[Java.Interop.Tools.Maven] Validate Artifact coordinates

[jonathanpeppers]

Context: dotnet/android's <AndroidMavenLibrary> MSBuild item relies on Artifact/Artifact.TryParse to validate Maven coordinates supplied by users, but today the constructor blindly assigns its fields and TryParse only checks for three colon-separated parts. Empty strings, whitespace, path traversal sequences (../), and characters that are illegal per the Maven coordinate spec all slip through.

This PR adds structural validation to Artifact:

• groupId and artifactId must match [A-Za-z0-9_\-.]+ per the Maven Coordinates spec.
• version rejects whitespace, :, and path separators (/, \). Maven versions are otherwise permissive, so no further parsing is attempted.
• The constructor throws ArgumentNullException / ArgumentException with the offending parameter and value.
• TryParse returns false for any invalid input (and requires all three parts to be non-empty) without throwing.
• Parse continues to throw ArgumentException with the existing message format.

The constructor still allows an empty version so that existing internal callers — Dependency.ToArtifact() and Project.TryGetParentPomArtifact() — can keep producing partial coordinates when a POM omits <version> and inherits it from a parent POM. The user-input paths (TryParse/Parse) still require a non-empty version.

Tests

Added tests/Java.Interop.Tools.Maven-Tests/ArtifactTests.cs covering:

• Valid coordinates round-trip through ctor / TryParse / Parse, including GroupId / Id / Version / ArtifactString / VersionedArtifactString.
• Invalid inputs rejected by both ctor (throws) and TryParse (returns false, out param null): null, empty, whitespace-only, wrong number of :-separated parts, illegal chars (space, :, /, @, !, etc.), and path-traversal sequences like ../ / ..\ in any of the three positions including the version.
• The constructor's empty-version allowance is covered by a dedicated test.

All 92 tests in Java.Interop.Tools.Maven-Tests pass.

Benefit to downstream

<AndroidMavenLibrary> (whose MavenExtensions.TryParseArtifactWithVersion currently only splits on :) gets stricter validation for free as soon as it picks up this version of Java.Interop.Tools.Maven.

[Copilot]

Pull request overview

This PR strengthens Java.Interop.Tools.Maven.Models.Artifact so it properly validates Maven coordinates (groupId/artifactId/version) when constructed or parsed, preventing malformed or potentially unsafe user-supplied coordinates from slipping through (notably for downstream consumers like dotnet/android’s <AndroidMavenLibrary>).

Changes:

• Added validation to Artifact constructor for groupId/artifactId character set and for version (rejecting whitespace, :, and path separators), while still allowing an empty constructor version for internal “inherited version” scenarios.
• Updated Artifact.TryParse to reject invalid inputs (including null and empty parts) without throwing.
• Added NUnit tests covering valid/invalid coordinates and the constructor’s empty-version allowance.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
tests/Java.Interop.Tools.Maven-Tests/ArtifactTests.cs	Adds comprehensive tests for Artifact ctor/TryParse/Parse validation behavior.
src/Java.Interop.Tools.Maven/Models/Artifact.cs	Implements stricter structural validation for Maven coordinates and updates parsing behavior.