Use Order[Version] to simplify MillAlg.content (scala-steward-org#3540)

With our `Version` data type and its `Order` instance we can simplify
`MillAlg.content` because we can just check if a Mill version is >= 0.7
and < 0.9 for example without extracting the minor version number.

Author: fthomas

modules/core/src/main/scala/org/scalasteward/core/buildtool/mill/MillAlg.scala

@@ -110,25 +110,19 @@ final class MillAlg[F[_]](defaultResolver: Resolver)(implicit
 }
 
 object MillAlg {
-  private[mill] def millMinVersion(millVersion: Option[Version]): Option[String] =
-    millVersion.flatMap(_.value.trim.split("[.]", 3).take(2).lastOption)
-
   private[mill] val cliPluginCoordinate: String =
     s"ivy:${org.scalasteward.core.BuildInfo.organization}::${org.scalasteward.core.BuildInfo.millPluginArtifactName}::${org.scalasteward.core.BuildInfo.millPluginVersion}"
 
-  private[mill] def content(millVersion: Option[Version]) = {
-    def rawContent(millBinPlatform: String) =
-      s"""|import $$ivy.`${org.scalasteward.core.BuildInfo.organization}::${org.scalasteward.core.BuildInfo.millPluginArtifactName}_mill${millBinPlatform}:${org.scalasteward.core.BuildInfo.millPluginVersion}`
-          |""".stripMargin
-
-    millMinVersion(millVersion) match {
-      case None => rawContent("$MILL_BIN_PLATFORM")
-      // We support these platforms, but we can't take the $MILL_BIN_PLATFORM support for granted
-      case Some("6")             => rawContent("0.6")
-      case Some("7") | Some("8") => rawContent("0.7")
-      case Some("9")             => rawContent("0.9")
-      case _                     => rawContent("$MILL_BIN_PLATFORM")
+  private[mill] def content(millVersion: Option[Version]): String = {
+    // We support these platforms, but we can't take the $MILL_BIN_PLATFORM support for granted
+    val millBinPlatform = millVersion match {
+      case Some(v) if v >= Version("0.10") => "$MILL_BIN_PLATFORM"
+      case Some(v) if v >= Version("0.9")  => "0.9"
+      case Some(v) if v >= Version("0.7")  => "0.7"
+      case Some(v) if v >= Version("0.6")  => "0.6"
+      case _                               => "$MILL_BIN_PLATFORM"
     }
+    s"""import $$ivy.`${org.scalasteward.core.BuildInfo.organization}::${org.scalasteward.core.BuildInfo.millPluginArtifactName}_mill${millBinPlatform}:${org.scalasteward.core.BuildInfo.millPluginVersion}`"""
   }
 
   val extractDeps: String = "org.scalasteward.mill.plugin.StewardPlugin/extractDeps"

modules/core/src/test/scala/org/scalasteward/core/buildtool/mill/MillAlgTest.scala

@@ -100,14 +100,4 @@ class MillAlgTest extends FunSuite {
     assert(MillAlg.content(Some(Version("0.9.14"))).contains("_mill0.9"))
     assert(MillAlg.content(Some(Version("0.10.0"))).contains("_mill$MILL_BIN_PLATFORM"))
   }
-
-  test("mill version") {
-    assert(MillAlg.millMinVersion(None).isEmpty)
-    assert(MillAlg.millMinVersion(Some(Version("0.6.1"))).contains("6"))
-    assert(MillAlg.millMinVersion(Some(Version("0.7.0"))).contains("7"))
-    assert(MillAlg.millMinVersion(Some(Version("0.8.0"))).contains("8"))
-    assert(MillAlg.millMinVersion(Some(Version("0.9.14"))).contains("9"))
-    assert(MillAlg.millMinVersion(Some(Version("0.10.0"))).contains("10"))
-    assert(MillAlg.millMinVersion(Some(Version("0.11.0"))).contains("11"))
-  }
 }