fix(fan): fall back to settableMin/MaxFanSpeed when supportedFanSpeed is omitted (#201)

Fixes ZeroDivisionError in fan platform when supportedFanSpeed is missing on microwave vent fans (e.g. ME8000T).

custom_components/localthings/fan.py

@@ -89,11 +89,13 @@ class LocalThingsRangeHoodFan(LocalThingsEntity, FanEntity):
     """
 
     _enable_turn_on_off_backwards_compatibility = False
-    _attr_supported_features = (
-        FanEntityFeature.SET_SPEED
-        | FanEntityFeature.TURN_ON
-        | FanEntityFeature.TURN_OFF
-    )
+
+    @property
+    def supported_features(self) -> FanEntityFeature:
+        features = FanEntityFeature.TURN_ON | FanEntityFeature.TURN_OFF
+        if self.speed_count > 0:
+            features |= FanEntityFeature.SET_SPEED
+        return features
 
     def __init__(self, coordinator: LocalThingsCoordinator, bound) -> None:
         super().__init__(coordinator, bound)
@@ -119,7 +121,18 @@ class LocalThingsRangeHoodFan(LocalThingsEntity, FanEntity):
 
     def _all_speed_codes(self) -> list[str]:
         rep = self._rep(self._bound.href)
-        return [str(value) for value in rep.get(_SUPPORTED_FAN_SPEED_FIELD, ())]
+        supported = rep.get(_SUPPORTED_FAN_SPEED_FIELD)
+        if supported:
+            return [str(value) for value in supported]
+        min_s = rep.get(_MIN_FAN_SPEED_FIELD)
+        max_s = rep.get('x.com.samsung.da.hood.settableMaxFanSpeed')
+        if min_s is not None and max_s is not None:
+            try:
+                mn, mx = int(min_s), int(max_s)
+                return [str(i) for i in range(mn, mx + 1)]
+            except (ValueError, TypeError):
+                pass
+        return []
 
     def _active_speed_codes(self) -> list[str]:
         codes = self._all_speed_codes()

tests/test_range_hood_fan.py

@@ -224,3 +224,19 @@ async def test_microwave_vent_fan_set_percentage_zero_turns_off():
     await entity.async_set_percentage(0)
 
     assert coordinator.commands[-1][1] == ('speed', '0')
+
+
+def test_microwave_vent_fan_missing_supported_fan_speed_falls_back_to_settable_min_max():
+    """Hardware omitting supportedFanSpeed (e.g. ME8000T / issue #172) falls back
+    to building speed codes from settableMinFanSpeed ('0') and settableMaxFanSpeed ('3')."""
+    resources = _load_device('microwave_me7500d')
+    resources['/hood/fanspeed/vs/0'].pop('x.com.samsung.da.hood.supportedFanSpeed', None)
+    resources['/hood/fanspeed/vs/0']['x.com.samsung.da.hood.settableMinFanSpeed'] = '0'
+    resources['/hood/fanspeed/vs/0']['x.com.samsung.da.hood.settableMaxFanSpeed'] = '3'
+
+    entity = _microwave_entity(resources)
+    assert entity._all_speed_codes() == ['0', '1', '2', '3']
+    assert entity._active_speed_codes() == ['1', '2', '3']
+    assert entity.speed_count == 3
+    assert entity.supported_features & 1  # FanEntityFeature.SET_SPEED is present
+