Fix Proton 11 prefix init hang, switch SLR to steamrt4

Proton 11's toolmanifest sets use_sessions=1, so the "run" verb forks
into a persistent session manager that never exits — prefix init hung
forever. Use "waitforexitandrun" instead. Also drop WINEDEBUG=-all so
init output is visible, and migrate the bundled Steam Linux Runtime
downloader from steamrt3/sniper to steamrt4 (Proton 11's required
runtime). SLR lookup paths fall back to sniper for users with an
existing install.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

5 files changed, 25 insertions, 15 deletions

diff --git a/src/src/prefixsetuprunner.cpp b/src/src/prefixsetuprunner.cpp
index bc1b9ce..53ab0bd 100644
--- a/src/src/prefixsetuprunner.cpp
+++ b/src/src/prefixsetuprunner.cpp
@@ -797,14 +797,16 @@ bool PrefixSetupRunner::stepProtonInit()
   env["SteamGameId"]                      = QString::number(m_appId);
   env["DISPLAY"]                          = "";
   env["WAYLAND_DISPLAY"]                  = "";
-  env["WINEDEBUG"]                        = "-all";
   env["WINEDLLOVERRIDES"] = "msdia80.dll=n;conhost.exe=d;cmd.exe=d";
 
   emit logMessage("Initializing Wine prefix with Proton...");
 
   QByteArray protonOutput;
+  // waitforexitandrun (not "run") is required for Proton 11+ which uses
+  // use_sessions=1 — a plain "run" forks into a session manager that never
+  // exits, hanging prefix init.
   const int rc = runProcess(protonScript,
-                            {"run", "wineboot", "-u"},
+                            {"waitforexitandrun", "wineboot", "-u"},
                             env, -1, &protonOutput);
   if (rc != 0) {
     // Detect a broken Proton install: setup_prefix copies DLLs from Proton's
@@ -1692,15 +1694,22 @@ QString PrefixSetupRunner::detectSteamPath() const
 
 QString PrefixSetupRunner::detectSLRRunScript() const
 {
-  // Check NaK-downloaded SLR first.
-  const QString nakSlr = fluorineDataDir() + "/steamrt/SteamLinuxRuntime_sniper/run";
-  if (QFileInfo::exists(nakSlr))
-    return nakSlr;
+  // Check Fluorine-downloaded SLR first (steamrt4 preferred, sniper fallback).
+  const QStringList nakCandidates = {
+      fluorineDataDir() + "/steamrt/SteamLinuxRuntime_4/run",
+      fluorineDataDir() + "/steamrt/SteamLinuxRuntime_sniper/run",
+  };
+  for (const QString& p : nakCandidates) {
+    if (QFileInfo::exists(p))
+      return p;
+  }
 
   const QString steamPath = detectSteamPath();
 
   const QStringList candidates = {
+      steamPath + "/steamapps/common/SteamLinuxRuntime_4/run",
       steamPath + "/steamapps/common/SteamLinuxRuntime_sniper/run",
+      QDir::homePath() + "/.local/share/Steam/steamapps/common/SteamLinuxRuntime_4/run",
       QDir::homePath() + "/.local/share/Steam/steamapps/common/SteamLinuxRuntime_sniper/run",
       "/usr/lib/pressure-vessel/wrap",
   };
diff --git a/src/src/protonlauncher.cpp b/src/src/protonlauncher.cpp
index 4e9ed4d..976eed7 100644
--- a/src/src/protonlauncher.cpp
+++ b/src/src/protonlauncher.cpp
@@ -135,18 +135,19 @@ QString detectSteamPath()
   return {};
 }
 
-// Find the Steam Linux Runtime (sniper) run script.
+// Find the Steam Linux Runtime run script (steamrt4 preferred, sniper fallback).
 // SLR wraps the Proton launch in a pressure-vessel container that provides
 // GStreamer, 32-bit libs, and an FHS-compliant environment — required on
-// NixOS and other non-FHS distros.
+// NixOS and other non-FHS distros. Proton 11+ requires steamrt4.
 // Returns empty string if SLR is not installed.
 QString detectSLRRunScript()
 {
   const QString steamPath = detectSteamPath();
 
