Adjust library folder path if Flatpak Steam

"~/.local/share/Steam" corresponds to a different directory inside a
Steam Flatpak. Ensure Protontricks doesn't mix them and try to look for
Flatpak Steam apps in the non-Flatpak installation directory.

Refs flathub/com.github.Matoking.protontricks#10

CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
  - Fix Wine crash when the Steam application and Protontricks are running at the same time
  - Fix Steam installation detection when both non-Flatpak and Flatpak versions of Steam are installed for the same user
  - Fix Protontricks crash when Proton installation is incomplete
+ - Fix Protontricks crash when both Flatpak and non-Flatpak versions of Steam are installed
 
 ## [1.7.0] - 2022-01-08
 ### Changed

src/protontricks/steam.py

@@ -681,11 +681,29 @@ def parse_library_folders(data):
         for value in library_entries:
             if isinstance(value, dict):
                 # Library data is stored in a dict in newer Steam releases
-                library_folders.append(Path(value["path"]))
+                path = Path(value["path"])
             else:
                 # Older releases just store the library path as a string
                 # and nothing else
-                library_folders.append(Path(value))
+                path = Path(value)
+
+            xdg_steam_path = Path.home() / ".local/share/Steam"
+            flatpak_steam_path = \
+                Path.home() / ".var/app/com.valvesoftware.Steam/data/Steam"
+
+            is_library_folder_xdg_steam = str(path) == str(xdg_steam_path)
+            is_flatpak_steam = str(steam_path) == str(flatpak_steam_path)
+
+            # Adjust the path if the library folder is "~/.local/share/Steam"
+            # and we're looking for library folders in
+            # "~/.var/app/com.valvesoftware.Steam"
+            # This is because ~/.local/share/Steam inside a Steam Flatpak
+            # sandbox corresponds to a different location, and we need to
+            # adjust for that.
+            if is_library_folder_xdg_steam and is_flatpak_steam:
+                path = flatpak_steam_path
+
+            library_folders.append(path)
 
         logger.info(
             "Found %d Steam library folders", len(library_folders)

tests/test_steam.py

@@ -289,6 +289,42 @@ def test_get_steam_lib_paths_duplicate_paths(
         assert steam_dir in library_paths
         assert library_dir in library_paths
 
+    def test_get_steam_lib_paths_adjust_flatpak_steam_path(
+            self, steam_dir, steam_library_factory, home_dir):
+        """
+        Retrieve Steam library folders and ensure that the
+        "~/.local/share/Steam" path is adjusted in the library folder
+        configuration file if Steam is installed using Flatpak.
+
+        Regression test for flathub/com.github.Matoking.protontricks#10
+        """
+        flatpak_steam_dir = \
+            home_dir / ".var/app/com.valvesoftware.Steam/data/Steam"
+        flatpak_steam_dir.mkdir(parents=True)
+        steam_dir.rename(str(flatpak_steam_dir))
+        shutil.rmtree(str(home_dir / ".local"))
+
+        libraryfolders_data = {
+            "libraryfolders": {
+                "0": {
+                    "path": str(home_dir / ".local/share/Steam")
+                }
+            }
+        }
+        (flatpak_steam_dir / "steamapps/libraryfolders.vdf").write_text(
+            vdf.dumps(libraryfolders_data), "utf-8"
+        )
+
+        library_paths = get_steam_lib_paths(
+            home_dir / ".var/app/com.valvesoftware.Steam/data/Steam"
+        )
+        # The only library folder should point under "~/.var/app", even if the
+        # path in the configuration file is "~/.local/share/Steam".
+        # This needs to be done to adjust for the different path in the
+        # Steam Flatpak sandbox.
+        assert len(library_paths) == 1
+        assert str(library_paths[0]) == str(flatpak_steam_dir)
+
 
 class TestFindAppidProtonPrefix:
     def test_find_appid_proton_prefix_steamapps_case(