Using MAVEN_HOME may clash with other tools

[OPeyrusse]

As part of the installation process [1], the last command is to run mvnd --install.
This is returning the following error:

Exception in thread "main" java.lang.IllegalStateException: Cannot install if mvnd.home /opt/sdkman/candidates/maven/current exists. Delete it if you want to reinstall.
at org.jboss.fuse.mvnd.client.Installer.installServer(Installer.java:55)
at org.jboss.fuse.mvnd.client.DefaultClient.install(DefaultClient.java:98)
at org.jboss.fuse.mvnd.client.DefaultClient.execute(DefaultClient.java:152)
at org.jboss.fuse.mvnd.client.DefaultClient.main(DefaultClient.java:68)

The reported directory is my current installation. It seems that this happens because the variable MAVEN_HOME is set in my environment.

I see that mvnd --install created a bin directory under .m2/mvnd/<version>. But I don't understand why the failure, particularly as MAVEN_HOME is a variable for maven1, and mvnd claims to be a maven 3+.

Can you explain the reason for such a design? As I plan to call mvnd explicitly instead of mvn, I don't want to enforce a path to the provided maven script.

[1] https://github.com/mvndaemon/mvnd#install-mvnd

[ppalaga]

Thanks for the report, I think this is a valid issue. We better should not mess with MAVEN_HOME that can be set/used by other tools with incompatible design. I think we should switch to MVND_HOME and mvnd.home. WDYT, @gnodet ?

[ppalaga]

Also note that we are about to make mvnd installable by sdkman in #48. Solving that probably requires to solve this too.

[OPeyrusse]

That's really cool. I have checked that issue 5 days ago but did not found an easy tutorial on how to do it so I let it pass by.
I can help in any way, do tell me.

[OPeyrusse]

Many thanks. Waiting for the next release, apparently in sdkman 🚀