From 08867f9c33273ec505395764f82f288abb807e35 Mon Sep 17 00:00:00 2001
From: Jakub Ciesluk <323892@uwr.edu.pl>
Date: Fri, 3 Nov 2023 13:47:10 +0100
Subject: [PATCH] bugfix: Add output classes directory to classpath for PC

It was there already for bloop and sbt, but not for mill. Because of this, presentation compiler didn't see symbols from workspace.
---
 .../internal/metals/MetalsEnrichments.scala   |  8 ++-
 .../scala/tests/mill/MillServerSuite.scala    | 54 +++++++++++++++++++
 2 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/metals/src/main/scala/scala/meta/internal/metals/MetalsEnrichments.scala b/metals/src/main/scala/scala/meta/internal/metals/MetalsEnrichments.scala
index 9260bec34eb..36c9f258afc 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/MetalsEnrichments.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/MetalsEnrichments.scala
@@ -1015,8 +1015,12 @@ object MetalsEnrichments
         .map(_.stripPrefix(flag))
     }
 
-    def classpath: List[String] =
-      item.getClasspath.asScala.toList
+    def classpath: List[String] = {
+      val outputClasses = item.getClassDirectory
+      val classes = item.getClasspath.asScala.toList
+      if (classes.contains(outputClasses)) classes
+      else outputClasses :: classes
+    }
 
     def jarClasspath: List[AbsolutePath] =
       classpath
diff --git a/tests/slow/src/test/scala/tests/mill/MillServerSuite.scala b/tests/slow/src/test/scala/tests/mill/MillServerSuite.scala
index aa37ce29641..71d18cad900 100644
--- a/tests/slow/src/test/scala/tests/mill/MillServerSuite.scala
+++ b/tests/slow/src/test/scala/tests/mill/MillServerSuite.scala
@@ -118,4 +118,58 @@ class MillServerSuite
       }
     }
   }
+
+  test(s"presentation-compiler") {
+    def millBspConfig = workspace.resolve(".bsp/mill-bsp.json")
+    writeLayout(
+      s"""
+         |/.mill-version
+         |$supportedBspVersion
+         |/build.sc
+         |import mill._, scalalib._
+         |object foo extends ScalaModule {
+         |  def scalaVersion = "${V.scala213}"
+         |}
+         |/foo/src/Main.scala
+         |package foo
+         |
+         |import foo.A
+         |object Main extends App {
+         |  println(A.msg)
+         |}
+         |
+         |/foo/src/A.scala
+         |package foo
+         |
+         |object A {
+         |  def msg = "Hello"
+         |}
+         |""".stripMargin
+    )
+    for {
+      _ <- server.initialize()
+      _ <- server.initialized()
+      _ = assertNoDiff(
+        client.workspaceMessageRequests,
+        importBuildMessage,
+      )
+      _ = client.messageRequests.clear() // restart
+      _ = assert(!millBspConfig.exists)
+      _ = server.server.buildServerPromise = Promise()
+      _ <- server.executeCommand(ServerCommands.GenerateBspConfig)
+      _ <- server.server.buildServerPromise.future
+      _ = assert(millBspConfig.exists)
+      _ = server.assertBuildServerConnection()
+      _ <- server.didOpen("foo/src/Main.scala")
+      _ <- server.assertHoverAtLine(
+        "foo/src/Main.scala",
+        "println(A.m@@sg)",
+        """|```scala
+           |def msg: String
+           |```
+           |""".stripMargin,
+      )
+
+    } yield {}
+  }
 }