commit d4c899cede0743d40934ca11f83691cda72ff9dd
Author: Carles Pastor <cpbadosa@gmail.com>
Date:   Sat Apr 2 20:47:06 2022 +0200

    Detect when running inside a flatpak sandbox

diff --git a/Source/Core/UICommon/UICommon.cpp b/Source/Core/UICommon/UICommon.cpp
index cb857fd3c7..e3ddde24fb 100644
--- a/Source/Core/UICommon/UICommon.cpp
+++ b/Source/Core/UICommon/UICommon.cpp
@@ -309,24 +309,25 @@ void SetUserDirectory(std::string custom_path)
     // We are on a non-Apple and non-Android POSIX system, there are 4 cases:
     // 1. GetExeDirectory()/portable.txt exists
     //    -> Use GetExeDirectory()/User
-    // 2. $DOLPHIN_EMU_USERPATH is set
+    // 2. $DOLPHIN_EMU_USERPATH is set, and we're not in flatpak
     //    -> Use $DOLPHIN_EMU_USERPATH
-    // 3. ~/.dolphin-emu directory exists
+    // 3. ~/.dolphin-emu directory exists, and we're not in flatpak
     //    -> Use ~/.dolphin-emu
     // 4. Default
     //    -> Use XDG basedir, see
     //    http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
     user_path = home_path + "." DOLPHIN_DATA_DIR DIR_SEP;
     std::string exe_path = File::GetExeDirectory();
+    bool flatpak = File::Exists("/.flatpak-info");
     if (File::Exists(exe_path + DIR_SEP "portable.txt"))
     {
       user_path = exe_path + DIR_SEP "User" DIR_SEP;
     }
-    else if (env_path)
+    else if (env_path && !flatpak)
     {
       user_path = env_path;
     }
-    else if (!File::Exists(user_path))
+    else if (flatpak || !File::Exists(user_path))
     {
       const char* data_home = getenv("XDG_DATA_HOME");
       std::string data_path =