypeFlow.update(TypeFlow.java:389)
		at com.oracle.graal.pointsto.BigBang$2.run(BigBang.java:508)
		at com.oracle.graal.pointsto.util.CompletionExecutor.lambda$execute$0(CompletionExecutor.java:174)
		at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402)
		at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
		at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
		at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
		at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)

build.gradle.kts

@@ -1,12 +1,12 @@
-import org.jetbrains.kotlin.gradle.dsl.KotlinCompile
+import org.gradle.jvm.tasks.Jar
 
 plugins {
     val kotlinVersion = "1.3.20"
     id("org.jetbrains.kotlin.jvm").version(kotlinVersion)
     id("com.adarshr.test-logger").version("1.6.0")
     id("se.patrikerdes.use-latest-versions") version "0.2.7"
     id("com.github.ben-manes.versions") version "0.20.0"
-    id("com.github.johnrengelman.shadow") version "4.0.4"
+    id("com.hpe.kraal") version "0.0.14"
     application
 }
 
@@ -32,10 +32,19 @@ application {
     mainClassName = "pullpitok.AppKt"
 }
 
-shadow {
-    applicationDistribution.from("src/dist")
+val fatjar by tasks.creating(Jar::class) {
+    from(kraal.outputZipTrees) {
+        exclude("META-INF/*.SF")
+        exclude("META-INF/*.DSA")
+        exclude("META-INF/*.RSA")
+    }
+    manifest {
+        attributes("Main-Class" to application.mainClassName)
+    }
+    destinationDir = project.buildDir.resolve("fatjar")
+    archiveName = "pullpitok.jar"
 }
 
-tasks.shadowJar {
-    minimize()
+tasks.named("assemble").configure {
+    dependsOn(fatjar)
 }

generate-executable.sh

@@ -4,9 +4,9 @@
 set -e
 
 echo "Build nicokosi/pullpitoK JAR file:"
-./gradlew shadowJar
+./gradlew assemble
 
-echo "Build nicokosi/ipullpitoK's executable from JAR via GraalVM:"
+echo "Build nicokosi/pullpitoK's executable from JAR via GraalVM:"
 graalvmDockerImage="oracle/graalvm-ce:1.0.0-rc12"
 docker pull ${graalvmDockerImage}
 docker run \
@@ -15,7 +15,9 @@ docker run \
     --volume $(pwd):/app \
     ${graalvmDockerImage} \
     sh -c "native-image \
-            -jar /app/build/libs/pullpitoK-all.jar \
+            --static \
+            --report-unsupported-elements-at-runtime \
+            -jar /app/build/fatjar/pullpitok.jar \
             pullpitoK && \
         echo ' => Check the executable: ' && ./pullpitoK || \
-        echo ' => Copy it to current directory: ' && cp pullpitoK /app/"
+        echo ' => Copy it to current directory: ' && cp ./pullpitoK /app/"