mvnd fails if there is no .mvn/ dir in the user home

[tadayosi]

Right after mvnd --install, mvnd fails with the following error:

$ mvnd --version
Maven Daemon 0.0.0 (native)
Exception in thread "main" java.lang.IllegalStateException: Could not detect maven.multiModuleProjectDirectory by climbing up from [/home/tasato] seeking a .mvn directory. You may want to create a .mvn directory in the root directory of your source tree.
	at org.jboss.fuse.mvnd.client.Environment.lambda$findMultiModuleProjectDirectory$4(Environment.java:127)
	at org.jboss.fuse.mvnd.client.Environment$EnvValue.get(Environment.java:246)
	at org.jboss.fuse.mvnd.client.Environment$EnvValue.asPath(Environment.java:258)
	at org.jboss.fuse.mvnd.client.Environment.findMultiModuleProjectDirectory(Environment.java:131)
	at org.jboss.fuse.mvnd.client.ClientLayout.getEnvInstance(ClientLayout.java:45)
	at org.jboss.fuse.mvnd.client.DefaultClient.lambda$main$0(DefaultClient.java:69)
	at org.jboss.fuse.mvnd.client.DefaultClient.execute(DefaultClient.java:170)
	at org.jboss.fuse.mvnd.client.DefaultClient.main(DefaultClient.java:69)

Manually creating a directory .mvn/ in the user home solves the error, but it's handy if mvnd auto resolves it.

[ppalaga]

Yeah, I admit it's not especially robust, but we basically mimic, what stock Maven does in mvn.[sh|cmd]. The only substantial difference is that while Maven can do without maven.multiModuleProjectDirectory we cannot (or maybe we could?).

it's handy if mvnd auto resolves it.

I wonder how? I do not think we can reliably autodetect the top level directory of any random multimodule project.

[tadayosi]

I thought that mvnd could just mkdir $HOME/.mvn if it doesn't exist. Not sure if it's a silly hack or not though.

[gnodet]

@tadayosi there's a misunderstanding here. mvnd is looking for [project]/.mvn dir to detect the root directory of a multiproject module, not $HOME/.mvn.

[ppalaga]

No, .mvn directory is supposed to mark the root of a multimodule maven project and we cannot know where it is. The bottom line is that mvnd --version shouldn't really require a maven project at all.

[tadayosi]

Thanks for the explanation. So there are a couple of suggestions here:

1. Make mvnd --version (and possibly other non-project general options) not rely on .mvn/
2. For project-related commands, show more use-friendly message in the absence of .mvn/ tracing up the dir hierarchy