How to exclude intra-project dependency when running maven dependency:go-offline

Question

I have a multi-module project where I want to download all dependencies for offline use. I do this using the mvn dependency:go-offline goal. In the project, there is one module X that depends on another module Y. Since the dependency:go-offline command does not build the modules, there is an error when building X that the dependency Y is not found:

$ mvn dependency:go-offline -Dmaven.artifact.threads=30

 Failure to find se.cust.id:Y:jar:1.2.3-SNAPSHOT in https://mvn.com.com/repository/com-snapshots/ was cached in the local repository, resolution will not be reattempted until the update interval of com-snapshots has elapsed or updates are forced

I've tried to make Maven ignore this dependency by running

$ mvn dependency:go-offline -DexcludeArtifactIds=Y

But this results in the same error. What is the proper way of excluding dependencies here?

Answer 1

Adding maven-dependency-plugin to the parent pom.xml worked for me

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-dependency-plugin</artifactId>
  <version>3.1.2</version>
</plugin>

Answer 2

I ran across the problem while encapsulating a maven build with a Dockerfile (like so: http://whitfin.io/speeding-up-maven-docker-builds/)

My workaround so far is to just let the dependency-fetch fail, which looks like this in my Dockerfile:

RUN mvn -B dependency:go-offline -DexcludeGroupIds=my.company || true

I can tell that the -DexcludeGroupIds doesn't work because I get an error:

Failure to find my.company:subproject-built-here:jar:1-SNAPSHOT in http://packages.confluent.io/maven/ was cached in the local repository, resolution will not be reattempted until...

Enough of the dependencies are downloaded and cached that I still see a speedup later on, but I'd prefer to prevent the error rather than ignoring it.