pom.xml environment variable with default fallback

I wasn’t really satisfied with the accepted approach, so I simplified it a little.

Basically set a default property in the normal properties block, and only override when appropriate (instead of an effective switch statement):

<properties>
     <!-- Sane default -->
    <buildNumber>0</buildNumber>
    <!-- the other props you use -->
</properties>

<profiles>
    <profile>
        <id>ci</id>
        <activation>
            <property>
                <name>env.buildNumber</name>
            </property>
        </activation>
        <properties>
            <!-- Override only if necessary -->
            <buildNumber>${env.buildNumber}</buildNumber>
        </properties>
    </profile>
</profiles>