We can use the <fail> Ant task to exit the Ant script but this will fail the build.

Sometimes we may have some checking during the build such that it could exit peacefully without build failure in certain cases. So in this case, we can’t use the <fail> Ant task.

A workaround is to use the <if> Ant-contrib task to create a boolean variable and whether continue or not could be determined by checking this boolean in the <target> if attribute.

Here is an example:
build.xml

<project name="test" default="" basedir="." xmlns:artifact="antlib:org.apache.maven.artifact.ant">

  <!-- Load the ant contrib lib -->
  <taskdef resource="net/sf/antcontrib/antcontrib.properties">
    <classpath>
      <pathelement location="${basedir}/ant-lib/ant-contrib-1.0b3.jar"/>
    </classpath>
  </taskdef>

  <target name="step1">
    <echo message="Step 1 is running"/>
    <if>
      <equals arg1="${var1}" arg2="${var2}" />
      <then>
        <property name="continue" value="true"/>
      </then>
      <else>
        <property name="continue" value="false"/>
      </else>
    </if>
  </target>
  
  <target name="step2" depends="step1" if="${continue}">
    <echo message="Step 2 is running"/>
  </target>

</project>

Results:
ant step2

 

ant step2 -Dvar1=abc -Dvar2=def

 

ant step2 -Dvar1=abc -Dvar2=abc

 

As you can see above, step2 will run only if var1 = var2 and all three builds are successful .

Done =)

Reference:

• StackOverflow – Stop ant script without failing build
• <fail> Ant task
• <if> Ant-contrib task