From 881ea95f148511b629b0b92653745b8bc678f8a1 Mon Sep 17 00:00:00 2001
From: Ariel Juodziukynas <arieljuod@gmail.com>
Date: Sat, 1 Mar 2025 16:24:12 -0300
Subject: [PATCH] [UX/Fix] Respect experimental UMU support disabled (#4191)

* Respect experimental UMU config after new default change

* umuSupport experimental feature optional

* fix comparison of disableUMU check

* fix default `disableUMU` config for new games and old games
---
 src/backend/game_config.ts                |  4 ++++
 src/backend/utils/compatibility_layers.ts | 17 ++++++++++++++++-
 src/common/types.ts                       |  1 +
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/backend/game_config.ts b/src/backend/game_config.ts
index f116e149af..5678c09c6c 100644
--- a/src/backend/game_config.ts
+++ b/src/backend/game_config.ts
@@ -277,6 +277,10 @@ class GameConfigV0 extends GameConfig {
       // read game's settings
       const settings = JSON.parse(readFileSync(this.path, 'utf-8'))
       gameSettings = settings[this.appName] || ({} as GameSettings)
+    } else {
+      // only set the `disableUMU` default value when getting settings for a new game
+      // we want it to be `undefined` for games that were installed already
+      defaultSettings.disableUMU = false
     }
 
     if (!isWindows) {
diff --git a/src/backend/utils/compatibility_layers.ts b/src/backend/utils/compatibility_layers.ts
index d128bccc8e..f8118f827c 100644
--- a/src/backend/utils/compatibility_layers.ts
+++ b/src/backend/utils/compatibility_layers.ts
@@ -559,7 +559,22 @@ export async function isUmuSupported(
 ): Promise<boolean> {
   if (!isLinux) return false
   if (gameSettings.wineVersion.type !== 'proton') return false
-  if (gameSettings.disableUMU) return false
+  if (gameSettings.disableUMU === true) return false
+  if (gameSettings.disableUMU === undefined) {
+    // If the disableUMU setting is undefined it means the game was installed and configured
+    // before the introduction of this setting, so the usage of UMU was dictated by the
+    // experimental feature configuration.
+    //
+    // We have to check this to not enable UMU incorrectly even if the setting is not editable
+    // anymore.
+    // If we don't, we would end up enabling UMU for games that are already functional with proton
+    // without UMU to not mess their prefix
+    const experimentalFeatures =
+      GlobalConfig.get().getSettings().experimentalFeatures
+
+    // if UMU was never enabled or was enabled and then disabled
+    if (!experimentalFeatures?.umuSupport) return false
+  }
   if (!checkUmuInstalled) return true
   if (!existsSync(await getUmuPath())) return false
 
diff --git a/src/common/types.ts b/src/common/types.ts
index 51e3570b35..aa88a9272c 100644
--- a/src/common/types.ts
+++ b/src/common/types.ts
@@ -66,6 +66,7 @@ export type ExperimentalFeatures = {
   enableNewDesign: boolean
   enableHelp: boolean
   cometSupport: boolean
+  umuSupport?: boolean
 }
 
 export interface AppSettings extends GameSettings {