Ant antcall a target that defines a property

Question

In Ant I want to define a target (called A) that define a property and antcall it from another target (called B). I want that the target B, after antcalling the target A, can access the property defined in the target A.

For example:

<target name="B">
    <antcall target="A" inheritAll="true" inheritRefs="true" />
    <echo>${myprop}</echo>
</target>
<target name="A">
    <property name="myprop" value="myvalue" />
</target>

However it doesn't work and <echo>${myprop}</echo> doesn't print myvalue (I think because the property myprop isn't defined in B).

Is there any way to do that?

Solution 1

According to the Apache Ant FAQ:

    <target name="cond" depends="cond-if"/>

    <target name="cond-if" if="prop1">
      <antcall target="cond-if-2"/>
    </target>

    <target name="cond-if-2" if="prop2">
      <antcall target="cond-if-3"/>
    </target>

    <target name="cond-if-3" unless="prop3">
      <echo message="yes"/>
    </target>

Note: <antcall> tasks do not pass property changes back up to the environment they were called from, so you wouldn't be able to, for example, set a result property in the cond-if-3 target, then do <echo message="result is ${result}"/> in the cond target.

In this respect, it is impossible to do what you want using antcall.

========== edit ===========

Try antcallback: AntCallBack is identical to the standard 'antcall' task, except that it allows properties set in the called target to be available in the calling target.
http://antelope.tigris.org/nonav/docs/manual/bk03ch20.html

Sample code pasted from the above page:

    <target name="testCallback" description="Test CallBack">
        <taskdef name="antcallback" classname="ise.antelope.tasks.AntCallBack" classpath="${antelope.home}/build" />
        <antcallback target="-testcb" return="a, b"/>
        <echo>a = ${a}</echo>
        <echo>b = ${b}</echo>
    </target>

    <target name="-testcb">
        <property name="a" value="A"/>
        <property name="b" value="B"/>
    </target>

Solution 2

Another approach is to refactor your targets into macros. You are trying to use targets like functions and they are just not intended to be used that way. I typically write the bulk of my logic as macros, so that I can compose it more easily into more complicated macros. Then I write simple wrapper targets for the command-line entry points that I need.

Solution 3

Rather than using <antcall>, why not just have target B depend on target A?

<target name="B" depends="A">
    <echo>${myprop}</echo>
</target>
<target name="A">
    <property name="myprop" value="myvalue" />
</target>

Comments

[SOUser]

That is not what OP wants. He wants to define the property in target A, and echo it in target B. Here, you define it in A and echo it in A.

[alem0lars]

Thanks. It was the issue. How do you implement that behaviour in a different way? I mean I would like to divide the logic of a target into subtargets

[rajah9]

Thank you for clarifying the question.

[kevinarpe]

Also, you can try task 'AntCallBack' from Ant-Contrib package: ant-contrib.sourceforge.net/tasks/tasks/index.html

[thekbb]

This is the best approach. ant properties are not variables, they're immutable. an antcall into the same build.xml always smells bad.