-  // Common SLR sniper locations relative to Steam install
   const QStringList candidates = {
+      steamPath + "/steamapps/common/SteamLinuxRuntime_4/run",
       steamPath + "/steamapps/common/SteamLinuxRuntime_sniper/run",
+      QDir::home().filePath(".local/share/Steam/steamapps/common/SteamLinuxRuntime_4/run"),
       QDir::home().filePath(".local/share/Steam/steamapps/common/SteamLinuxRuntime_sniper/run"),
       "/usr/lib/pressure-vessel/wrap",
   };
diff --git a/src/src/settingsdialog.ui b/src/src/settingsdialog.ui
index cb158f2..4e10085 100644
--- a/src/src/settingsdialog.ui
+++ b/src/src/settingsdialog.ui
@@ -1799,7 +1799,7 @@ If you disable this feature, MO will only display official DLCs this way. Please
              <string>Download Steam Linux Runtime</string>
             </property>
             <property name="toolTip">
-             <string>Download SteamLinuxRuntime_sniper (~180 MB) from Valve's servers. Provides GStreamer, 32-bit libs, and an FHS environment for non-FHS distros (NixOS, etc.). Required for the "Use SLR" option in the Instance Manager.</string>
+             <string>Download SteamLinuxRuntime_4 (steamrt4, ~200 MB) from Valve's servers. Provides GStreamer, 32-bit libs, and an FHS environment for non-FHS distros (NixOS, etc.). Required for the "Use SLR" option in the Instance Manager and for Proton 11+.</string>
             </property>
            </widget>
           </item>
diff --git a/src/src/slrmanager.cpp b/src/src/slrmanager.cpp
index fe60e56..94e4cbf 100644
--- a/src/src/slrmanager.cpp
+++ b/src/src/slrmanager.cpp
@@ -12,9 +12,9 @@
 
 namespace {
 
-const char* BASE_URL     = "https://repo.steampowered.com/steamrt3/images/latest-public-beta";
-const char* ARCHIVE_NAME = "SteamLinuxRuntime_sniper.tar.xz";
-const char* EXTRACTED_DIR = "SteamLinuxRuntime_sniper";
+const char* BASE_URL     = "https://repo.steampowered.com/steamrt4/images/latest-public-beta";
+const char* ARCHIVE_NAME = "SteamLinuxRuntime_4.tar.xz";
+const char* EXTRACTED_DIR = "SteamLinuxRuntime_4";
 
 QString slrInstallDir()
 {
@@ -147,7 +147,7 @@ QString downloadSlr(const std::function<void(float)>& progressCb,
   const QString archivePath = installDir + "/" + ARCHIVE_NAME;
 
   // 2. Download.
-  status(QStringLiteral("Downloading Steam Linux Runtime (sniper, ~180 MB)..."));
+  status(QStringLiteral("Downloading Steam Linux Runtime (steamrt4, ~200 MB)..."));
   httpGet(QStringLiteral("%1/%2").arg(QLatin1String(BASE_URL), QLatin1String(ARCHIVE_NAME)),
           cancelFlag, progress, archivePath);
   progress(1.0f);
diff --git a/src/src/slrmanager.h b/src/src/slrmanager.h
index c800c2e..e0a1b3f 100644
--- a/src/src/slrmanager.h
+++ b/src/src/slrmanager.h
@@ -10,7 +10,7 @@ __attribute__((visibility("default"))) bool isSlrInstalled();
 /// Returns the path to the SLR `run` script, or empty if not installed.
 __attribute__((visibility("default"))) QString getSlrRunScript();
 
-/// Download and install SteamLinuxRuntime_sniper (~180 MB).
+/// Download and install SteamLinuxRuntime_4 (steamrt4, ~200 MB).
 /// Skips if already at the latest version (BUILD_ID check).
 /// Returns empty string on success, or an error message.
 __attribute__((visibility("default")))