[2.x] fix: Include platform suffix in Artifact.artifactName (#9118)

lm-core/src/main/scala/sbt/librarymanagement/ArtifactExtra.scala

@@ -104,7 +104,15 @@ private[librarymanagement] abstract class ArtifactFunctions {
     import artifact.*
     val classifierStr = classifier match { case None => ""; case Some(c) => "-" + c }
     val cross = CrossVersion(module.crossVersion, scalaVersion.full, scalaVersion.binary)
-    val base = CrossVersion.applyCross(artifact.name, cross)
+    val withPlatform = module.crossVersion match {
+      case _: Disabled => artifact.name
+      case _ =>
+        module.platformOpt match {
+          case Some(p) if p.nonEmpty && p != Platform.jvm => s"${artifact.name}_$p"
+          case _                                          => artifact.name
+        }
+    }
+    val base = CrossVersion.applyCross(withPlatform, cross)
     base + "-" + module.revision + classifierStr + "." + artifact.extension
   }
 

lm-core/src/test/scala/sbt/librarymanagement/ArtifactTest.scala

@@ -0,0 +1,41 @@
+package sbt.librarymanagement
+
+import sbt.internal.librarymanagement.UnitSpec
+
+class ArtifactTest extends UnitSpec {
+
+  "Artifact.artifactName" should "include the platform suffix before the Scala suffix" in {
+    val m = ModuleID("com.example", "root-178", "0.1.0-SNAPSHOT")
+      .cross(CrossVersion.binary)
+      .platform("native0.5")
+    val a = Artifact("root-178", "pom", "pom")
+    val sv = ScalaVersion("3.8.3", "3")
+    Artifact.artifactName(sv, m, a) shouldBe "root-178_native0.5_3-0.1.0-SNAPSHOT.pom"
+  }
+
+  it should "omit the platform suffix for jvm" in {
+    val m = ModuleID("com.example", "foo", "1.0.0")
+      .cross(CrossVersion.binary)
+      .platform(Platform.jvm)
+    val a = Artifact("foo", "jar", "jar")
+    Artifact.artifactName(ScalaVersion("3.8.3", "3"), m, a) shouldBe "foo_3-1.0.0.jar"
+  }
+
+  it should "omit platform and cross suffix when crossVersion is disabled" in {
+    val m = ModuleID("com.example", "foo", "1.0.0").platform("native0.5")
+    val a = Artifact("foo", "jar", "jar")
+    Artifact.artifactName(ScalaVersion("3.8.3", "3"), m, a) shouldBe "foo-1.0.0.jar"
+  }
+
+  it should "produce a filename whose base matches the Maven coordinate (#9117)" in {
+    val m = ModuleID("com.indoorvivants", "sniper", "0.0.9-SNAPSHOT")
+      .cross(CrossVersion.binary)
+      .platform("native0.5")
+    val a = Artifact("sniper", "pom", "pom")
+    val sv = ScalaVersion("3.8.3", "3")
+
+    val expectedMavenArtifactId = "sniper_native0.5_3"
+    Artifact.artifactName(sv, m, a) shouldBe
+      s"$expectedMavenArtifactId-0.0.9-SNAPSHOT.pom"
+  }
+}

lm-coursier/src/test/scala/lmcoursier/FromSbtPlatformSpec.scala

@@ -107,4 +107,21 @@ final class FromSbtPlatformSpec extends AnyPropSpec with Matchers {
     // Should just have cross-version suffix, no platform
     module.name.value shouldBe "qux_2.13"
   }
+
+  property("issue #9117: project with native0.5 publishes as _native0.5_3") {
+    val projectID = ModuleID("com.indoorvivants", "sniper", "0.0.9-SNAPSHOT")
+      .withCrossVersion(Binary())
+      .platform("native0.5")
+
+    val (module, version) = FromSbt.moduleVersion(
+      projectID,
+      scalaVersion = "3.8.3",
+      scalaBinaryVersion = "3",
+      optionalCrossVer = false,
+      projectPlatform = Some("native0.5")
+    )
+
+    module.name.value shouldBe "sniper_native0.5_3"
+    version shouldBe "0.0.9-SNAPSHOT"
+  }
 }

main/src/main/scala/sbt/Defaults.scala

@@ -3589,6 +3589,7 @@ object Classpaths {
     val p0 = ModuleID(organization.value, moduleName.value, version.value)
       .cross((projectID / crossVersion).value)
       .artifacts(artifacts.value*)
+      .withPlatformOpt(platform.?.value)
     val p1 = apiURL.value match
       case Some(u) => p0.extra(SbtPomExtraProperties.POM_API_KEY -> u.toURL().toExternalForm)
       case _       => p0

sbt-app/src/sbt-test/dependency-management/platform-artifact-name/build.sbt

@@ -0,0 +1,16 @@
+ThisBuild / organization := "com.example"
+name := "testproj"
+version := "0.1.0-SNAPSHOT"
+scalaVersion := "3.8.3"
+
+platform := "native0.5"
+crossVersion := CrossVersion.binary
+
+lazy val checkPomName = taskKey[Unit]("check POM artifact path includes native0.5_3")
+
+checkPomName := {
+  val converter = fileConverter.value
+  val p = (makePom / artifactPath).value
+  val s = converter.toPath(p).toString
+  assert(s.contains("native0.5_3"), s"expected native0.5_3 in POM path, got: $s")
+}

sbt-app/src/sbt-test/dependency-management/platform-artifact-name/test

@@ -0,0 +1 @@
+> checkPomName