This is because the maven.jar dependency is now overriden in all plugins (in plugins-parent) which was not the case before (only defined in some plugins)

Ouh ouh ; Classpath.jelly requests the cactus dependency of the maven plugin so it's really nasty to test on that (if you have another cactus plugin, it might break).

Lukas, can you help?

I've "fixed" the cactus dependency problem but we need to investigate. The current cactus dependency is 13-1.6.1 but the cactus plugin expected 13-1.7. I tried to retrieve the version from the plugin to automate this but it does not work so I changed it this way

<echo>Warning, expecting cactus version 13.1-7 from current cactus plugin</echo>
<x:set var="countCactus" select="count($classpathDoc/classpath/classpathentry[contains(@path,'MAVEN_REPO/cactus/jars/cactus-13-1.7.jar')])"/>

Further on, the plugin breaks and I think we have a bug

<classpathentry excluding="" including="" kind="src" path="src/test">
  </classpathentry>
  <classpathentry output="target/test-classes" kind="src" path="src/test">
  </classpathentry>

To me, this entry is duplicated right?

The error is here

<!-- don't add duplicate directories -->
          <j:if
            test="${resourceDirectoryFile.exists() and !resourceDirectory.equals(srcDir) and (!resourceDirectory.equals(testSrcDir) or !unitTestSourcesPresent)}">
            <classpathentry kind="src" path="${resourceDirectory}" including="${includingAsString}"
              excluding="${excludingAsString}" />
          </j:if>

mmm weird. I think the jelly test is not working as expected:

    [echo] resourceDirectoryFile.exists(): true
    [echo] resourceDirectory.equals(srcdir): false
    [echo] resourceDirectory.equals(testSrcDir): false
    [echo] unitTestSourcesPresent: true
    [echo] Will add entry for src/test
    [echo] Contains JUnit tests
    [echo] Setting compile of src/test to target/test-classes

should be a 'and' I guess for the last test

Ok found it, cactus was reseting the testSrcDir to a wrong value.

This is fixed, execpt the cactus dependency thingy.

It's not fixed for me, plugin:test still fails for the same reason that I stated above. (I never noticed the cactus problem as I never used cactus and don't have it installed.) I can fix it easily but I don't know what is actually the expected entry in .classpath, is it

<classpathentry kind="lib" path="MAVEN_REPO/maven/jars/maven.jar"></classpathentry>

or is it

<classpathentry kind="lib" path="${MAVEN_HOME}/lib/maven.jar"></classpathentry>
?

Well. I did not have to change anything for me, it worked in a first place.

Expected entry is 'MAVEN_REPO/maven/jars/maven.jar'

Fixed. We now check for both classpathentries, at least one of them has to be present.