Maven repositories

README.md

@@ -173,7 +173,7 @@ cellar get-external org.typelevel:cats-core_3:latest cats.Monad
 | `--no-cache` | project commands | Skip classpath cache, re-extract from build tool |
 | `--test` | project commands | Use the test-scope classpath (sbt/scala-cli; not supported for Mill) |
 | `--java-home <path>` | all | Use a specific JDK for JRE classpath |
-| `-r`, `--repository <url>` | external commands | Extra Maven repository URL (repeatable); must be an `http://`, `https://` or `file://` URL |
+| `-r`, `--repository <url>` | external commands | Extra Maven repository URL (repeatable), appended to the configured `maven.repositories`; must be an `http://`, `https://` or `file://` URL |
 | `-l`, `--limit <N>` | `list`, `list-external`, `search`, `search-external` | Max results (default: 50) |
 | `-l`, `--limit <N>` | `get`, `get-external` | Max members to display per section, including companion members (no default) |
 | `--hide-inherited` | `get`, `get-external` | Show only members declared on the type itself |
@@ -234,6 +234,12 @@ Cellar loads configuration from HOCON files and environment variables. Files are
 ### Default config
 
 ```hocon
+maven {
+  # Extra Maven repository URLs for external commands, added to Coursier's
+  # defaults (Maven Central, Ivy local)
+  repositories = []
+}
+
 mill {
   # Binary to invoke when extracting Mill classpaths
   binary = "./mill"           # env: CELLAR_MILL_BINARY
@@ -283,6 +289,22 @@ Use a custom Mill wrapper:
 mill { binary = "./millw" }
 ```
 
+Always resolve external coordinates through an internal repository, so `-r` is no longer needed:
+
+```hocon
+maven {
+  repositories = [
+    "https://artifactory.company.com/maven",
+    "https://artifactory.company.com/maven-snapshots"
+  ]
+}
+```
+
+Maven Central and Ivy local stay available, and CLI `-r` values are appended to the configured list.
+Lists replace rather than merge, so a project-level `maven.repositories` overrides the user-level
+list and `repositories = []` clears it for that project. Configuration holds URLs only —
+credentials come from coursier, as described above.
+
 Or via environment: `CELLAR_SBT_BINARY=sbtn cellar get --module core cats.Monad`
 
 ## Telemetry

cli/src/cellar/cli/CellarApp.scala

@@ -150,11 +150,20 @@ object CellarApp extends ProfilingIOApp:
     Opts.option[Path]("java-home", "Use a specific JDK for JRE classpath").orNone
 
   private val extraReposOpt: Opts[IO[List[Repository]]] =
-    Opts.options[String]("repository", "Extra Maven repository URL (repeatable)", short = "r", metavar = "url")
-      .orEmpty
-      .mapValidated(_.traverse { raw =>
-        RepositoryUrl.parse(raw).leftMap(reason => s"Invalid --repository: $reason").toValidatedNel
-      })
+    Opts.options[String](
+      "repository",
+      "Extra Maven repository URL, appended to configured maven.repositories (repeatable)",
+      short = "r",
+      metavar = "url"
+    ).orEmpty
+      .mapValidated { commandLine =>
+        def validate(source: String)(raw: String) =
+          RepositoryUrl.parse(raw).leftMap(reason => s"Invalid $source: $reason").toValidatedNel
+        (
+          Config.global.maven.repositories.traverse(validate("maven.repositories entry")),
+          commandLine.traverse(validate("--repository"))
+        ).mapN(ExtraRepositories.effective)
+      }
       .map { repos =>
         if repos.isEmpty then IO.pure(Nil)
         else CoursierCredentials.load().map(creds => repos.map(CoursierCredentials.applyTo(_, creds)))

lib/resources/reference.conf

@@ -1,3 +1,10 @@
+maven {
+  # Extra Maven repository URLs used by every external command, in addition to
+  # Coursier's defaults (Maven Central, Ivy local). CLI -r/--repository values
+  # are appended to this list.
+  repositories = []
+}
+
 mill {
   # When running mill, which binary to invoke
   binary = "./mill"

lib/src/cellar/Config.scala

@@ -15,7 +15,11 @@ case class ProfilingConfig(enabled: Boolean, pyroscopeEndpoint: String) derives
 
 case class OtelConfig(enabled: Boolean, endpoint: String) derives ConfigReader
 
+/** Extra Maven repository URLs added to Coursier's defaults for every external command. */
+case class MavenConfig(repositories: List[String]) derives ConfigReader
+
 case class Config(
+    maven: MavenConfig,
     mill: MillConfig,
     sbt: SbtConfig,
     starvationChecks: StarvationChecksConfig,
@@ -28,13 +32,16 @@ object Config {
     sys.props.get("user.home").map(Path(_).resolve(".cellar").resolve("cellar.conf"))
   private[cellar] val defaultProjectPath: Path = Path(".cellar").resolve("cellar.conf")
 
