Archetype fails on maven version detection on some Linux distributions

[tomas-langer]

Environment Details

• Helidon Version: 2.0.0
• JDK version: OpenJDK 14
• OS: Linux
• Maven 3.6.3

---

The maven core library is called maven-core-3.x.jar. Our detection mechanism in Groovy script expects it to have full version.
The detection mechanism fails and reports the version is not good enough:

Failed to execute goal org.apache.maven.plugins:maven-archetype-plugin:3.1.2:generate (default-cli) on project standalone-pom: Requires Maven >= 3.2.5 -> [Help 1]

We should change our version detection mechanism to work for such scenarios (or accept "unknown" maven versions instead of failing).

[gargoyle]

I'm not sure where the groovy script lives and I'm a bit of a groovy novice, but perhaps something like this could be used to reach inside the .jar and pull the value directly from the manifest instead of relying on the filename?

(Note, Crude adaption of the code you pasted in Slack)

def mavenCoreJar = mavenLibDir.list().find { it.startsWith("maven-core-") }
        if (mavenCoreJar == null) {
            throw new IllegalStateException("Unable to determine Maven version")
        }
        String mavenVersion = new java.util.jar.JarFile(mavenCoreJar).manifest.mainAttributes.getValue("Implementation-Version");
        ComparableVersion minMavenVersion = new ComparableVersion("3.2.5")
        if (new ComparableVersion(mavenVersion) < minMavenVersion) {
            throw new IllegalStateException("Requires Maven >= 3.2.5")
        }

[barchetta]

This looks like an issue when maven is install via a Linux package (as opposed to direct maven download). For example: https://packages.ubuntu.com/eoan/all/libmaven3-core-java/filelist

A work-around is to install maven directly from Apache: https://maven.apache.org/download.cgi

Poking around Linux distributions I've seen maven-core.jar, maven-core-3.x.jar, maven-core-<fullversion>.jar