SeparateEachFile

input/src/main/scala/fix/SeparateEachFileWarnTest.scala

@@ -0,0 +1,7 @@
+/*
+rule = SeparateEachFileWarn
+ */
+package fix
+
+trait SeparateEachFileWarnTest // assert: SeparateEachFileWarn
+class SeparateEachFileWarnTest1

input/src/main/scala/fix/SeparateEachFileWarnTest2.scala

@@ -0,0 +1,10 @@
+/*
+rule = SeparateEachFileWarn
+SeparateEachFileWarn.limit = 5
+ */
+package fix
+
+trait SeparateEachFileWarnTest2_1
+trait SeparateEachFileWarnTest2_2
+trait SeparateEachFileWarnTest2_3
+trait SeparateEachFileWarnTest2_4

output/src/main/scala/fix/SeparateEachFileWarnTest.scala

@@ -0,0 +1,4 @@
+package fix
+
+trait SeparateEachFileWarnTest 
+class SeparateEachFileWarnTest1

output/src/main/scala/fix/SeparateEachFileWarnTest2.scala

@@ -0,0 +1,6 @@
+package fix
+
+trait SeparateEachFileWarnTest2_1
+trait SeparateEachFileWarnTest2_2
+trait SeparateEachFileWarnTest2_3
+trait SeparateEachFileWarnTest2_4

rules/src/main/scala/fix/SeparateEachFileConfig.scala

@@ -0,0 +1,36 @@
+package fix
+
+import scalafix.lint.LintSeverity
+import java.util.Locale
+import metaconfig.ConfDecoder
+import metaconfig.generic.Surface
+
+case class SeparateEachFileConfig(
+  limit: Int,
+  severity: LintSeverity
+)
+
+object SeparateEachFileConfig {
+
+  val default: SeparateEachFileConfig = SeparateEachFileConfig(
+    limit = 2,
+    severity = LintSeverity.Warning,
+  )
+
+  implicit val surface: Surface[SeparateEachFileConfig] =
+    metaconfig.generic.deriveSurface[SeparateEachFileConfig]
+
+  private implicit val lintSeverityDecoderInstance: ConfDecoder[LintSeverity] = { conf =>
+    conf.as[String].map(_.toUpperCase(Locale.ROOT)).map {
+      case "ERROR" =>
+        LintSeverity.Error
+      case "INFO" =>
+        LintSeverity.Info
+      case _ =>
+        LintSeverity.Warning
+    }
+  }
+
+  implicit val decoder: ConfDecoder[SeparateEachFileConfig] =
+    metaconfig.generic.deriveDecoder(default)
+}

rules/src/main/scala/fix/SeparateEachFileRewrite.scala

@@ -0,0 +1,84 @@
+package fix
+
+import metaconfig.Configured
+import scala.meta._
+import scalafix.v1._
+import java.io.File
+import java.nio.charset.StandardCharsets
+import java.nio.file.Files
+import scala.meta.inputs.Input
+
+class SeparateEachFileRewrite(config: SeparateEachFileConfig) extends SyntacticRule("SeparateEachFileRewrite") {
+
+  def this() = this(SeparateEachFileConfig.default)
+
+  override def withConfiguration(config: Configuration): Configured[Rule] =
+    config.conf
+      .getOrElse("SeparateEachFileRewrite")(this.config)
+      .map(newConfig => new SeparateEachFileRewrite(newConfig))
+
+  private def maxOption[A: Ordering](xs: Seq[A]): Option[A] =
+    if (xs.isEmpty) None else Option(xs.max)
+
+  override def fix(implicit doc: SyntacticDocument): Patch = {
+    PartialFunction
+      .condOpt(doc.input) {
+        case f: Input.File =>
+          f.path.toFile
+        case f: Input.VirtualFile =>
+          new File(f.path)
+      }
+      .foreach { input =>
+        val topLevelValues = doc.tree.collect {
+          case t: (Stat.WithTemplate & Member & Stat.WithMods)
+              if isTopLevel(t) && t.templ.inits.isEmpty && !t.is[Defn.Object] =>
+            t
+        }
+
+        if (
+          (topLevelValues.lengthCompare(config.limit) >= 0) && topLevelValues.forall(_.mods.forall(!_.is[Mod.Sealed]))
+        ) {
+          val headerLastPos = {
+            maxOption(
+              doc.tree.collect {
+                case i: Import if isTopLevel(i) => i.pos.end
+              }
+            ).orElse(
+              maxOption(
+                doc.tree.collect { case p: Pkg =>
+                  p.ref.pos.end
+                }
+              )
+            ).getOrElse(0)
+          }
+          val header = doc.input.text.take(headerLastPos)
+
+          assert(input.delete())
+
+          val xs = doc.tree.collect {
+            case t: (Stat.WithTemplate & Member) if isTopLevel(t) =>
+              t
+          }.groupBy(_.name.value)
+
+          xs.foreach { case (k, v) =>
+            Files.write(
+              new File(
+                input.getParentFile,
+                s"${k}.scala"
+              ).toPath,
+              (header + "\n\n" + v
+                .sortBy(_.getClass.getName)
+                .map { x =>
+                  (doc.comments.leading(x).toSeq.sortBy(_.pos.start).map(_.toString) :+ x.toString).mkString("\n")
+                }
+                .mkString("\n", "\n\n", "\n")).getBytes(StandardCharsets.UTF_8)
+            )
+          }
+        }
+      }
+
+    Patch.empty
+  }
+
+  private def isTopLevel(t: Tree): Boolean = t.parent.forall(_.is[Pkg])
+}

