[jira] [Updated] (GROOVY-8096) setScriptBaseClass with Java base class breaks @Field initialization from Binding due to generated call to wrong constructor

["Christoffer Hammarström (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GROOVY-8096?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Christoffer Hammarström updated GROOVY-8096:
--------------------------------------------
    Summary: setScriptBaseClass with Java base class breaks @Field initialization from Binding due to generated call to wrong constructor  (was: setScriptBaseClass with Java base class breaks @Field initialization from Binding due to wrong constructor)

> setScriptBaseClass with Java base class breaks @Field initialization from Binding due to generated call to wrong constructor
> ----------------------------------------------------------------------------------------------------------------------------
>
>                 Key: GROOVY-8096
>                 URL: https://issues.apache.org/jira/browse/GROOVY-8096
>             Project: Groovy
>          Issue Type: Bug
>          Components: Compiler, GroovyScriptEngine
>    Affects Versions: 2.4.8
>            Reporter: Christoffer Hammarström
>            Priority: Major
>              Labels: test
>
> I created a pull request on GitHub with a failing test showing the problem: [https://github.com/apache/groovy/pull/502]
> This test fails because {{ModuleNode.createStatementsClass()}} calls {{.getSuperClass().getDeclaredConstructor(SCRIPT_CONTEXT_CTOR)}} and gets {{null}} back, though the constructor does exist!
> {{ModuleNode.setScriptBaseClassFromConfig(ClassNode)}}
>  calls {{.setSuperClass(ClassHelper.make(baseClassName))}} on the {{scriptDummy ClassNode}}.
> The {{ClassNode}} created for this script's base class has {{.lazyInitDone = true}} and {{.constructors = null}}
> {{ModuleNode.createStatementsClass()}} calls {{.getSuperClass().getDeclaredConstructor(SCRIPT_CONTEXT_CTOR)}}
> Then {{ClassNode.constructors}} is set to an empty ArrayList in {{ClassNode.getDeclaredConstructors()}}, insteaf of looking them up from the Java class.
> The script constructor is then generated in {{ModuleNode.createStatementsClass()}} as:
> *BROKEN BEHAVIOUR*
> {code:java}
>      Constructor(Binding context) {
>          super();             // Fields are initialized after the call to super()
>                               // Fields are initialized here with new Binding() instead of context
>          setBinding(context); // This is too late, fields are initialized after super(), before this call to setBinding
>      }
> {code}
> instead of
> *EXPECTED BEHAVIOUR*
> {code:java}
>      Constructor(Binding context) {
>          super(context); // Fields are initialized after the call to super(context)
>      }
> {code}
> We're calling the default constructor in the base class with {{super()}}, instead of passing along the {{Binding context}} with {{super(context)}}
> This breaks initialization of Fields that depend on the {{Binding context}}, because Fields are initialized between the call to {{super()}} and the {{setBinding(context)}}: [http://stackoverflow.com/a/14806340/233014]
> This leads to {{MissingPropertyException}} because we're trying to look up variables from the {{new Binding()}} created in the default constructor, instead of the binding we passed in.
> For convenience, here is the failing test:
> {code:java|title=GroovyShellTest2.groovy}
>     void testBindingsInFieldInitializersWithConfigJavaBaseScript() {
>         def config = new org.codehaus.groovy.control.CompilerConfiguration()
>         config.scriptBaseClass = BindingScript.class.name
>         def shell = new GroovyShell(config);
>         def scriptText = '''
>         @groovy.transform.Field def script_args = getProperty('args')    // Will get MissingPropertyException here because this @Field is initialized after the call to super(), before the call to setBinding in the script constructor
>         assert script_args[0] == 'Hello Groovy'
>         script_args[0]
> '''
>         def arg0 = 'Hello Groovy'
>         def result = shell.run scriptText, 'TestBindingsInFieldInitializersWithConfigJavaBaseScript.groovy', [arg0]
>         assert result == arg0
>     }
> {code}
> and the Java script base class:
> {code:java|title=BindingScript.java}
> package groovy.lang;
> /**
>  * A Script which requires a Binding passed in the constructor and disallows calling the default constructor.
>  */
> public abstract class BindingScript extends Script {
>     // Making the default constructor private instead gives IllegalAccessError
>     // Removing the default constructor instead gives NoSuchMethodError
>     // Removing both constructors just calls to the default constructor in groovy.lang.Script giving MissingPropertyException on field initialization
>     protected BindingScript() {
>         // This constructor erroneously gets called instead of the other one
>     }
>     
>     protected BindingScript(Binding binding) {
>         super(binding);
>         // This is the constructor that should have been called, because then the binding would have been passed in the above call, before @Fields are initialised.
>     }
> }
> {code}



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