From 4347ad4ccf869c6d87da8f81e96698caf0e9a634 Mon Sep 17 00:00:00 2001
From: Katarzyna Marek <kasia@marek.net>
Date: Mon, 16 Oct 2023 12:05:08 +0200
Subject: [PATCH] bugfix: add user config promise

---
 .../meta/internal/metals/MetalsLspService.scala     | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 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 11df0204c71..aa44e3e2c7e 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/MetalsLspService.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/MetalsLspService.scala
@@ -137,6 +137,7 @@ class MetalsLspService(
 
   @volatile
   private var userConfig: UserConfiguration = initialUserConfig
+  private val userConfigPromise: Promise[Unit] = Promise()
 
   ThreadPools.discardRejectedRunnables("MetalsLanguageServer.sh", sh)
   ThreadPools.discardRejectedRunnables("MetalsLanguageServer.ec", ec)
@@ -926,6 +927,7 @@ class MetalsLspService(
   }
 
   def setUserConfig(newConfig: UserConfiguration): UserConfiguration = {
+    userConfigPromise.trySuccess(())
     val old = userConfig
     userConfig = newConfig
     old
@@ -1548,10 +1550,13 @@ class MetalsLspService(
       params: SemanticTokensParams
   ): CompletableFuture[SemanticTokens] = {
     CancelTokens.future { token =>
-      compilers.semanticTokens(params, token).map { semanticTokens =>
-        if (semanticTokens.getData().isEmpty()) null
-        else semanticTokens
-      }
+      for {
+        _ <- userConfigPromise.future
+        res <- compilers.semanticTokens(params, token).map { semanticTokens =>
+          if (semanticTokens.getData().isEmpty()) null
+          else semanticTokens
+        }
+      } yield res
     }
   }