Groovy Maven Compilation fails with error: Unable to determine Groovy version. Is Groovy declared as a dependency? - maven

Question

I have a fairly vanilla groovy project that builds using maven. It utilises the gmavenplus plugin, with the pom lifted straight from the gmaven plus web page
pom looks something like this:
<project>
<build>
<plugins>
<plugin>
<groupId>org.codehaus.gmavenplus</groupId>
<artifactId>gmavenplus-plugin</artifactId>
<version>1.8.0</version>
<executions>
<execution>
<goals>
<goal>addSources</goal>
<goal>addTestSources</goal>
<goal>compile</goal>
<goal>compileTests</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.codehaus.groovy</groupId>
<artifactId>groovy-all</artifactId>
<!-- any version of Groovy \>= 1.5.0 should work here -->
<version>2.5.8</version>
<type>pom</type>
</dependency>
</dependencies>
</project>
When I build, I get the following error on the compile stage.
[INFO] --- gmavenplus-plugin:1.8:compile (default) # myapp---
[INFO] Unable to get Groovy version from GroovySystem, trying InvokerHelper.
[WARNING] Unable to get Groovy version from InvokerHelper or GroovySystem, trying jar name.
[ERROR] Unable to determine Groovy version. Is Groovy declared as a dependency?
And the final maven error results in this:
[ERROR] Failed to execute goal org.codehaus.gmavenplus:gmavenplus-plugin:1.8:compile (default) on project myapp: Execution default of goal org.codehaus.gmavenplus:gmavenplus-plugin:1.8:compile failed. NullPointerException -> [Help 1]
I have tried all manner of tricks, hacks and cajoling to get it to compile. I actually got it working in Intellij by adding the groovy runtime as a direct module dependency (rather than a maven managed dependency), but this doesn't work from the command line.
I had previously had a similar setup working on gmaven plus 1.6 and groovy 2.4.7 on the same laptop, no idea why this is broken now.

Answer 1

So I eventually got it working properly by deleting the entire codehaus dir in the .m2 repo. Re-downloading everything seemed to sort it out and now it all works correctly without any hacks.
This github issue is somewhat related - https://github.com/groovy/GMavenPlus/issues/84 - and the final comment led me to zapping the repo.