Optaplanner 7.48迁移至8.3.0时Drools ExpressionTyper异常问题咨询

迁移背景 #

项目从 OptaPlanner 7.48（对应依赖 Drools 7.48 版本）迁移至 OptaPlanner 8.3.0（对应依赖 Drools 7.50 版本）时，原有DRL规则无法正常运行，初步推断问题根源与 Drools 7.50 版本的规则解析逻辑变化相关。

迁移前可正常运行的DRL规则 #

rule "applyHomeTeamConstraints"
  enabled true
    when $f1: ProblemFixture(slot != null, $ht: homeTeam)
         $tu: ProblemSoftConstraint(this memberOf $ht.constraints,
                                  matches($f1.slot.dateTime) )
    then
        scoreHolder.penalize(kcontext, -$tu.getWeight());
end

异常表现 #

上述规则在 OptaPlanner 7.48/Drools 7.48 环境下可正常编译运行，切换到新版本环境后抛出定位信息极度模糊的异常，早期堆栈压缩状态下的报错内容为：

java.lang.IllegalStateException: There is an error in a scoreDrl or scoreDrlFile.
    at uk.me.selwyn_family.league.scheduler.solver.SolverTest.testBuildSeasonSolver(SolverTest.java:47)
Caused by: java.lang.UnsupportedOperationException
    at uk.me.selwyn_family.league.scheduler.solver.SolverTest.testBuildSeasonSolver(SolverTest.java:47)

排查过程 #

• 逐行定位异常后，确认错误实际抛出位置为 org.drools.modelcompiler.builder.generator.expressiontyper.ExpressionTyper 类的第243行，对应源码逻辑为：

  Expression parentLeft = findLeftLeafOfNameExpr(halfPointFreeExpr.getParentNode().orElseThrow(UnsupportedOperationException::new));
  

• 异常触发的直接原因是代码中获取的父节点对象为空，抛出的异常未携带任何规则解析的上下文信息，大幅增加排查成本。
• 临时解决方案：在matches()方法调用前补充this.关键字，即可绕开解析异常，修改后的规则片段为：

  rule "applyHomeTeamConstraints"
    enabled true
      when $f1: ProblemFixture(slot != null, $ht: homeTeam)
           $tu: ProblemSoftConstraint(this memberOf $ht.constraints,
                                    this.matches($f1.slot.dateTime) )
      then
          scoreHolder.penalize(kcontext, -$tu.getWeight());
  end
  

核心待确认问题 #

• 旧版本下不带this.的方法调用写法可正常运行，是否属于旧版本解析的兼容疏漏、本身不符合Drools语法规范，还是Drools 7.50 版本引入的解析bug？
• 该场景下的编译报错信息缺失关键上下文，排查耗时极长，是否能优化错误提示的清晰度，让用户直接定位到规则内的具体语法问题？

