From ca681744e920681b0f251037c25aaa85c5187985 Mon Sep 17 00:00:00 2001
From: Katarzyna Marek <kasia@marek.net>
Date: Tue, 2 Jan 2024 17:31:34 +0100
Subject: [PATCH] add back `compileAndLookForNewReferences`

---
 .../internal/metals/MetalsLspService.scala    | 61 ++++++++++++++++++-
 1 file changed, 59 insertions(+), 2 deletions(-)

diff --git a/metals/src/main/scala/scala/meta/internal/metals/MetalsLspService.scala b/metals/src/main/scala/scala/meta/internal/metals/MetalsLspService.scala
index 468011bd119..4ab534ea06c 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/MetalsLspService.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/MetalsLspService.scala
@@ -76,6 +76,7 @@ import scala.meta.internal.parsing.ClassFinder
 import scala.meta.internal.parsing.ClassFinderGranularity
 import scala.meta.internal.parsing.DocumentSymbolProvider
 import scala.meta.internal.parsing.FoldingRangeProvider
+import scala.meta.internal.parsing.TokenEditDistance
 import scala.meta.internal.parsing.Trees
 import scala.meta.internal.rename.RenameProvider
 import scala.meta.internal.semver.SemVer
@@ -1527,6 +1528,63 @@ class MetalsLspService(
       referencesResult(params).map(_.flatMap(_.locations).asJava)
     }
 
+  // Triggers a cascade compilation and tries to find new references to a given symbol.
+  // It's not possible to stream reference results so if we find new symbols we notify the
+  // user to run references again to see updated results.
+  private def compileAndLookForNewReferences(
+      params: ReferenceParams,
+      result: List[ReferencesResult],
+  ): Unit = {
+    val path = params.getTextDocument.getUri.toAbsolutePath
+    val old = path.toInputFromBuffers(buffers)
+    compilations.cascadeCompileFiles(Seq(path)).foreach { _ =>
+      val newBuffer = path.toInputFromBuffers(buffers)
+      val newParams: Option[ReferenceParams] =
+        if (newBuffer.text == old.text) Some(params)
+        else {
+          val edit = TokenEditDistance(old, newBuffer, trees)
+          edit
+            .getOrElse(TokenEditDistance.NoMatch)
+            .toRevised(
+              params.getPosition.getLine,
+              params.getPosition.getCharacter,
+            )
+            .foldResult(
+              pos => {
+                params.getPosition.setLine(pos.startLine)
+                params.getPosition.setCharacter(pos.startColumn)
+                Some(params)
+              },
+              () => Some(params),
+              () => None,
+            )
+        }
+      newParams match {
+        case None =>
+        case Some(p) =>
+          referencesProvider.references(p).foreach { newResult =>
+            val diff = newResult
+              .flatMap(_.locations)
+              .length - result.flatMap(_.locations).length
+            val diffSyms: Set[String] =
+              newResult.map(_.symbol).toSet -- result.map(_.symbol).toSet
+            if (diffSyms.nonEmpty && diff > 0) {
+              import scala.meta.internal.semanticdb.Scala._
+              val names =
+                diffSyms
+                  .map(sym => s"'${sym.desc.name.value}'")
+                  .mkString(" and ")
+              val message =
+                s"Found new symbol references for $names, try running again."
+              scribe.info(message)
+              statusBar
+                .addMessage(clientConfig.icons.info + message)
+            }
+          }
+      }
+    }
+  }
+
   def referencesResult(
       params: ReferenceParams
   ): Future[List[ReferencesResult]] = {
@@ -1544,8 +1602,7 @@ class MetalsLspService(
         }
       }
       if (results.nonEmpty) {
-        val path = params.getTextDocument.getUri.toAbsolutePath
-        compilations.cascadeCompileFiles(Seq(path))
+        compileAndLookForNewReferences(params, results)
       }
       results
     }