How to execute tasks conditionally using the maven-antrun-plugin?

I need to execute some ant commands depending on an environment variable passed in as a parameter to the maven build command.

At the moment I have 3 tasks blocks and only the tasks block with no condition is being executed.

<tasks name="isProdCheck">
  <condition property="isProd">
    <equals arg1="${environment}" arg2="PROD" />
  </condition>
</tasks>

<tasks if="isProd" depends="isProdCheck">
...
</tasks>

<tasks>
... I am the only block executed
</tasks>

What am I doing wrong, is there a better way to do this?

First, according to Maven 1.x website, the current stable release for maven 1.x is version 1.1, not 1.4. Second, there is no AntRun Plugin version 1.7 and, to my knowledge, this is a Maven 2 plugin. Third, the syntax you are using seems very similar to Using Attributes which, again, is about Maven 2.

So, I may be missing something but, this is very confusing and you should maybe clarify these points in your question.

Anyway, as you explicitly mentioned Maven 1, I'll try to answer. If I remember well, I would write a custom goal and use Jelly's core:if or core:when. To do so, provide something like this in maven.xml:

<project xmlns:j="jelly:core" xmlns:ant="jelly:ant">
  <goal name="my-goal">
    <j:if test="${environment == 'PROD'}">
      <ant:xxx .../>
    </j:if>
  </goal>
</project>

To be honest, I really hope you have a good reason to prefer Maven 1.x over Maven 2.x :)

UPDATE: It appears that the OP is actually using Maven 2 so I'll update my question accordingly. To implement the desired behavior, you could use Ant-contrib's if task as shown below:

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-antrun-plugin</artifactId>
        <version>1.3</version>
        <executions>
          <execution>
            <phase>compile</phase>
            <goals>
              <goal>run</goal>
            </goals>
            <configuration>
              <tasks>
                <taskdef resource="net/sf/antcontrib/antcontrib.properties"
                  classpathref="maven.plugin.classpath" />
                <if>
                  <equals arg1="${foo}" arg2="bar" />
                  <then>
                    <echo message="The value of property foo is bar" />
                  </then>
                  <else>
                    <echo message="The value of property foo is not bar" />
                  </else>
                </if>
              </tasks>
            </configuration>
          </execution>
        </executions>
        <dependencies>
          <dependency>
            <groupId>ant-contrib</groupId>
            <artifactId>ant-contrib</artifactId>
            <version>20020829</version>
          </dependency>
        </dependencies>
      </plugin>
    </plugins>
  </build>

And then call mvn compile -Dfoo=bar (this is just an example).

But, all this is not the "maven way" to do things. Now that I understand a bit better what you are trying to do (but not entirely as you didn't explain your ultimate goal), I think that using build profiles would be more appropriate and, having read your own answer, I think that you are over complicating things (and that you are on the wrong path).

I understand that you are a Maven beginner but I'd suggest to try to use it though instead of falling back on Ant or you won't get the benefits of it. Also, when opening a question, instead of asking for a specific solution, you should rather explain your general problem, you'll get better answers. Here, I can't provide more guidance as I don't know what you are really trying to achieve.