When we build a rule written in MVEL dialect like (*1) with executable model disabled and run the rule using the test code like (*2), MVEL syntax error like (*e1) or (*e2) sometimes occurs though the rule normally does not cause errors. The test code simultaneously executes multiple jobs each of which creates a new KieSession, inserts objects and calls fireAllRules.
This issue is similar to RHDM-1629. However, from the stack trace of the exception (*e1) and (*e2), it is different in the way that it does not occur inside MvelConstraint#evaluate but occurs inside MVELConsequence#evaluate (*e1-1) and (*e2-1).
(*1)
package com.example.reproducer
dialect "mvel"
rule "rule_mt_2a"
when
$bus : Bus( $title : "POWER PLANT" )
then
System.out.println("***** Action of rule_mt_2a");
System.out.println("***** artist: " + $bus.karaoke.dvd[$title].artist);
end
(*2) Test code (In the actual code in the reproducer, java.util.concurrent.Semaphore is used for making reproducibility higher.)
KieServices kServices = KieServices.Factory.get();
KieContainer kContainer = kServices.getKieClasspathContainer();
int THREADS = 32;
int REQUESTS = 10000;
ExecutorService pool = Executors.newFixedThreadPool(THREADS);
List<Future<?>> fs = new ArrayList<>();
System.out.println("***** start threads");
for (int i = 0; i < REQUESTS; i++) {
fs.add(pool.submit(new Runnable() {
public void run() {
KieSession kSession = kContainer.newKieSession("session1");
Bus bus1 = new Bus("red", 30);
bus1.getKaraoke().getDvd().put("POWER PLANT", new Album("POWER PLANT", "GAMMA RAY"));
bus1.getKaraoke().getDvd().put("Somewhere Out In Space", new Album("Somewhere Out In Space", "GAMMA RAY"));
kSession.insert(bus1);
try {
kSession.fireAllRules();
} catch (Exception e) {
e.printStackTrace();
}
kSession.dispose();
kSession.destroy();
}
}));
}
(*e1)
Exception executing consequence for rule "rule_mt_2a" in com.example.reproducer: [Error: unable to resolve method using strict-mode: java.lang.Object.artist()]
[Near : {... .out.println("***** artist: " + $bus.karaoke.dvd[$ ....}]
^
[Line: 2, Column: 35]
at org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.core.common.DefaultAgenda.handleException(DefaultAgenda.java:1306)
at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:455)
at org.drools.core.phreak.RuleExecutor.fireActivation(RuleExecutor.java:395)
at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:151)
at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:103)
at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:33)
at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)
at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1116)
at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1063)
at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1055)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1346)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1337)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1321)
at com.example.reproducer.DroolsTest$1.run(DroolsTest.java:73)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: [Error: unable to resolve method using strict-mode: java.lang.Object.artist()]
[Near : {... .out.println("***** artist: " + $bus.karaoke.dvd[$ ....}]
^
[Line: 2, Column: 35]
at org.mvel2.compiler.PropertyVerifier.getMethod(PropertyVerifier.java:581)
at org.mvel2.compiler.PropertyVerifier.getBeanProperty(PropertyVerifier.java:295)
at org.mvel2.compiler.PropertyVerifier.analyze(PropertyVerifier.java:133)
at org.mvel2.compiler.ExpressionCompiler.verify(ExpressionCompiler.java:400)
at org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:259)
at org.mvel2.util.ParseTools.subCompileExpression(ParseTools.java:2118)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:969)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:400)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:167)
at org.mvel2.ast.ASTNode.optimize(ASTNode.java:159)
at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:115)
at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
at org.mvel2.compiler.CompiledExpression.getDirectValue(CompiledExpression.java:123)
at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:119)
at org.mvel2.MVEL.executeExpression(MVEL.java:945)
at org.drools.mvel.expr.MVELConsequence.evaluate(MVELConsequence.java:108) .......... (*e1-1)
at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:448)
... 17 more
(*e2)
Exception executing consequence for rule "rule_mt_2a" in com.example.reproducer: [Error: not a statement, or badly formed structure]
[Near : {... ("***** artist: " + $bus.karaoke.dvd[$title].artis ....}]
^
[Line: 2, Column: 47]
at org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)
at org.drools.core.common.DefaultAgenda.handleException(DefaultAgenda.java:1306)
at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:455)
at org.drools.core.phreak.RuleExecutor.fireActivation(RuleExecutor.java:395)
at org.drools.core.phreak.RuleExecutor.fire(RuleExecutor.java:151)
at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:103)
at org.drools.core.concurrent.AbstractRuleEvaluator.internalEvaluateAndFire(AbstractRuleEvaluator.java:33)
at org.drools.core.concurrent.SequentialRuleEvaluator.evaluateAndFire(SequentialRuleEvaluator.java:43)
at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1116)
at org.drools.core.common.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:1063)
at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1055)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1346)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1337)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1321)
at com.example.reproducer.DroolsTest$1.run(DroolsTest.java:73)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: [Error: not a statement, or badly formed structure]
[Near : {... ("***** artist: " + $bus.karaoke.dvd[$title].artis ....}]
^
[Line: 2, Column: 47]
at org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:312)
at org.mvel2.util.ParseTools.subCompileExpression(ParseTools.java:2118)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.getMethod(ReflectiveAccessorOptimizer.java:969)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.compileGetChain(ReflectiveAccessorOptimizer.java:400)
at org.mvel2.optimizers.impl.refl.ReflectiveAccessorOptimizer.optimizeAccessor(ReflectiveAccessorOptimizer.java:167)
at org.mvel2.ast.ASTNode.optimize(ASTNode.java:159)
at org.mvel2.ast.ASTNode.getReducedValueAccelerated(ASTNode.java:115)
at org.mvel2.MVELRuntime.execute(MVELRuntime.java:85)
at org.mvel2.compiler.CompiledExpression.getDirectValue(CompiledExpression.java:123)
at org.mvel2.compiler.CompiledExpression.getValue(CompiledExpression.java:119)
at org.mvel2.MVEL.executeExpression(MVEL.java:945)
at org.drools.mvel.expr.MVELConsequence.evaluate(MVELConsequence.java:108) .......... (*e2-1)
at org.drools.core.phreak.RuleExecutor.innerFireActivation(RuleExecutor.java:448)
... 17 more
Caused by: java.lang.NullPointerException
at org.mvel2.compiler.PropertyVerifier.getCollectionProperty(PropertyVerifier.java:403)
at org.mvel2.compiler.PropertyVerifier.analyze(PropertyVerifier.java:139)
at org.mvel2.compiler.ExpressionCompiler.verify(ExpressionCompiler.java:400)
at org.mvel2.compiler.ExpressionCompiler._compile(ExpressionCompiler.java:259)
... 29 more
- incorporates
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DROOLS-6432 Calling fireAllRules simultaneously from multiple threads sometimes causes an exception inside MVELConsequence#evaluate.
-
- Closed
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