enforce-once still runs in each child pom

This is a problem in the way maven handles @aggregator. It still executes on each child. The rules need to declare if they are cacheable and the plugin will need to remember the results to speed things up.

Rules now get to decide if they are cacheable and if their results are valid (by checking their parameters against the cached version etc).

http://maven.apache.org/plugins/maven-enforcer-plugin/usage.html still contains this paragraph:

"The enforce goal executes against each project in a multi-project build. The enforce-once goal executes just once per build. This is most effective for the standard rules because the Maven, Java and OS versions will not change between projects in the same build."

Please update it.