From 95c6a055bf2410044c398fc1a1f171a4e14ebe74 Mon Sep 17 00:00:00 2001
From: Katarzyna Marek <kasia@marek.net>
Date: Wed, 31 Jan 2024 18:15:03 +0100
Subject: [PATCH] bugfix: handle nested java jars

---
 .../internal/mtags/JavaToplevelMtags.scala    |  8 ++++
 .../internal/mtags/SymbolIndexBucket.scala    | 38 ++++++++++++++++++-
 .../test/scala/tests/DefinitionLspSuite.scala | 38 +++++++++++++++++++
 3 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/mtags/src/main/scala/scala/meta/internal/mtags/JavaToplevelMtags.scala b/mtags/src/main/scala/scala/meta/internal/mtags/JavaToplevelMtags.scala
index 1c1043af043..4c57145b317 100644
--- a/mtags/src/main/scala/scala/meta/internal/mtags/JavaToplevelMtags.scala
+++ b/mtags/src/main/scala/scala/meta/internal/mtags/JavaToplevelMtags.scala
@@ -27,6 +27,14 @@ class JavaToplevelMtags(val input: Input.VirtualFile) extends MtagsIndexer {
     }
   }
 
+  def readPackage: List[String] = {
+    fetchToken // start of file
+    fetchToken match {
+      case Token.Package => readPaths.map(_.value)
+      case _ => Nil
+    }
+  }
+
   private def loop: Unit = {
     val token = fetchToken
     token match {
diff --git a/mtags/src/main/scala/scala/meta/internal/mtags/SymbolIndexBucket.scala b/mtags/src/main/scala/scala/meta/internal/mtags/SymbolIndexBucket.scala
index 244029810aa..6e3d5cee52a 100644
--- a/mtags/src/main/scala/scala/meta/internal/mtags/SymbolIndexBucket.scala
+++ b/mtags/src/main/scala/scala/meta/internal/mtags/SymbolIndexBucket.scala
@@ -11,6 +11,7 @@ import scala.util.control.NonFatal
 import scala.meta.Dialect
 import scala.meta.internal.io.FileIO
 import scala.meta.internal.io.PathIO
+import scala.meta.internal.mtags.JavaToplevelMtags
 import scala.meta.internal.mtags.ScalametaCommonEnrichments._
 import scala.meta.internal.semanticdb.Scala._
 import scala.meta.internal.{semanticdb => s}
@@ -65,6 +66,8 @@ class SymbolIndexBucket(
           root.listRecursive.toList.flatMap {
             case source if source.isScala =>
               addSourceFile(source, None).map(sym => (sym, source))
+            case source if source.isJava =>
+              addJavaSourceFile(source).map(sym => (sym, source))
             case _ =>
               List.empty
           }
@@ -91,6 +94,33 @@ class SymbolIndexBucket(
     }
   }
 
+  /* Sometimes source jars have additional nested directories,
+   * in that case java toplevel is not "trivial".
+   * See: https://github.com/scalameta/metals/issues/3815
+   */
+  def addJavaSourceFile(source: AbsolutePath): List[String] = {
+    new JavaToplevelMtags(source.toInput).readPackage match {
+      case Nil => Nil
+      case packageParts =>
+        val className = source.filename.stripSuffix(".java")
+        val symbol = packageParts.mkString("", "/", s"/$className#")
+        if (
+          isTrivialToplevelSymbol(
+            source.toURI.toString,
+            symbol,
+            extension = "java"
+          )
+        ) Nil
+        else {
+          toplevels.updateWith(symbol) {
+            case Some(acc) => Some(acc + source)
+            case None => Some(Set(source))
+          }
+          List(symbol)
+        }
+    }
+  }
+
   def addSourceFile(
       source: AbsolutePath,
       sourceDirectory: Option[AbsolutePath]
@@ -121,9 +151,13 @@ class SymbolIndexBucket(
   // Returns true if symbol is com/foo/Bar# and path is /com/foo/Bar.scala
   // Such symbols are "trivial" because their definition location can be computed
   // on the fly.
-  private def isTrivialToplevelSymbol(path: String, symbol: String): Boolean = {
+  private def isTrivialToplevelSymbol(
+      path: String,
+      symbol: String,
+      extension: String = "scala"
+  ): Boolean = {
     val pathBuffer =
-      CharBuffer.wrap(path).subSequence(1, path.length - ".scala".length)
+      CharBuffer.wrap(path).subSequence(1, path.length - extension.length - 1)
     val symbolBuffer =
       CharBuffer.wrap(symbol).subSequence(0, symbol.length - 1)
     pathBuffer.equals(symbolBuffer)
diff --git a/tests/unit/src/test/scala/tests/DefinitionLspSuite.scala b/tests/unit/src/test/scala/tests/DefinitionLspSuite.scala
index b94044407b4..928dac4322e 100644
--- a/tests/unit/src/test/scala/tests/DefinitionLspSuite.scala
+++ b/tests/unit/src/test/scala/tests/DefinitionLspSuite.scala
@@ -714,4 +714,42 @@ class DefinitionLspSuite
     } yield ()
   }
 
+  test("nested-jars") {
+    cleanWorkspace()
+    for {
+      _ <- initialize(
+        s"""
+           |/metals.json
+           |{
+           |  "a": { 
+           |      "libraryDependencies": [
+           |        "com.daml:bindings-rxjava:2.0.0"
+           |      ]
+           |    }
+           |}
+           |/a/src/main/scala/a/Main.scala
+           |package a
+           |import com.daml.ledger.rxjava.DamlLedgerClient
+           |
+           |object O {
+           |  val k: DamlLedgerClient = ???
+           |}
+           |""".stripMargin
+      )
+      _ <- server.didOpen("a/src/main/scala/a/Main.scala")
+      _ = assertNoDiagnostics()
+      _ = assertNoDiff(
+        server.workspaceDefinitions,
+        """|/a/src/main/scala/a/Main.scala
+           |package a
+           |import com.daml.ledger.rxjava.DamlLedgerClient/*DamlLedgerClient.java*/
+           |
+           |object O/*L3*/ {
+           |  val k/*L4*/: DamlLedgerClient/*DamlLedgerClient.java*/ = ???/*Predef.scala*/
+           |}
+           |""".stripMargin,
+      )
+    } yield ()
+  }
+
 }