-  private def load(): Config = {
-    val paths = defaultUserPath.toList ++ List(defaultProjectPath)
+  /** Loads with explicit file locations so tests never touch the real user configuration. */
+  private[cellar] def loadFrom(userPath: Option[Path], projectPath: Option[Path]): Config = {
+    val paths = userPath.toList ++ projectPath.toList
     paths
       .foldLeft(ConfigSource.default)((cs, p) => ConfigSource.file(p.toNioPath).optional.withFallback(cs))
       .loadOrThrow[Config]
   }
 
+  private def load(): Config = loadFrom(defaultUserPath, Some(defaultProjectPath))
+
   lazy val global: Config = load()
 
   def loadFresh(): Config = load()

lib/src/cellar/ExtraRepositories.scala

@@ -0,0 +1,12 @@
+package cellar
+
+import coursierapi.{MavenRepository, Repository}
+
+private[cellar] object ExtraRepositories:
+
+  /** Configured repositories first, command-line `-r` values appended.
+    *
+    * Duplicates collapse to their first occurrence, ignoring a trailing slash.
+    */
+  def effective(configured: List[MavenRepository], commandLine: List[MavenRepository]): List[Repository] =
+    (configured ++ commandLine).distinctBy(_.getBase.stripSuffix("/"))

lib/test/src/cellar/ExtraRepositoriesTest.scala

@@ -0,0 +1,67 @@
+package cellar
+
+import cats.effect.IO
+import cats.syntax.all.*
+import coursierapi.MavenRepository
+import fs2.io.file.{Files => Fs2Files, Path}
+import munit.CatsEffectSuite
+import org.typelevel.otel4s.trace.Tracer.Implicits.noop
+
+class ExtraRepositoriesTest extends CatsEffectSuite:
+
+  private def withConfigFiles(userConfig: Option[String], projectConfig: Option[String])(
+      test: Config => IO[Unit]
+  ): IO[Unit] =
+    Fs2Files[IO].tempDirectory.use { dir =>
+      def write(name: String, contents: String): IO[Path] =
+        val file = dir.resolve(name)
+        fs2.Stream.emit(contents).through(Fs2Files[IO].writeUtf8(file)).compile.drain.as(file)
+
+      for
+        userPath    <- userConfig.traverse(write("user.conf", _))
+        projectPath <- projectConfig.traverse(write("project.conf", _))
+        _           <- test(Config.loadFrom(userPath, projectPath))
+      yield ()
+    }
+
+  private def bases(configured: List[String], commandLine: List[String]): List[String] =
+    ExtraRepositories.effective(configured.map(MavenRepository.of), commandLine.map(MavenRepository.of)).map {
+      case maven: MavenRepository => maven.getBase
+      case other                  => fail(s"Expected a MavenRepository, got $other")
+    }
+
+  test("configured repositories come first, command-line values append"):
+    assertEquals(
+      bases(List("https://configured.example/maven"), List("https://cli.example/maven")),
+      List("https://configured.example/maven", "https://cli.example/maven")
+    )
+
+  test("duplicates collapse to their first occurrence, ignoring a trailing slash"):
+    assertEquals(
+      bases(List("https://repo.example/maven"), List("https://repo.example/maven/", "https://other.example/maven")),
+      List("https://repo.example/maven", "https://other.example/maven")
+    )
+
+  test("no configured repositories leaves command-line values untouched"):
+    assertEquals(bases(Nil, List("https://cli.example/maven")), List("https://cli.example/maven"))
+
+  test("default configuration has no extra repositories"):
+    withConfigFiles(None, None)(config => IO(assertEquals(config.maven.repositories, Nil)))
+
+  test("empty project list clears repositories inherited from the user config"):
+    withConfigFiles(
+      userConfig = Some("""maven.repositories = ["https://configured.example/maven"]"""),
+      projectConfig = Some("maven.repositories = []")
+    )(config => IO(assertEquals(config.maven.repositories, Nil)))
+
+  test("configured repository resolves a fixture artifact without a command-line repository"):
+    TestFixtures.assumeFixturesAvailable()
+    withConfigFiles(
+      userConfig = Some(s"""maven.repositories = ["file://${TestFixtures.localM2}"]"""),
+      projectConfig = None
+    ) { config =>
+      val repositories = ExtraRepositories.effective(config.maven.repositories.map(MavenRepository.of), Nil)
+      CoursierFetchClient
+        .fetchClasspath(TestFixtures.scala3Coord, repositories)
+        .map(paths => assert(paths.nonEmpty, "Expected the fixture JAR to resolve through the configured repository"))
+    }

skills/cellar/SKILL.md

@@ -53,7 +53,8 @@ Query any published artifact by explicit coordinate (`group:artifact:version`):
 - For sbt plugins, use the full Scala and sbt suffix: `group:artifact_2.12_1.0:version` (e.g. `org.scala-native:sbt-scala-native_2.12_1.0:latest`)
 - For compiler plugins and other artifacts with full Scala version suffixes, use the full version: `group:artifact_3.3.8:version`
 - Use `latest` as the version to resolve the most recent release
-- `-r`, `--repository <url>`: extra Maven repository (repeatable)
+- `-r`, `--repository <url>`: extra Maven repository (repeatable), appended to the repositories
+  configured under `maven.repositories` in `~/.cellar/cellar.conf` or `.cellar/cellar.conf`
 
 ## Workflow