Automatically add Scala library if it's not added explicitly

integrations/maven-bloop/src/main/scala/bloop/integrations/maven/MojoImplementation.scala

@@ -107,7 +107,7 @@ object MojoImplementation {
       .getReactorProjects()
       .asScala
       .map { project =>
-        (project.getGroupId(), project.getName(), project.getVersion())
+        (project.getGroupId(), project.getArtifactId(), project.getVersion())
       }
       .toSet
 
@@ -172,10 +172,29 @@ object MojoImplementation {
       val analysisOut = None
       val sourceDirs = sourceDirs0.map(abs).toList
       val classesDir = abs(classesDir0)
+      val artifacts = project.getArtifacts().asScala
+      lazy val libraryAndDependencies = scalaContext.toList
+        .flatMap(_.findLibraryAndDependencies().asScala)
 
+      // if we don't add scala-library explicitely it will not be available in artifacts
+      val hasScalaLibrary = artifacts.exists {
+        case a: Artifact => a.getArtifactId() == "scala-library"
+      }
+      val allArtifacts = if (hasScalaLibrary) artifacts else artifacts ++ libraryAndDependencies
       val modules =
-        project.getArtifacts().asScala.collect {
+        allArtifacts.collect {
           case art: Artifact if art.getType() == "jar" && isNotReactorProjectArtifact(art) =>
+            if (art.getArtifactId() == "scala-library")
+              scalaContext match {
+                case Some(context) =>
+                  /* If the scala library is not specified explicitely as recommended
+                   * it might sometimes be wrong, this doesn't happen for Scala 3.
+                   */
+                  val scalaVersion = context.version().toString()
+                  if (!scalaVersion.startsWith("3.") && scalaVersion != art.getVersion())
+                    art.setVersion(context.version.toString)
+                case _ =>
+              }
             resolveArtifact(art).foreach { resolvedFile =>
               //since we don't resolve dependencies automatically in the plugin, this will be null
               art.setFile(resolvedFile)
@@ -195,7 +214,12 @@ object MojoImplementation {
         }
 
         val cp = classpath0().asScala.toList.asInstanceOf[List[String]].map(u => abs(new File(u)))
-        (projectDependencies.map(u => abs(new File(u))) ++ cp).toList
+        // scalaLibrary might not be added by default to classpath and it's needed for the compilation
+        val hasScalaLibrary = cp.exists(p => p.toFile().getName().contains("scala_library-"))
+
+        val fullClasspath =
+          if (hasScalaLibrary) cp else cp ++ libraryAndDependencies.map(_.getFile().toPath())
+        (projectDependencies.map(u => abs(new File(u))) ++ fullClasspath).toList
       }
 
       val tags = if (configuration == "test") List(Tag.Test) else List(Tag.Library)
@@ -284,6 +308,8 @@ object MojoImplementation {
     } else {
       Nil
     }
+    if (artifact.getFile() == null)
+      throw new IllegalArgumentException(s"Could not resolve $artifact")
     Config.Module(
       organization = artifact.getGroupId(),
       name = artifact.getArtifactId(),

integrations/maven-bloop/src/test/resources/no_library/pom.xml

@@ -0,0 +1,43 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.example</groupId>
+  <artifactId>no_library</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <name>No library</name>
+  <description>A minimal Scala project using the Maven build tool.</description>
+
+  <properties>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+    <encoding>UTF-8</encoding>
+    <scala.version>2.13.6</scala.version>
+  </properties>
+
+  <dependencies>
+  </dependencies>
+
+  <build>
+    <sourceDirectory>src/main/scala</sourceDirectory>
+    <testSourceDirectory>src/test/scala</testSourceDirectory>
+    <plugins>
+      <plugin>
+        <!-- see http://davidb.github.com/scala-maven-plugin -->
+        <groupId>net.alchim31.maven</groupId>
+        <artifactId>scala-maven-plugin</artifactId>
+        <version>4.1.1</version>
+        <configuration></configuration>
+        <executions>
+          <execution>
+            <goals>
+              <goal>compile</goal>
+              <goal>testCompile</goal>
+            </goals>
+            <configuration>
+              <scalaVersion>${scala.version}</scalaVersion>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

integrations/maven-bloop/src/test/scala/bloop/integrations/maven/MavenConfigGenerationSuite.scala

@@ -155,6 +155,27 @@ class MavenConfigGenerationSuite extends BaseConfigSuite {
     }
   }
 
+  @Test
+  def noLibrary() = {
+    check("no_library/pom.xml") { (configFile, projectName, subprojects) =>
+      assert(subprojects.isEmpty)
+      assert(configFile.project.`scala`.isDefined)
+      assertEquals("2.13.6", configFile.project.`scala`.get.version)
+      assertEquals("org.scala-lang", configFile.project.`scala`.get.organization)
+      assert(configFile.project.`scala`.get.jars.exists(_.toString.contains("scala-compiler")))
+      assert(hasCompileClasspathEntryName(configFile, "scala-library"))
+      assert(hasTag(configFile, Tag.Library))
+      assertNoConfigsHaveAnyJars(List(configFile), List(s"$projectName", s"$projectName-test"))
+
+      val resolutionModules = configFile.project.resolution.get.modules
+      val scalaLibraryModule = resolutionModules.find(_.name == "scala-library")
+      assert(scalaLibraryModule.exists { m =>
+        m.artifacts.exists(_.path.toString().contains("scala-library-2.13.6-sources.jar"))
+        m.artifacts.exists(_.path.toString().contains("scala-library-2.13.6.jar"))
+      })
+    }
+  }
+
   private def check(testProject: String, submodules: List[String] = Nil)(
       checking: (Config.File, String, List[Config.File]) => Unit
   ): Unit = {