关闭堆栈压缩后的完整异常栈 #

java.lang.IllegalStateException: There is an error in a scoreDrl or scoreDrlFile.
    at org.optaplanner.core.impl.score.director.ScoreDirectorFactoryFactory.buildDroolsScoreDirectorFactory(ScoreDirectorFactoryFactory.java:280)
    at org.optaplanner.core.impl.score.director.ScoreDirectorFactoryFactory.decideMultipleScoreDirectorFactories(ScoreDirectorFactoryFactory.java:103)
    at org.optaplanner.core.impl.score.director.ScoreDirectorFactoryFactory.buildScoreDirectorFactory(ScoreDirectorFactoryFactory.java:68)
    at org.optaplanner.core.impl.solver.DefaultSolverFactory.buildScoreDirectorFactory(DefaultSolverFactory.java:116)
    at org.optaplanner.core.impl.solver.DefaultSolverFactory.getScoreDirectorFactory(DefaultSolverFactory.java:73)
    at org.optaplanner.core.api.score.ScoreManager.create(ScoreManager.java:59)
    at uk.me.selwyn_family.league.scheduler.solver.SeasonSolver.<init>(SeasonSolver.java:31)
    at uk.me.selwyn_family.league.scheduler.solver.SolverTest.testBuildSeasonSolver(SolverTest.java:47)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:85)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:696)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:882)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1189)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:124)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:108)
    at org.testng.TestRunner.privateRun(TestRunner.java:767)
    at org.testng.TestRunner.run(TestRunner.java:617)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:348)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:343)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:305)
    at org.testng.SuiteRunner.run(SuiteRunner.java:254)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1149)
    at org.testng.TestNG.run(TestNG.java:1057)
    at org.apache.maven.surefire.testng.TestNGExecutor.run(TestNGExecutor.java:136)
    at org.apache.maven.surefire.testng.TestNGDirectoryTestSuite.executeSingleClass(TestNGDirectoryTestSuite.java:112)
    at org.apache.maven.surefire.testng.TestNGDirectoryTestSuite.execute(TestNGDirectoryTestSuite.java:99)
    at org.apache.maven.surefire.testng.TestNGProvider.invoke(TestNGProvider.java:145)
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:428)
    at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:162)
    at org.apache.maven.surefire.booter.ForkedBooter.run(ForkedBooter.java:562)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:548)
Caused by: java.lang.UnsupportedOperationException
    at java.base/java.util.Optional.orElseThrow(Optional.java:408)
    at org.drools.modelcompiler.builder.generator.expressiontyper.ExpressionTyper.toTypedExpressionRec(ExpressionTyper.java:243)
    at org.drools.modelcompiler.builder.generator.expressiontyper.ExpressionTyper.toTypedExpression(ExpressionTyper.java:153)
    at org.drools.modelcompiler.builder.generator.drlxparse.ConstraintParser.getDrlxParseResult(ConstraintParser.java:174)
    at org.drools.modelcompiler.builder.generator.drlxparse.ConstraintParser.drlxParse(ConstraintParser.java:104)
    at org.drools.modelcompiler.builder.generator.visitor.pattern.PatternDSL.findAllConstraint(PatternDSL.java:139)
    at org.drools.modelcompiler.builder.generator.visitor.pattern.PatternDSL.buildPattern(PatternDSL.java:241)
    at org.drools.modelcompiler.builder.generator.visitor.ModelGeneratorVisitor.visit(ModelGeneratorVisitor.java:145)
    at org.drools.compiler.lang.descr.PatternDescr.accept(PatternDescr.java:303)
    at org.drools.modelcompiler.builder.generator.visitor.AndVisitor.visit(AndVisitor.java:50)
    at org.drools.modelcompiler.builder.generator.visitor.ModelGeneratorVisitor.visit(ModelGeneratorVisitor.java:86)
    at org.drools.modelcompiler.builder.generator.ModelGenerator.processRule(ModelGenerator.java:187)
    at org.drools.modelcompiler.builder.generator.ModelGenerator.generateModel(ModelGenerator.java:160)
    at org.drools.modelcompiler.builder.ModelBuilderImpl.compileKnowledgePackages(ModelBuilderImpl.java:284)
    at org.drools.modelcompiler.builder.ModelBuilderImpl.buildRules(ModelBuilderImpl.java:220)
    at org.drools.modelcompiler.builder.ModelBuilderImpl.postBuild(ModelBuilderImpl.java:130)
    at org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl.build(CompositeKnowledgeBuilderImpl.java:115)
    at org.drools.compiler.builder.impl.CompositeKnowledgeBuilder.build(CompositeKnowledgeBuilder.java:99)
    at org.drools.compiler.kie.builder.impl.AbstractKieProject.buildKnowledgePackages(AbstractKieProject.java:268)
    at org.drools.compiler.kie.builder.impl.AbstractKieProject.buildKnowledgePackages(AbstractKieProject.java:216)
    at org.drools.compiler.kie.builder.impl.AbstractKieProject.verify(AbstractKieProject.java:80)
    at org.drools.compiler.kie.builder.impl.KieBuilderImpl.buildKieProject(KieBuilderImpl.java:277)
    at org.drools.compiler.kie.builder.impl.KieBuilderImpl.buildAll(KieBuilderImpl.java:245)
    at org.drools.compiler.kie.builder.impl.KieBuilderImpl.buildAll(KieBuilderImpl.java:202)
    at org.kie.internal.utils.KieHelper.getKieContainer(KieHelper.java:100)
    at org.kie.internal.utils.KieHelper.build(KieHelper.java:82)
    at org.optaplanner.core.impl.score.director.ScoreDirectorFactoryFactory.buildDroolsScoreDirectorFactory(ScoreDirectorFactoryFactory.java:272)
    ... 36 more

内容的提问来源于stack exchange，提问作者Chris Selwyn