[Nant-users] value expanded prior to if test

[Castro, Edwin Gabriel (Firing Systems Engr.)]

I am trying pass an <arg> to <exec> depending on the existence of a
<property>. Example:

<exec program="program.exe">
  <arg value="${arg}" if="${property::exists('arg')}" />
</exec>

I receive an error message like the following:

<error>
Property evaluation failed.
Expression: ${arg}
              ^^^
    Property 'arg' has not been set.
</error>

I remember a post a while ago about this problem. Will this be fixed? Or
perhaps I simply misunderstand how this is supposed to work...

I can work around the problem at the moment, but it seems to me like
this would be a simple fix and would increase readability.

I've attached an example buildfile that reproduces this error.

Version: NAnt 0.85 (Build 0.85.1732.0; net-1.0.win32; nightly;
9/28/2004)

arg.build
Description: arg.build