ant: calling antcall from <script> throws a java.lang.NullPointerException - ant

Question

In the ant 1.8.2 build system, I am having a javascript that rely on an <antcall/>. That causes me a java.lang.NullPointerException which points to antcall.
Script:
<project default="main">
<target name="main">
<script language="javascript"> <![CDATA[
task = project.createTask( 'macro' );
task.execute();
]]></script>
</target>
<macrodef name="macro">
<sequential>
<antcall target="antcall" />
</sequential>
</macrodef>
<target name="antcall">
<echo>[antcall] succeed</echo>
</target>
</project>
build.xml:11: java.lang.NullPointerException( #3 ... ). The stacktrace just talk about RhinoScriptEngine, not sure that is any helpful
at com.sun.script.javascript.RhinoScriptEngine.eval(RhinoScriptEngine.java:153)
at com.sun.script.javascript.RhinoScriptEngine.eval(RhinoScriptEngine.java:167)
at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:247)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.tools.ant.util.ReflectUtil.invoke(ReflectUtil.java:108)
at org.apache.tools.ant.util.ReflectWrapper.invoke(ReflectWrapper.java:81)
at org.apache.tools.ant.util.optional.JavaxScriptRunner.evaluateScript(JavaxScriptRunner.java:103)
at org.apache.tools.ant.util.optional.JavaxScriptRunner.executeScript(JavaxScriptRunner.java:67)
at org.apache.tools.ant.taskdefs.optional.Script.execute(Script.java:52)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:291)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
at org.apache.tools.ant.Task.perform(Task.java:348)
at org.apache.tools.ant.Target.execute(Target.java:390)
at org.apache.tools.ant.Target.performTasks(Target.java:411)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1399)
at org.apache.tools.ant.Project.executeTarget(Project.java:1368)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
at org.apache.tools.ant.Project.executeTargets(Project.java:1251)
at org.apache.tools.ant.Main.runBuild(Main.java:809)
at org.apache.tools.ant.Main.startAnt(Main.java:217)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:280)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:109)
My questions are:
- can someone reproduce that issue?
- Am I doing something obviously wrong?
- Any ant guru around to assist me :-)

Answer 1

I found a bug report in Groovy detailing a similar issue http://jira.codehaus.org/browse/GROOVY-1506 . The attached patch by Andreas Sahlbach fixed the groovy issue by assigning an owner to a newly created task.
So I have gone ahead and added:
task.setOwningTarget( self.getOwningTarget() );
That fixed the issue. I have put the original script and the fixed one in gist 3636007 so other people can play with.
Final script is below:
<project default="main">
<target name="main">
<script language="javascript"> <![CDATA[
task = project.createTask( 'macro' );
if( task.getOwningTarget() == null ) {
task.log( "Assigning an owner ..." );
task.setOwningTarget( self.getOwningTarget() );
task.log( "Task: " + task.getOwningTarget() );
}
try {
task.execute();
} catch(err) {
task.log( "Execution error: " + err.message );
}
]]></script>
</target>
<macrodef name="macro">
<sequential>
<antcall target="antcall" />
</sequential>
</macrodef>
<target name="antcall">
<echo>[antcall] succeed</echo>
</target>
</project>
The resulting execution is:
$ ant
Buildfile: /Users/amusso/ant/bug/build.xml
main:
[macro] Assigning an owner ...
[macro] Task: main
antcall:
[echo] [antcall] succeed
BUILD SUCCESSFUL
Total time: 0 seconds
\O/