Check for incomplete Proton installation

Incomplete Proton installations where the `dist` directory does not
exist yet cause Protontricks to crash. Check for this and instruct the
user to launch a Steam app at least once to ensure the installation is
complete.

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

CHANGELOG.md

@@ -9,6 +9,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Fixed
  - 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
 
 ## [1.7.0] - 2022-01-08
 ### Changed

src/protontricks/cli/main.py

@@ -267,6 +267,13 @@ def exit_(error):
     if not proton_app:
         exit_("Proton installation could not be found!")
 
+    if not proton_app.is_proton_ready:
+        exit_(
+            "Proton installation is incomplete. Have you launched a Steam app "
+            "using this Proton version at least once to finish the "
+            "installation?"
+        )
+
     # If neither search or GUI are set, do a normal Winetricks command
     # Find game by appid
     steam_appid = int(args.appid)

src/protontricks/steam.py

@@ -129,6 +129,16 @@ def is_windows_app(self):
         """
         return not self.is_proton and self.prefix_path_exists and self.appid
 
+    @property
+    def is_proton_ready(self):
+        """
+        Return True if the Proton installation is ready for use.
+
+        Proton installation might be incomplete if it hasn't been launched
+        yet, in which case the Proton binaries don't exist yet.
+        """
+        return bool(self.proton_dist_path)
+
     @property
     def proton_dist_path(self):
         """

tests/cli/test_main.py

@@ -405,6 +405,25 @@ def test_run_compat_tool_not_proton(
             record.getMessage()
         )
 
+    def test_run_command_proton_incomplete(
+            self, cli, steam_app_factory, default_proton):
+        """
+        Try performing a Protontricks command using a Proton installation that
+        is incomplete because it hasn't been launched yet.
+
+        Regression test for
+        https://github.com/flathub/com.github.Matoking.protontricks/issues/10
+        """
+        # Remove the 'dist' directory to make the Proton installation
+        # incomplete
+        shutil.rmtree(str(default_proton.install_path / "dist"))
+
+        steam_app_factory(name="Fake game", appid=10)
+
+        result = cli(["10", "winecfg"], expect_returncode=1)
+
+        assert "Proton installation is incomplete" in result
+
     def test_run_command_runtime_incomplete(
             self, cli, steam_app_factory, steam_runtime_soldier,
             command, proton_factory, steam_dir):