Skip unidentifiable icon files

Pillow cannot parse all image files (usually JPEG). This might be due to
the files not being valid image files in the first place, or Pillow not
being able to parse them. In any case, skip the file and log the error
if the image file cannot be parsed.

Fixes #264
Fixes #268

CHANGELOG.md

@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Fixed
  - Fix Protontricks not recognizing supported Steam Runtime installation due to changed name
  - Fix Protontricks not recognizing default Proton installation for games with different Proton preselected by Valve testing
+ - Fix Protontricks crash when app has an unidentifiable app icon
 
 ## [1.10.5] - 2023-09-05
 ### Fixed

src/protontricks/gui.py

@@ -96,19 +96,21 @@ def _get_appid2icon(steam_apps):
                             "App icon %s has unusual size, resizing",
                             app.icon_path
                         )
-                        try:
-                            resized_img = img.resize(APP_ICON_SIZE).convert("RGB")
-                            resized_img.save(icon_cache_path)
-                            final_icon_path = icon_cache_path
-                        except Exception:
-                            logger.warning(
-                                "Could not resize %s, ignoring",
-                                app.icon_path,
-                                exc_info=True
-                            )
+                        resized_img = img.resize(APP_ICON_SIZE).convert("RGB")
+                        resized_img.save(icon_cache_path)
+                        final_icon_path = icon_cache_path
             except FileNotFoundError:
                 # Icon does not exist, the placeholder will be used
                 pass
+            except Exception:
+                # Multitude of reasons can cause image parsing or resizing
+                # to fail. Instead of trying to catch everything, log the error
+                # and move on.
+                logger.warning(
+                    "Could not resize %s, ignoring",
+                    app.icon_path,
+                    exc_info=True
+                )
 
         appid2icon[app.appid] = final_icon_path
 

tests/test_gui.py

@@ -149,6 +149,30 @@ def test_select_game_icons_ensure_resize(
         with Image.open(resized_icon_path) as img:
             assert img.size == (32, 32)
 
+    def test_select_game_unidentifiable_icon_skipped(
+            self, gui_provider, steam_app_factory, steam_dir, home_dir, caplog):
+        """
+        Select a game using the GUI. Ensure a custom icon that's not
+        identifiable by Pillow is skipped.
+        """
+        steam_apps = [
+            steam_app_factory(name="Fake game 1", appid=10)
+        ]
+
+        icon_path = steam_dir / "appcache" / "librarycache" / "10_icon.jpg"
+        icon_path.write_bytes(b"")
+
+        gui_provider.mock_stdout = "Fake game 1: 10"
+        selected_app = select_steam_app_with_gui(
+            steam_apps=steam_apps, steam_path=steam_dir
+        )
+
+        # Warning about icon was logged, but the app was selected successfully
+        record = caplog.records[-1]
+        assert record.message.startswith(f"Could not resize {icon_path}")
+
+        assert selected_app.appid == 10
+
     def test_select_game_no_choice(
             self, gui_provider, steam_app_factory, steam_dir):
         """