From 9f03217e1df458a3b674705b2748c415b7afd662 Mon Sep 17 00:00:00 2001
From: Tim Nieradzik <tim@sparse.tech>
Date: Sat, 13 Jul 2019 16:17:40 +0300
Subject: [PATCH] IDEA: Set language level for Scala library

This setting is required for IDEA to know whether certain
version-specific features are available (such as literal types in
2.13).
---
 src/main/scala/seed/generation/Idea.scala     |  7 +++---
 .../scala/seed/generation/util/IdeaFile.scala | 24 ++++++++++++++-----
 src/test/scala/seed/generation/IdeaSpec.scala | 13 ++++++++++
 3 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/src/main/scala/seed/generation/Idea.scala b/src/main/scala/seed/generation/Idea.scala
index 2367a52..08482a2 100644
--- a/src/main/scala/seed/generation/Idea.scala
+++ b/src/main/scala/seed/generation/Idea.scala
@@ -31,8 +31,7 @@ object Idea {
                    ): Unit = {
     val xml = IdeaFile.createLibrary(IdeaFile.Library(
       libraryJar.getFileName.toString,
-      isScalaCompiler = false,
-      compilerClasses = List(),
+      compilerInfo = None,
       classes = List(libraryJar.toAbsolutePath.toString),
       javaDoc = javaDocJar.toList.map(_.toAbsolutePath.toString),
       sources = sourcesJar.toList.map(_.toAbsolutePath.toString)))
@@ -122,8 +121,8 @@ object Idea {
 
       val xml = IdeaFile.createLibrary(IdeaFile.Library(
         name = build.project.scalaOrganisation + "-" + scalaVersion,
-        isScalaCompiler = true,
-        compilerClasses = scalaCompiler.compilerJars.map(_.toString),
+        compilerInfo = Some(IdeaFile.CompilerInfo(
+          scalaVersion, scalaCompiler.compilerJars.map(_.toString))),
         classes = scalaCompiler.fullClassPath.map(_.toString),
         javaDoc = List(),
         sources = List()))
diff --git a/src/main/scala/seed/generation/util/IdeaFile.scala b/src/main/scala/seed/generation/util/IdeaFile.scala
index cd92878..7d7f2cb 100644
--- a/src/main/scala/seed/generation/util/IdeaFile.scala
+++ b/src/main/scala/seed/generation/util/IdeaFile.scala
@@ -1,5 +1,7 @@
 package seed.generation.util
 
+import seed.generation.Bloop
+
 import pine._
 
 /** XML writers for IDEA files */
@@ -14,9 +16,10 @@ object IdeaFile {
                     moduleDeps: List[String],
                     output: Option[Output])
 
+  case class CompilerInfo(version: String, compilerClasses: List[String])
+
   case class Library(name: String,
-                     isScalaCompiler: Boolean,
-                     compilerClasses: List[String],
+                     compilerInfo: Option[CompilerInfo],
                      classes: List[String],
                      javaDoc: List[String],
                      sources: List[String])
@@ -83,11 +86,20 @@ object IdeaFile {
   }
 
   def createLibrary(library: Library): String = {
-    val tpe = if (library.isScalaCompiler) Some("Scala") else None
-    val compilerPaths = library.compilerClasses
-      .map(path => xml"""<root url="file://$path" />""")
+    val tpe = library.compilerInfo.map(_ => "Scala")
+    val languageLevel =
+      library.compilerInfo.map { case CompilerInfo(version, _) =>
+        val level = "Scala_" + Bloop.majorMinorVersion(version)
+          .replaceAllLiterally(".", "_")
+        xml"""<language-level>$level</language-level>"""
+      }.toList
+    val compilerPaths = library.compilerInfo.fold(List[pine.Tag[Singleton]]())(
+      _.compilerClasses.map(path => xml"""<root url="file://$path" />"""))
     val properties = if (compilerPaths.isEmpty) List() else List(xml"""
-      <properties><compiler-classpath>$compilerPaths</compiler-classpath></properties>
+      <properties>
+        $languageLevel
+        <compiler-classpath>$compilerPaths</compiler-classpath>
+      </properties>
     """)
     val classes = library.classes.map(path => xml"""<root url="jar://$path!/" />""")
     val javaDoc = library.javaDoc.map(path => xml"""<root url="jar://$path!/" />""")
diff --git a/src/test/scala/seed/generation/IdeaSpec.scala b/src/test/scala/seed/generation/IdeaSpec.scala
index 5b9534f..32ba603 100644
--- a/src/test/scala/seed/generation/IdeaSpec.scala
+++ b/src/test/scala/seed/generation/IdeaSpec.scala
@@ -108,6 +108,19 @@ object IdeaSpec extends SimpleTestSuite {
     assertEquals(profileNodes.head.attr("modules"),
       Some("module212,module211"))
 
+    val scalaLibrary2_11_11 =
+      pine.XmlParser.fromString(FileUtils.readFileToString(
+        ideaPath.resolve("libraries").resolve("org_scala_lang_2_11_11.xml").toFile,
+        "UTF-8"))
+    val scalaLibrary2_12_8 =
+      pine.XmlParser.fromString(FileUtils.readFileToString(
+        ideaPath.resolve("libraries").resolve("org_scala_lang_2_12_8.xml").toFile,
+        "UTF-8"))
+    assertEquals(scalaLibrary2_11_11.byTagAll["language-level"].map(_.toText),
+      List("Scala_2_11"))
+    assertEquals(scalaLibrary2_12_8.byTagAll["language-level"].map(_.toText),
+      List("Scala_2_12"))
+
     val module211 =
       pine.XmlParser.fromString(FileUtils.readFileToString(
         ideaPath.resolve("modules").resolve("module211.iml").toFile,