Anton Pryamostanov created GROOVY-8880:
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Summary: Traits - static/instance init blocks
Key: GROOVY-8880
URL: https://issues.apache.org/jira/browse/GROOVY-8880
Project: Groovy
Issue Type: Improvement
Components: Compiler, groovy-runtime
Affects Versions: 2.5.2
Reporter: Anton Pryamostanov
Let's consider the below examples of Traits with Init blocks:
*Instance init block:*
{code}
trait InstanceTrait {
{
System.out.println("Instance init")
}
}
class InstanceTraitClass implements InstanceTrait {
}
new InstanceTraitClass()
{code}
This gives the below compilation exception:
{code:java}
General error during class generation: NPE while processing
script1542098577743.groovy
groovy.lang.GroovyRuntimeException: NPE while processing
script1542098577743.groovy
at
org.codehaus.groovy.classgen.AsmClassGenerator.visitClass(AsmClassGenerator.java:2
at
org.codehaus.groovy.control.CompilationUnit$17.call(CompilationUnit.java:8
at
org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:10
at
org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:6
at
org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:5
at
org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:5
at org.codehaus.groovy.control.CompilationUnit$compile$1.call(Unknown Sour
at
org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:
at
org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:1
at
org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:1
at
groovy.inspect.swingui.AstNodeToScriptAdapter.compileToScript(AstNodeToScriptAdapter.groovy:
at
groovy.inspect.swingui.AstNodeToScriptAdapter$compileToScript.call(Unknown Sour
at
org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:
at
org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:1
at
groovy.inspect.swingui.AstBrowser$_decompile_closure6.doCall(AstBrowser.groovy:3
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Meth
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:
at java.lang.reflect.Method.invoke(Method.java:4
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:3
at
org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:2
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:10
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:10
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:10
at groovy.lang.Closure.call(Closure.java:4
at groovy.lang.Closure.call(Closure.java:4
at groovy.lang.Closure.run(Closure.java:4
at java.lang.Thread.run(Thread.java:7
Caused by: java.lang.NullPointerException
at
org.codehaus.groovy.classgen.asm.CallSiteWriter.prepareCallSite(CallSiteWriter.java:2
at
org.codehaus.groovy.classgen.asm.CallSiteWriter.prepareSiteAndReceiver(CallSiteWriter.java:2
at
org.codehaus.groovy.classgen.asm.CallSiteWriter.prepareSiteAndReceiver(CallSiteWriter.java:2
at
org.codehaus.groovy.classgen.asm.CallSiteWriter.makeCallSite(CallSiteWriter.java:2
at
org.codehaus.groovy.classgen.asm.InvocationWriter.makeCachedCall(InvocationWriter.java:3
at
org.codehaus.groovy.classgen.asm.InvocationWriter.makeCall(InvocationWriter.java:3
at
org.codehaus.groovy.classgen.asm.InvocationWriter.makeCall(InvocationWriter.java:1
at
org.codehaus.groovy.classgen.asm.InvocationWriter.makeInvokeMethodCall(InvocationWriter.java:
at
org.codehaus.groovy.classgen.asm.InvocationWriter.writeInvokeMethod(InvocationWriter.java:4
at
org.codehaus.groovy.classgen.AsmClassGenerator.visitMethodCallExpression(AsmClassGenerator.java:7
at
org.codehaus.groovy.ast.expr.MethodCallExpression.visit(MethodCallExpression.java:
at
org.codehaus.groovy.classgen.asm.StatementWriter.writeExpressionStatement(StatementWriter.java:6
at
org.codehaus.groovy.classgen.asm.OptimizingStatementWriter.writeExpressionStatement(OptimizingStatementWriter.java:3
at
org.codehaus.groovy.classgen.AsmClassGenerator.visitExpressionStatement(AsmClassGenerator.java:6
at
org.codehaus.groovy.ast.stmt.ExpressionStatement.visit(ExpressionStatement.java:
at
org.ehaus.groovy.classgen.asm.StatementWriter.writeBlockStatement(StatementWriter.java:85)
at
org.codehaus.groovy.classgen.asm.OptimizingStatementWriter.writeBlockStatement(OptimizingStatementWriter.java:1
at
org.codehaus.groovy.classgen.AsmClassGenerator.visitBlockStatement(AsmClassGenerator.java:5
at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:
at
org.codehaus.groovy.classgen.asm.StatementWriter.writeBlockStatement(StatementWriter.java:
at
org.codehaus.groovy.classgen.asm.OptimizingStatementWriter.writeBlockStatement(OptimizingStatementWriter.java:1
at
org.codehaus.groovy.classgen.AsmClassGenerator.visitBlockStatement(AsmClassGenerator.java:5
at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:
at
org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitObjectInitializerStatements(ClassCodeVisitorSupport.java:
at
org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:
at
org.codehaus.groovy.classgen.AsmClassGenerator.visitClass(AsmClassGenerator.java:2
... 28 m
{code}
*Static init block:*
{code}
trait StaticTrait {
static {
System.out.println("Static init")
}
}
class StaticTraitClass implements StaticTrait {
}
new StaticTraitClass()
{code}
This compiles but gives below runtime exception:
{code:java}
java.lang.ExceptionInInitializerError
at ConsoleScript278.run(ConsoleScript278:12)
Caused by: groovy.lang.MissingMethodException: No signature of method: static
StaticTrait.<clinit>() is applicable for argument types: (java.lang.Class)
values: [class StaticTraitClass]
at StaticTrait$Trait$Helper.$static_methodMissing(ConsoleScript278)
at StaticTraitClass.<clinit>(ConsoleScript278)
... 1 more
{code}
*Expected enhancement*:
- If it is easy to implement - please add support for above init blocks into
traits.
Use case: adding initialization traits to classes.
- If it is difficult to implement - please add user-friendly error message for
both cases and take decision not to support init blocks in Groovy traits.
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