Running Ant exec task without "Result:" output - ant

Question

When the Ant exec task runs a command that completes with non-zero exit status, the exec task outputs the status, such as:
[exec] Result: 1
This is printed without context, and so it is confusing to users.
It is printed even if the exec task is invoked with outputproperty="someproperty" failonerror="false".
I use such an invocation for commands such as grep, where a non-zero output may be the desired, expected result.
Is there a way to suppress the "Result: " output, without making any other changes to the output of the Ant process?

Answer 1

Take a look at the following example which uses JavaScript to disable and restore logging.
build.xml
<project name="ant-exec-intentional-fail" default="run">
<target name="run">
<echo>Show that exec logs "Result: 1" by default...</echo>
<exec executable="sh" failonerror="false">
<arg value="-c"/>
<arg value="exit 1"/>
</exec>
<echo>Disabling logging...</echo>
<script language="javascript"><![CDATA[
var savedLoggers = project.getBuildListeners();
for( var i = 0; i < savedLoggers.length; i++ ) {
var logger = savedLoggers[i];
project.removeBuildListener( logger );
}
project.addReference( "savedLoggers", savedLoggers );
]]></script>
<exec executable="sh" failonerror="false" resultproperty="middle-sh-result">
<arg value="-c"/>
<arg value="exit 42"/>
</exec>
<!-- Restore logging. -->
<script language="javascript"><![CDATA[
var savedLoggers = project.getReference( "savedLoggers" );
for( var i = 0; i < savedLoggers.length; i++ ) {
var logger = savedLoggers[i];
project.addBuildListener( logger );
}
]]></script>
<echo>Verify logging works again...</echo>
<exec executable="sh" failonerror="false">
<arg value="-c"/>
<arg value="exit 1"/>
</exec>
<echo>By the way, the middle exec returned: ${middle-sh-result}</echo>
</target>
</project>
Output
run:
[echo] Show that exec logs "Result: 1" by default...
[exec] Result: 1
[echo] Disabling logging...
[echo] Verify logging works again...
[exec] Result: 1
[echo] By the way, the middle exec returned: 42

Answer 2

Late answer - but perhaps it will help someone that stumbles across this question searching the internet and does not want to completely disable logging (like Chad Nouis proposed): If one starts the program in a separate shell, the exit code can be controlled.
Ignore/Overwrite with exit code 0:
<exec executable="sh">
<arg value="-c" />
<arg value="cmd-with-non-0-exit.sh || exit 0" />
</exec>
Store exit code <> 0 to property:
<exec executable="sh" outputproperty="cmdOutput">
<arg value="-c" />
<arg value="cmd-with-non-0-exit.sh || echo $?" />
</exec>
The exit code then can be parsed from $cmdOutput.