Having <scope>provided</scope> is fairly common, as you know. Many Java webapps, for example, include the servlet-api, jsp-api, and related jars with provided scope on their classpath. So here's my vote for fixing it soon

Maven version: 2.0.8, Java version: 1.5.0_14

A new 2.2-SNAPSHOT has been deployed to the snapshot-repository. Please give that version a try to verify that this issue has been properly resolved.

Using the demo project and the unpatched plugin, the following behavior occurred (with Maven 2.0.8):
Running mvn clean checkstyle:checkstyle failed to locate the compile-time dependency on log4j whereas mvn clean compile runs checkstyle as part of the default lifecycle and succeeds.

I have committed a fix for this in r617973.

I was a few minutes too late... anyway, take it as as "worked for me" feedback then.

By the way, I wonder whether @requiresDependencyResolution is really required for the CheckstyleViolationCheckMojo. It does not invoke Checkstyle directly but forks the CheckstyleReport mojo which in turn gets the dependencies via its on annotation.

I wasn't sure myself whether the annotation was required in CheckstyleViolationCheckMojo, but I figured it can't harm to have it there.

This issue has been verified and closed. If you think it should be reopened you need to provide us with a sample project that can be used to reproduce the problems.