[cs_themes] recover from corrupted icon cache

files/usr/share/cinnamon/cinnamon-settings/modules/cs_themes.py

@@ -15,6 +15,7 @@
 
 from pathlib import Path
 import config
+from icon_theme_cache import read_icon_cache
 
 ICON_SIZE = 48
 
@@ -718,13 +719,7 @@ def refresh_chooser(self, chooser, path_suffix, themes, callback):
             else:
                 read_path = '/usr/share/cinnamon/cinnamon-settings/icons'
 
-            icon_paths = {}
-            with open(read_path, 'r') as cache_file:
-                for line in cache_file:
-                    theme_name, icon_path = line.strip().split(':')
-                    icon_paths[theme_name] = icon_path
-
-            dump = False
+            icon_paths, dump = read_icon_cache(read_path)
 
             # Collect all themes with their categories and variants
             categorized_themes = []

files/usr/share/cinnamon/cinnamon-settings/modules/icon_theme_cache.py

@@ -0,0 +1,24 @@
+def read_icon_cache(path):
+    """Read valid theme icon entries and report whether the cache was damaged."""
+    icon_paths = {}
+    damaged = False
+
+    with open(path, "r", encoding="utf-8", errors="replace") as cache_file:
+        for line in cache_file:
+            entry = line.strip()
+            if "\ufffd" in entry or any(ord(char) < 32 or ord(char) == 127 for char in entry):
+                damaged = True
+                continue
+
+            if ":" not in entry:
+                damaged = True
+                continue
+
+            theme_name, icon_path = entry.split(":", 1)
+            if not theme_name or not icon_path:
+                damaged = True
+                continue
+
+            icon_paths[theme_name] = icon_path
+
+    return icon_paths, damaged

tests/test_icon_theme_cache.py

@@ -0,0 +1,52 @@
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+MODULES = (
+    Path(__file__).resolve().parents[1]
+    / "files/usr/share/cinnamon/cinnamon-settings/modules"
+)
+sys.path.insert(0, str(MODULES))
+
+from icon_theme_cache import read_icon_cache
+
+
+class ReadIconCacheTest(unittest.TestCase):
+    def test_skips_corrupt_lines_and_preserves_colons_in_paths(self):
+        with tempfile.TemporaryDirectory() as temp_dir:
+            cache = Path(temp_dir) / "icons"
+            cache.write_bytes(
+                b"valid:icons/valid.png\n"
+                b"missing-separator\n"
+                b"\xffinvalid:icons/invalid.png\n"
+                b"binary\x00theme:icons/binary.png\n"
+                b"colon:path:with:colons.png\n"
+                b":missing-name\n"
+                b"empty-path:\n"
+            )
+
+            icon_paths, damaged = read_icon_cache(cache)
+
+        self.assertTrue(damaged)
+        self.assertEqual(
+            icon_paths,
+            {
+                "valid": "icons/valid.png",
+                "colon": "path:with:colons.png",
+            },
+        )
+
+    def test_valid_cache_is_not_marked_damaged(self):
+        with tempfile.TemporaryDirectory() as temp_dir:
+            cache = Path(temp_dir) / "icons"
+            cache.write_text("theme:icons/folder.svg\n", encoding="utf-8")
+
+            icon_paths, damaged = read_icon_cache(cache)
+
+        self.assertFalse(damaged)
+        self.assertEqual(icon_paths, {"theme": "icons/folder.svg"})
+
+
+if __name__ == "__main__":
+    unittest.main()