Phase 01: Maven Central metadata client

Status: Planned

Deliverables

1. package3/kotlin/maven/client.go — HTTP client for Maven Central metadata.
   • FetchPOM(coord Coordinate) (*POM, error) — fetch and parse the POM XML.
   • FetchModuleMetadata(coord Coordinate) (*GradleModule, error) — fetch and parse the .module file (Gradle Module Metadata).
   • ResolveVersionRange(groupID, artifactID, versionRange string) (string, error) — resolve a version range to a concrete version using the Maven metadata XML (maven-metadata.xml).
   • FetchMavenMetadata(groupID, artifactID string) (*MavenMetadata, error) — fetch maven-metadata.xml listing all available versions.
2. package3/kotlin/maven/pom.go — POM XML struct and parser (using encoding/xml).
3. package3/kotlin/maven/graph.go — ResolveTransitive(rootCoords []Coordinate) ([]Coordinate, error) — BFS transitive dependency resolution, handling <exclusions>, <scope>, and dependency management sections.
4. package3/kotlin/maven/gmm.go — Gradle Module Metadata parser and JVM variant selector.
5. package3/kotlin/maven/registry.go — registry configuration: Maven Central base URL, JitPack, Google Maven, and custom URL support.

Maven Central metadata protocol

Maven Central serves metadata at:

• https://repo1.maven.org/maven2/{group/path}/{artifact}/{version}/{artifact}-{version}.pom
• https://repo1.maven.org/maven2/{group/path}/{artifact}/maven-metadata.xml
• https://repo1.maven.org/maven2/{group/path}/{artifact}/{version}/{artifact}-{version}.module

Version range resolution reads maven-metadata.xml which lists all available versions and the <release> and <latest> tags.

Gate

Resolve [email protected] and its 11 transitive dependencies from Maven Central. Validate:

1. Correct transitive graph (11 specific artifacts).
2. All POMs parsed without error.
3. No excluded dependencies included.
4. scope = "test" and scope = "provided" dependencies excluded from the compile graph.
5. JVM variant correctly selected from the kotlinx-coroutines-core-1.7.3.module GMM file.