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  1. JBRULES
  2. JBRULES-3283

Concurrency issue: Invalid bytecode generated by KnowledgeBuilder.add()

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      Perform parallel operation of adding resources to different knowledgebuilders:

      public static KnowledgeBase readKnowledgeBase(final String resource) throws Exception
    {
        final Reader source;
        final String fileName = "/" + resource + ".drl";

        InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName);
        if (inputStream == null)
        {
            inputStream = new FileInputStream("src/main/resources" + fileName);
        }
        source = new InputStreamReader(inputStream, "UTF-8");

        final Properties props = new Properties();
        props.setProperty("drools.dialect.java.compiler", "JANINO");
        props.setProperty("drools.dialect.java.compiler.lnglevel", "1.6");
        KnowledgeBase result;

        final KnowledgeBuilderConfiguration configuration = KnowledgeBuilderFactory.newKnowledgeBuilderConfiguration(props, RuleUtil.class.getClassLoader());
        final KnowledgeBuilder builder = KnowledgeBuilderFactory.newKnowledgeBuilder(configuration);

        Resource newReaderResource = ResourceFactory.newReaderResource(source);
        //synchronized (RuleUtil.class)
        {
            builder.add(newReaderResource, ResourceType.DRL);
        }
        result = builder.newKnowledgeBase();

        return result;
    }
      Show
      Perform parallel operation of adding resources to different knowledgebuilders: public static KnowledgeBase readKnowledgeBase( final String resource) throws Exception { final Reader source; final String fileName = "/" + resource + ".drl" ; InputStream inputStream = Thread .currentThread().getContextClassLoader().getResourceAsStream(fileName); if (inputStream == null ) { inputStream = new FileInputStream( "src/main/resources" + fileName); } source = new InputStreamReader(inputStream, "UTF-8" ); final Properties props = new Properties(); props.setProperty( "drools.dialect.java.compiler" , "JANINO" ); props.setProperty( "drools.dialect.java.compiler.lnglevel" , "1.6" ); KnowledgeBase result; final KnowledgeBuilderConfiguration configuration = KnowledgeBuilderFactory.newKnowledgeBuilderConfiguration(props, RuleUtil. class. getClassLoader()); final KnowledgeBuilder builder = KnowledgeBuilderFactory.newKnowledgeBuilder(configuration); Resource newReaderResource = ResourceFactory.newReaderResource(source); // synchronized (RuleUtil.class) { builder.add(newReaderResource, ResourceType.DRL); } result = builder.newKnowledgeBase(); return result; }
    • Hide

      Synchronize access of KnowledgeBuilder.add()

      Show
      Synchronize access of KnowledgeBuilder.add()

    Description

      Since Drools 5.3.0.CR1 concurrent creation of different knowledgebases from filesystem DRL rule definition leads to illegal bytecode.
      Reproduceable with Janino and eclipse compiler.

      I have a maven based test project which executes the unit tests in parallel, this is the result:

      runFirst(de.trion.drools53.TwoTest): -1
  runFirst(de.trion.drools53.FourTest): (class: de/trion/drools53/Rule_When_a_user_is_young__print_his_name_DefaultConsequenceInvoker, method: equals signature: (Ljava/lang/Object;)Z) Expecting to find integer on stack
  runSecond(de.trion.drools53.FourTest): (class: de/trion/drools53/Rule_When_a_user_is_young__print_his_name_DefaultConsequenceInvoker, method: equals signature: (Ljava/lang/Object;)Z) Expecting to find integer on stack
  runFirst(de.trion.drools53.OneTest): (class: de/trion/drools53/Rule_When_a_user_is_young__print_his_name_DefaultConsequenceInvoker, method: equals signature: (Ljava/lang/Object;)Z) Expecting to find integer on stack
  runFirst(de.trion.drools53.ThreeTest): (class: de/trion/drools53/Rule_When_a_user_is_young__print_his_name_DefaultConsequenceInvoker, method: equals signature: (Ljava/lang/Object;)Z) Incompatible object argument for function call
  runSecond(de.trion.drools53.ThreeTest): (class: de/trion/drools53/Rule_When_there_is_god__the_light_always_shines_DefaultConsequenceInvoker, method: equals signature: (Ljava/lang/Object;)Z) Unable to pop operand off an empty stack

      Workaround: synchronize access
      Not affected: Drools 5.3.0.Beta

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          is duplicated by

          Bug - A problem that impairs or prevents the functions of the product. JBRULES-3657 Eval bytecode not correctly generated

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Resolved
          relates to

          Quality Risk - A potential bug. JBRULES-2380 KnowledgeBuilderImpl.add(...) throws org.mvel2.CompileException when executed concurrently for the same resource

          • Major - To be worked after higher priority work items are addressed. When the severity is high and the effort to change it is low to moderate, this term is chosen. Issues in this category likely have an existing workaround but implementation or execution may be non-trivial.
          • Closed

          Activity

            People

              mfusco@redhat.com Mario Fusco
              evrflx Thomas Kruse (Inactive)
              Archiver:
              rhn-support-ceverson Clark Everson

              Dates

                Created:
                Updated:
                Resolved:
                Archived:

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