Handle fractional macOS horizontal scroll deltas

core/config.py

@@ -91,7 +91,7 @@
     "settings": {
         "start_minimized": True,
         "start_at_login": False,
-        "hscroll_threshold": 1,
+        "hscroll_threshold": 0.1,
         "invert_hscroll": False,  # swap horizontal scroll directions
         "invert_vscroll": False,  # swap vertical scroll directions
         "dpi": 1000,              # pointer speed / DPI setting
@@ -358,6 +358,16 @@ def _merge_defaults(cfg, defaults):
     return cfg
 
 
+
+def _is_compatible_type(value, default_val):
+    """Return True for values that are safe despite differing exact types."""
+    return (
+        isinstance(default_val, float)
+        and isinstance(value, int)
+        and not isinstance(value, bool)
+    )
+
+
 def _validate_types(cfg, defaults, path=""):
     """Reset values whose type doesn't match the defaults template."""
     for key, default_val in defaults.items():
@@ -370,6 +380,8 @@ def _validate_types(cfg, defaults, path=""):
                 print(f"[Config] Type mismatch at {path}.{key}: "
                       f"expected dict, got {type(cfg[key]).__name__}")
                 cfg[key] = json.loads(json.dumps(default_val))
+        elif _is_compatible_type(cfg[key], default_val):
+            continue
         elif not isinstance(cfg[key], type(default_val)):
             print(f"[Config] Type mismatch at {path}.{key}: "
                   f"expected {type(default_val).__name__}, "

tests/test_config.py

@@ -102,6 +102,37 @@ def test_migrate_updates_media_player_profile_apps(self):
         self.assertFalse(migrated["settings"]["start_at_login"])
         self.assertNotIn("start_with_windows", migrated["settings"])
 
+    def test_default_hscroll_threshold_supports_fractional_mac_deltas(self):
+        self.assertEqual(config.DEFAULT_CONFIG["settings"]["hscroll_threshold"], 0.1)
+
+    def test_load_config_preserves_integer_hscroll_threshold(self):
+        partial = {
+            "version": 9,
+            "active_profile": "default",
+            "profiles": {
+                "default": {
+                    "label": "Default",
+                    "apps": [],
+                    "mappings": {},
+                }
+            },
+            "settings": {
+                "hscroll_threshold": 1,
+            },
+        }
+
+        with tempfile.TemporaryDirectory() as temp_dir:
+            config_file = Path(temp_dir) / "config.json"
+            config_file.write_text(json.dumps(partial), encoding="utf-8")
+
+            with (
+                patch.object(config, "CONFIG_DIR", temp_dir),
+                patch.object(config, "CONFIG_FILE", str(config_file)),
+            ):
+                loaded = config.load_config()
+
+        self.assertEqual(loaded["settings"]["hscroll_threshold"], 1)
+
     def test_load_config_merges_missing_defaults_from_disk(self):
         partial = {
             "version": 3,

tests/test_engine.py

@@ -93,11 +93,12 @@ def run_target(self):
 
 
 class EngineHorizontalScrollTests(unittest.TestCase):
-    def _make_engine(self):
+    def _make_engine(self, hscroll_threshold=1):
         from core.engine import Engine
 
         cfg = copy.deepcopy(DEFAULT_CONFIG)
-        cfg["settings"]["hscroll_threshold"] = 1
+        if hscroll_threshold is not None:
+            cfg["settings"]["hscroll_threshold"] = hscroll_threshold
 
         with (
             patch("core.engine.MouseHook", _FakeMouseHook),
@@ -152,6 +153,19 @@ def test_hscroll_accumulates_fractional_mac_deltas(self):
 
         self.assertEqual(execute_action_mock.call_count, 1)
 
+    def test_default_hscroll_threshold_handles_m720_fractional_delta(self):
+        engine = self._make_engine(hscroll_threshold=None)
+        handler = engine._make_hscroll_handler("space_right")
+
+        with patch("core.engine.execute_action") as execute_action_mock:
+            handler(SimpleNamespace(
+                event_type=MouseEvent.HSCROLL_RIGHT,
+                raw_data=0.100006103515625,
+                timestamp=3.00,
+            ))
+
+        self.assertEqual(execute_action_mock.call_count, 1)
+
     def test_connection_callback_receives_current_state_immediately(self):
         engine = self._make_engine()
         engine.hook.device_connected = True