rules/src/main/scala/fix/SeparateEachFileWarn.scala

@@ -0,0 +1,38 @@
+package fix
+
+import metaconfig.Configured
+import scala.meta._
+import scalafix.v1._
+
+class SeparateEachFileWarn(config: SeparateEachFileConfig) extends SyntacticRule("SeparateEachFileWarn") {
+
+  def this() = this(SeparateEachFileConfig.default)
+
+  override def withConfiguration(config: Configuration): Configured[Rule] =
+    config.conf.getOrElse("SeparateEachFileWarn")(this.config).map(newConfig => new SeparateEachFileWarn(newConfig))
+
+  override def fix(implicit doc: SyntacticDocument): Patch = {
+    val topLevelValues = doc.tree.collect {
+      case t: (Stat.WithTemplate & Stat.WithMods & Member)
+          if t.parent.forall(_.is[Pkg]) && t.templ.inits.isEmpty && !t.is[Defn.Object] =>
+        t
+    }
+
+    if ((topLevelValues.lengthCompare(config.limit) >= 0) && topLevelValues.forall(_.mods.forall(!_.is[Mod.Sealed]))) {
+      Patch.lint(
+        Diagnostic(
+          id = "",
+          message = Seq(
+            s"too many top level classes. please separate file. ${topLevelValues.size} ",
+            topLevelValues.map(_.name.value).mkString("[", ", ", "]")
+          ).mkString(""),
+          position = topLevelValues.head.pos,
+          severity = config.severity
+        )
+      )
+    } else {
+      Patch.empty
+    }
+  }
+
+}

sbt-test/SeparateEachFileRewrite/test-1/build.sbt

@@ -0,0 +1,14 @@
+ThisBuild / scalafixDependencies += "com.github.xuwei-k" %% "scalafix-rules" % sys.props("scalafix-rules.version")
+
+TaskKey[Unit]("check") := {
+  val names = Set("X1.scala", "X2.scala", "A.scala")
+  val actualNames = file("src/main/scala/foo").listFiles().map(_.getName).toSet
+  assert(actualNames == names, actualNames)
+  names.foreach {
+    f =>
+      val actual = IO.read(file(s"src/main/scala/foo/${f}"))
+      val expect = IO.read(file(s"expect/${f}"))
+      sys.process.Process(Seq("diff", s"src/main/scala/foo/${f}", s"expect/${f}")).!
+      assert(actual == expect, actual)
+  }
+}

sbt-test/SeparateEachFileRewrite/test-1/expect/A.scala

@@ -0,0 +1,6 @@
+package foo
+
+import scala.util.Try
+
+
+object A

sbt-test/SeparateEachFileRewrite/test-1/expect/X1.scala

@@ -0,0 +1,11 @@
+package foo
+
+import scala.util.Try
+
+
+/**
+ * x1
+ */
+trait X1 {
+  def y: Try[Int]
+}

sbt-test/SeparateEachFileRewrite/test-1/expect/X2.scala

@@ -0,0 +1,12 @@
+package foo
+
+import scala.util.Try
+
+
+// x2 class
+class X2
+
+/**
+ * x2 object
+ */
+object X2

sbt-test/SeparateEachFileRewrite/test-1/project/plugins.sbt

@@ -0,0 +1 @@
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % sys.props("scalafix.version"))

sbt-test/SeparateEachFileRewrite/test-1/src/main/scala/foo/A.scala

@@ -0,0 +1,20 @@
+package foo
+
+import scala.util.Try
+
+/**
+ * x2 object
+ */
+object X2
+
+/**
+ * x1
+ */
+trait X1 {
+  def y: Try[Int]
+}
+
+// x2 class
+class X2
+
+object A

sbt-test/SeparateEachFileRewrite/test-1/test

@@ -0,0 +1,2 @@
+> scalafix SeparateEachFileRewrite
+> check