Merge pull request #7948 from eed3si9n/wip/java-home

[2.x] fix: Use JDK path, not JRE path

internal/util-core/src/main/scala/sbt/internal/util/Util.scala

@@ -8,11 +8,12 @@
 
 package sbt.internal.util
 
+import java.nio.file.{ Path, Paths }
 import java.util.Locale
 
 import scala.collection.concurrent.TrieMap
 
-object Util {
+object Util:
   def makeList[T](size: Int, value: T): List[T] = List.fill(size)(value)
 
   def separate[T, A, B](ps: Seq[T])(f: T => Either[A, B]): (Seq[A], Seq[B]) = {
@@ -78,4 +79,11 @@ object Util {
     val cache = TrieMap.empty[A1, A2]
     x => cache.getOrElseUpdate(x, f(x))
   }
-}
+
+  lazy val javaHome: Path =
+    sys.env.get("JAVA_HOME") match
+      case Some(home) => Paths.get(home)
+      case None =>
+        if sys.props("java.home").endsWith("jre") then Paths.get(sys.props("java.home")).getParent()
+        else Paths.get(sys.props("java.home"))
+end Util

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

@@ -9,7 +9,7 @@
 package sbt
 
 import java.io.{ File, PrintWriter }
-import java.nio.file.{ Files, Paths, Path => NioPath }
+import java.nio.file.{ Files, Path => NioPath }
 import java.util.Optional
 import java.util.concurrent.TimeUnit
 import lmcoursier.CoursierDependencyResolution
@@ -245,13 +245,12 @@ object Defaults extends BuildCommon {
     val base = app.baseDirectory.getCanonicalFile.toPath
     val boot = app.provider.scalaProvider.launcher.bootDirectory.toPath
     val ih = app.provider.scalaProvider.launcher.ivyHome.toPath
-    val javaHome = Paths.get(sys.props("java.home"))
     ListMap(
       "OUT" -> out,
       "BASE" -> base,
       "SBT_BOOT" -> boot,
       "IVY_HOME" -> ih,
-      "JAVA_HOME" -> javaHome
+      "JAVA_HOME" -> Util.javaHome,
     )
 
   private[sbt] lazy val globalIvyCore: Seq[Setting[?]] =

main/src/main/scala/sbt/internal/Load.scala

@@ -33,7 +33,7 @@ import xsbti.{ FileConverter, HashedVirtualFileRef, VirtualFile }
 import xsbti.compile.{ ClasspathOptionsUtil, Compilers }
 import java.io.File
 import java.net.URI
-import java.nio.file.{ Path, Paths }
+import java.nio.file.Path
 import scala.annotation.tailrec
 import scala.collection.mutable
 import sbt.internal.util.Util
@@ -71,7 +71,7 @@ private[sbt] object Load {
     val scalaProvider = app.provider.scalaProvider
     val launcher = scalaProvider.launcher
     val stagingDirectory = getStagingDirectory(state, globalBase).getCanonicalFile
-    val javaHome = Paths.get(sys.props("java.home"))
+    val javaHome = Util.javaHome
     val out = baseDirectory.toPath.resolve("target").resolve("out")
     val rootPaths = Map(
       "OUT" -> out,

protocol/src/main/scala/sbt/internal/bsp/BuildServerConnection.scala

@@ -9,6 +9,7 @@
 package sbt.internal.bsp
 
 import sbt.internal.bsp.codec.JsonProtocol.BspConnectionDetailsFormat
+import sbt.internal.util.Util
 import sbt.io.IO
 import sjsonnew.support.scalajson.unsafe.{ CompactPrinter, Converter }
 
@@ -25,7 +26,7 @@ object BuildServerConnection {
 
   private[sbt] def writeConnectionFile(sbtVersion: String, baseDir: File): Unit = {
     val bspConnectionFile = new File(baseDir, ".bsp/sbt.json")
-    val javaHome = System.getProperty("java.home")
+    val javaHome = Util.javaHome
     val classPath = System.getProperty("java.class.path")
 
     val sbtScript = Option(System.getProperty("sbt.script"))

server-test/src/test/scala/testpkg/BuildServerTest.scala

@@ -234,7 +234,6 @@ class BuildServerTest extends AbstractServerTest {
     val buildTarget = buildTargetUri("javaProj", "Compile")
 
     compile(buildTarget)
-
     assertMessage(
       "build/publishDiagnostics",
       "Hello.java",
@@ -257,16 +256,17 @@ class BuildServerTest extends AbstractServerTest {
     val testFile = new File(svr.baseDirectory, s"java-proj/src/main/java/example/Hello.java")
 
     val otherBuildFile = new File(svr.baseDirectory, "force-java-out-of-process-compiler.sbt")
-    // Setting `javaHome` will force SBT to shell out to an external Java compiler instead
+    // Setting `javaHome` will force sbt to shell out to an external Java compiler instead
     // of using the local compilation service offered by the JVM running this SBT instance.
     IO.write(
       otherBuildFile,
       """
+        |def jdk: File = sbt.internal.Util.javaHome.toFile()
         |lazy val javaProj = project
         |  .in(file("java-proj"))
         |  .settings(
         |    javacOptions += "-Xlint:all",
-        |    javaHome := Some(file(System.getProperty("java.home")))
+        |    javaHome := Some(jdk)
         |  )
         |""".stripMargin
     )
@@ -278,16 +278,17 @@ class BuildServerTest extends AbstractServerTest {
       "build/publishDiagnostics",
       "Hello.java",
       """"severity":2""",
-      """found raw type: List"""
-    )(message = "should send publishDiagnostics with severity 2 for Hello.java")
+      """found raw type"""
+    )(message = "should send publishDiagnostics with severity 2 for Hello.java", debug = false)
 
     assertMessage(
       "build/publishDiagnostics",
       "Hello.java",
       """"severity":1""",
-      """incompatible types: int cannot be converted to String"""
+      """incompatible types: int cannot be converted"""
     )(
-      message = "should send publishDiagnostics with severity 1 for Hello.java"
+      message = "should send publishDiagnostics with severity 1 for Hello.java",
+      debug = true
     )
     // Note the messages changed slightly in both cases. That's interesting…
 
@@ -690,9 +691,14 @@ class BuildServerTest extends AbstractServerTest {
     def assertion =
       svr.waitForString(duration) { msg =>
         if (debug) println(msg)
+        if debug then
+          parts.foreach: p =>
+            if msg.contains(p) then println(s"> $msg contains $p")
+            else ()
         parts.forall(msg.contains)
       }
-    if (message.nonEmpty) assert(assertion, message) else assert(assertion)
+    if message.nonEmpty then assert(assertion, message)
+    else assert(assertion)
   }
 
   private def reloadWorkspace(): Int =