Fix #5223: Add tasty interpolator in IDE tests

This interpolator is used to defined virtual source files that will be
compiled before the test starts running. Unlike virtual source files
defined with `code`, the ones defined with `tasty` will not be opened in
the IDE (`textDocument/didOpen` will not be sent to the LSP server). As
a result, the language server will unpickle the trees from TASTY.

Fixes #5223

Author: Duhemm

language-server/test/dotty/tools/languageserver/DefinitionTest.scala

@@ -208,4 +208,15 @@ class DefinitionTest {
       .definition(m9 to m10, List(m3 to m4))
   }
 
+  @Test def definitionFromTasty: Unit = {
+    withSources(
+      tasty"""package mypackage
+              class ${m1}A${m2}""",
+      code"""package mypackage
+             object O {
+               new ${m3}A${m4}
+             }"""
+    ).definition(m3 to m4, List(m1 to m2))
+  }
+
 }

language-server/test/dotty/tools/languageserver/util/Code.scala

@@ -60,6 +60,17 @@ object Code {
       WorksheetWithPositions(text, positions)
     }
 
+    /**
+     * An interpolator similar to `code`, but used for defining a source that will
+     * be unpickled from TASTY.
+     *
+     * @see code
+     */
+    def tasty(args: Embedded*): TastyWithPositions = {
+      val (text, positions) = textAndPositions(args: _*)
+      TastyWithPositions(text, positions)
+    }
+
     private def textAndPositions(args: Embedded*): (String, List[(CodeMarker, Int, Int)]) = {
       val pi = sc.parts.iterator
       val ai = args.iterator
@@ -107,7 +118,10 @@ object Code {
 
   sealed trait SourceWithPositions {
 
-     /** The code contained within the virtual source file. */
+    /** A name for this source given its index. */
+    def sourceName(index: Int): String
+
+    /** The code contained within the virtual source file. */
     def text: String
 
     /** The positions of the markers that have been set. */
@@ -124,15 +138,29 @@ object Code {
    * @param text      The code contained within the virtual source file.
    * @param positions The positions of the markers that have been set.
    */
-  case class ScalaSourceWithPositions(text: String, positions: List[(CodeMarker, Int, Int)]) extends SourceWithPositions
+  case class ScalaSourceWithPositions(text: String, positions: List[(CodeMarker, Int, Int)]) extends SourceWithPositions {
+    def sourceName(index: Int): String = s"Source$index.scala"
+  }
 
   /**
    * A virtual worksheet where several markers have been set.
    *
    * @param text      The code contained within the virtual source file.
    * @param positions The positions of the markers that have been set.
    */
-  case class WorksheetWithPositions(text: String, positions: List[(CodeMarker, Int, Int)]) extends SourceWithPositions
+  case class WorksheetWithPositions(text: String, positions: List[(CodeMarker, Int, Int)]) extends SourceWithPositions {
+    def sourceName(index: Int): String = s"Worksheet$index.sc"
+  }
+
+  /**
+   * A virtual source file that will not be opened in the IDE, but instead unpickled from TASTY.
+   *
+   * @param text      The code contained within the virtual source file.
+   * @param positions The positions of the markers that have been set.
+   */
+  case class TastyWithPositions(text: String, positions: List[(CodeMarker, Int, Int)]) extends SourceWithPositions {
+    def sourceName(index: Int): String = s"Source-from-tasty-$index.scala"
+  }
 
   /**
    * A group of sources belonging to the same project.

language-server/test/dotty/tools/languageserver/util/CodeTester.scala

@@ -21,8 +21,8 @@ class CodeTester(workspaces: List[Workspace]) {
   private val files =
     for { workspace <- workspaces
           (source, id) <- workspace.sources.zipWithIndex } yield source match {
-      case ScalaSourceWithPositions(text, _) => testServer.openCode(text, workspace, s"Source$id.scala")
-      case WorksheetWithPositions(text, _) => testServer.openCode(text, workspace, s"Worksheet$id.sc")
+      case src @ TastyWithPositions(text, _) => testServer.openCode(text, workspace, src.sourceName(id), openInIDE = false)
+      case other => testServer.openCode(other.text, workspace, other.sourceName(id), openInIDE = true)
     }
 
   private val positions: PositionContext = getPositions(files)

language-server/test/dotty/tools/languageserver/util/server/TestServer.scala

@@ -10,7 +10,7 @@ import dotty.tools.dotc.Main
 import dotty.tools.dotc.reporting.{Reporter, ThrowingReporter}
 import dotty.tools.io.Directory
 import dotty.tools.languageserver.DottyLanguageServer
-import dotty.tools.languageserver.util.Code.Workspace
+import dotty.tools.languageserver.util.Code.{TastyWithPositions, Workspace}
 import org.eclipse.lsp4j.{ DidOpenTextDocumentParams, InitializeParams, InitializeResult, TextDocumentItem}
 
 class TestServer(testFolder: Path, workspaces: List[Workspace]) {
@@ -46,8 +46,12 @@ class TestServer(testFolder: Path, workspaces: List[Workspace]) {
           .map(elem => '"' + elem.toString.replace('\\', '/') + '"')
           .mkString("[ ", ", ", " ]")
 
-      // Compile all the dependencies of this workspace
-      workspace.dependsOn.foreach(compileWorkspaceAndDependencies)
+      if (workspace.sources.exists(_.isInstanceOf[TastyWithPositions])) {
+        compileWorkspaceAndDependencies(workspace)
+      } else {
+        // Compile all the dependencies of this workspace
+        workspace.dependsOn.foreach(compileWorkspaceAndDependencies)
+      }
 
       s"""{
          |  "id" : "${workspace.name}",
@@ -80,16 +84,21 @@ class TestServer(testFolder: Path, workspaces: List[Workspace]) {
   /** Open the code in the given file and returns the file.
    *  @param code code in file
    *  @param fileName file path in the source directory
+   *  @param openInIDE If true, send `textDocument/didOpen` to the server.
    *  @return the file opened
    */
-  def openCode(code: String, workspace: Workspace, fileName: String): TestFile = {
+  def openCode(code: String, workspace: Workspace, fileName: String, openInIDE: Boolean): TestFile = {
     val testFile = new TestFile(workspace.name + separator + fileName)
-    val dotdp = new DidOpenTextDocumentParams()
     val tdi = new TextDocumentItem()
     tdi.setUri(testFile.uri)
     tdi.setText(code)
-    dotdp.setTextDocument(tdi)
-    server.didOpen(dotdp)
+
+    if (openInIDE) {
+      val dotdp = new DidOpenTextDocumentParams()
+      dotdp.setTextDocument(tdi)
+      server.didOpen(dotdp)
+    }
+
     testFile
   }
 
@@ -127,7 +136,7 @@ class TestServer(testFolder: Path, workspaces: List[Workspace]) {
   private def compileWorkspace(workspace: Workspace): Unit = {
     val sourcesDir = sourceDirectory(workspace, wipe = true)
     val sources = workspace.sources.zipWithIndex.map { case (src, id) =>
-      val path = sourcesDir.resolve(s"Source${id}.scala").toAbsolutePath
+      val path = sourcesDir.resolve(src.sourceName(id)).toAbsolutePath
       Files.write(path, src.text.getBytes("UTF-8"))
       path.toString
     }