Set property containing the currently executing maven version.

from the thread on the ML, it sounded like it was acceptable usage to grab the RuntimeInformation component (but add an integration test to Maven to make sure it survives any future refactoring).

Just test the property is present, don't bind it to the RuntimeInformation because it will be different in Maven 3.x. The property being available is cool, specifically getting it from the RuntimeInformation component is not. Shouldn't be source dependent.

I looked into it a bit, and I should be able to get the version the same way that it's retrieved when you run "mvn -version" from the command line. It gets the information from the maven core jar, so it wouldn't be dependent on the RuntimeInformation.
I wasn't sure if it should be a system property, or should the scope of the property be more localized?

The RuntimeInformation could be used in a goal in a plugin (maybe the buildnumber plugin?) to allow the version to be accessed in maven pre 3.0.

that's exactly what the runtimeinformation does. I misunderstood what Jason meant on the list by "making it work". If you're happy to settle for making a change to Maven, then putting maven.version into the context for interpolation and anything else that is going to grab it from the session is probably the right way to go. I had the feeling 3.x already has this, but 2.1 doesn't - would need to check though.

Ok, so just to be clear, is it ok to get the version the same way that RuntimeInformation gets it? Specifically getting it from the properties file for maven-core? If not, what is the best way to get the version to make it available?

Sorry, I'm a bit lost about where you are trying to do this. If it's in the core, to set a maven.version property for plugins to use, then the existing code can be used to do that, no need to re-read the properties file.

Or are you looking for what code to put into a plugin today?

I was thinking to make the change directly in maven embedder. Here is a patch to add the version to a system property when maven starts.

yep, that looks exactly right - however, ISTR having that as a system property caused some grief. It would be better to inject it into the properties in the request after it is created - they are still available for interpolation.

Combine that with an IT and I'd say commit away

I'll take a look later this week. There are two branches with lots of changes including the embedder, but this is not hard to add but the embedder is not the right place.

not a regression; pushing to 2.2.x

I remember this being bounced around on list - we need to define the canonical way to get the maven version and make sure it works in 2.2.x and 3.0

And don't use a system property. Change this patch to set a simple property. System properties are bad for || execution and multi-threading in general.

I think this enhancement should really be added, also because of maven3 arriving.
It would help knowing the used maven version used to build in the future.

For instance, I'm currently trying to debug a maven3/maven2 build problem because of a badly built plugin (plugin.xml badly encoded, seems like a bug for maven < 2.2.1). And I've a hard time dichotomizing things to correctly file the corresponding issue.

Cheers

Adding $

sounds like a good idea to me. However, a user should NEVER be able to override it with -D/<properties>. I would make that an outright error.

I'm not sure whether to use just the version number or the full version string for this. For example, "3.0.3" vs "Apache Maven 3.0.3 (r1075438; 2011-02-28 11:31:09-0600)". I'm leaning toward the full version info since this is similar to the version string available in the Ant property "ant.version".

"3.0.3 (r1075438; 2011-02-28 11:31:09-0600)" is another possibility.

I think it would make more sense to a developer to have it in the form of x.y.z (for example 3.1.0). Perhaps there should be two properties. One for the Maven version (in the format I just mentioned) and one that contains the full version info, along with the revision and etc).

Ok, I agree two properties might be best. Anyone currently using the build-helper-maven-plugin to get the version will expect that "maven.version" contains just the simple version, so how about this?

maven.version = "3.0.3"
maven.build.version = "Apache Maven 3.0.3 (r1075438; 2011-02-28 11:31:09-0600)"

Added the new properties in r1147597.
Added integration test in r1147598.

Property documentation should be added as part of MNG-5134.