Feature/maven version range

[giulong]

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Problem

As per the usage docs, bumping the Maven version requires manually going on Maven Central to get the latest. It would be nice having the plugin resolve the highest available version automatically.

Proposed solution

Maven already supports Dependency Version Requirement Specification, allowing the definition of a range instead of a fixed one. Though it's not advisable to rely on such a mechanism to manage regular dependencies of an application for the sake of reproducible builds, the wrapper is an external tool for which this issue doesn't apply.

Available Maven versions are taken from maven-metadata.xml.

Rationale

Having a native way to automatically bump the Maven version let us schedule a simple wrapper execution. For instance:

• ./mvnw wrapper:wrapper -Dmaven=3.9.16: fixed versions are considered valid ranges, so no breaking change.
• ./mvnw wrapper:wrapper -Dmaven="[3.0,4.0-alpha)": allows the resolution of the latest 3.x.x version, excluding currently non-stable 4.x.x versions.

Moreover, this is done without relying on external tools such as GitHub actions (as proposed in #331) or bots like Renovate (as proposed in #249).

[giulong]

Bumped to use mockStatic and mockConstruction

[cstamas]

-1

Why not use RepositorySystem, do not replicate the logic.

[giulong]

Added since MetadataXpp3Reader.read() throws XmlPullParserException from this package.

[giulong]

Added to use @ParameterizedTest

[cstamas]

You most probably want this instead #437

[cstamas]

Feel free to incorporate that instead.

[giulong]

You most probably want this instead #437

I was thinking about something like this (currently a draft):

String resolveVersionRange(String version) {
    try {
        Artifact artifact = new DefaultArtifact("org.apache.maven:apache-maven:" + version);
        VersionRangeRequest versionRangeRequest = new VersionRangeRequest();
        versionRangeRequest.setArtifact(artifact);
        versionRangeRequest.setRepositories(session.getCurrentProject().getRemotePluginRepositories());

        return repositorySystem
                .resolveVersionRange(repositorySystemSession, versionRangeRequest)
                .getHighestVersion()
                .toString();
    } catch (VersionRangeResolutionException e) {
        return version;
    }
}

Maybe I'm missing something, I'll check your suggestion in the next days

[cstamas]

Yes, that looks good as well, but several remarks:

• getHighestVersion may return SNAPSHOT, hence the loop in my code
• version may be just version, so all this is not needed (the logic in my code), but you are right, this mojo is invoked by user, no need to complicate or to be "fast". Simple is better.

Otherwise, yes, this is the right way, no need to fiddle with XML parsing etc.

[giulong]

getHighestVersion may return SNAPSHOT, hence the loop in my code

VersionRangeRequest has a constructor accepting the nature (snapshot/release/both). Leveraging that one, the method would be:

String resolveMavenVersion(String version) {
    try {
        Artifact artifact = new DefaultArtifact("org.apache.maven:apache-maven:" + version);
        VersionRangeRequest request = new VersionRangeRequest(
                artifact, session.getCurrentProject().getRemotePluginRepositories(), RELEASE, "wrapper"); // <-- here
        
        return repositorySystem
                .resolveVersionRange(repositorySystemSession, request)
                .getHighestVersion()
                .toString();
    } catch (VersionRangeResolutionException e) {
        return version;
    }
}

What do you think? Is there anything else to address?

Edit:
that constructor, along with the setter to specify the nature, come with version 2.0.11, while maven-core is bringing version 1.9.27 as transitive dependencies:

[INFO] --- dependency:3.11.0:tree (default-cli) @ maven-wrapper-plugin ---
[INFO] org.apache.maven.plugins:maven-wrapper-plugin:maven-plugin:3.3.5-SNAPSHOT
[...]
[INFO] |  +- org.apache.maven.resolver:maven-resolver-impl:jar:1.9.27:provided
[INFO] |  |  \- org.apache.maven.resolver:maven-resolver-named-locks:jar:1.9.27:provided
[INFO] |  +- org.apache.maven.res`olver:maven-resolver-spi:jar:1.9.27:provided
[INFO] |  +- org.apache.maven.resolver:maven-resolver-util:jar:1.9.27:provided