Handle explicit Modbus NaN values (#90800)

Co-authored-by: jan iversen <jancasacondor@gmail.com>

homeassistant/components/modbus/__init__.py

@@ -82,6 +82,7 @@ from .const import (  # noqa: F401
     CONF_MIN_TEMP,
     CONF_MIN_VALUE,
     CONF_MSG_WAIT,
+    CONF_NAN_VALUE,
     CONF_PARITY,
     CONF_PRECISION,
     CONF_RETRIES,
@@ -123,6 +124,7 @@ from .modbus import ModbusHub, async_modbus_setup
 from .validators import (
     duplicate_entity_validator,
     duplicate_modbus_validator,
+    nan_validator,
     number_validator,
     scan_interval_validator,
     struct_validator,
@@ -298,6 +300,7 @@ SENSOR_SCHEMA = vol.All(
             vol.Optional(CONF_SLAVE_COUNT, default=0): cv.positive_int,
             vol.Optional(CONF_MIN_VALUE): number_validator,
             vol.Optional(CONF_MAX_VALUE): number_validator,
+            vol.Optional(CONF_NAN_VALUE): nan_validator,
             vol.Optional(CONF_ZERO_SUPPRESS): number_validator,
         }
     ),

homeassistant/components/modbus/base_platform.py

@@ -22,6 +22,7 @@ from homeassistant.const import (
     CONF_STRUCTURE,
     CONF_UNIQUE_ID,
     STATE_ON,
+    STATE_UNAVAILABLE,
 )
 from homeassistant.core import callback
 from homeassistant.helpers.dispatcher import async_dispatcher_connect
@@ -46,6 +47,7 @@ from .const import (
     CONF_LAZY_ERROR,
     CONF_MAX_VALUE,
     CONF_MIN_VALUE,
+    CONF_NAN_VALUE,
     CONF_PRECISION,
     CONF_SCALE,
     CONF_STATE_OFF,
@@ -101,6 +103,7 @@ class BasePlatform(Entity):
 
         self._min_value = get_optional_numeric_config(CONF_MIN_VALUE)
         self._max_value = get_optional_numeric_config(CONF_MAX_VALUE)
+        self._nan_value = entry.get(CONF_NAN_VALUE, None)
         self._zero_suppress = get_optional_numeric_config(CONF_ZERO_SUPPRESS)
 
     @abstractmethod
@@ -173,8 +176,10 @@ class BaseStructPlatform(BasePlatform, RestoreEntity):
             registers.reverse()
         return registers
 
-    def __process_raw_value(self, entry: float | int) -> float | int:
-        """Process value from sensor with scaling, offset, min/max etc."""
+    def __process_raw_value(self, entry: float | int | str) -> float | int | str:
+        """Process value from sensor with NaN handling, scaling, offset, min/max etc."""
+        if self._nan_value and entry in (self._nan_value, -self._nan_value):
+            return STATE_UNAVAILABLE
         val: float | int = self._scale * entry + self._offset
         if self._min_value is not None and val < self._min_value:
             return self._min_value
@@ -225,6 +230,10 @@ class BaseStructPlatform(BasePlatform, RestoreEntity):
         # the conversion only when it's absolutely necessary.
         if isinstance(val_result, int) and self._precision == 0:
             return str(val_result)
+        if isinstance(val_result, str):
+            if val_result == "nan":
+                val_result = STATE_UNAVAILABLE  # pragma: no cover
+            return val_result
         return f"{float(val_result):.{self._precision}f}"
 
 

homeassistant/components/modbus/const.py

@@ -30,6 +30,7 @@ CONF_MAX_VALUE = "max_value"
 CONF_MIN_TEMP = "min_temp"
 CONF_MIN_VALUE = "min_value"
 CONF_MSG_WAIT = "message_wait_milliseconds"
+CONF_NAN_VALUE = "nan_value"
 CONF_PARITY = "parity"
 CONF_REGISTER = "register"
 CONF_REGISTER_TYPE = "register_type"

homeassistant/components/modbus/validators.py

@@ -139,6 +139,20 @@ def number_validator(value: Any) -> int | float:
         raise vol.Invalid(f"invalid number {value}") from err
 
 
+def nan_validator(value: Any) -> int:
+    """Convert nan string to number (can be hex string or int)."""
+    if isinstance(value, int):
+        return value
+    try:
+        return int(value)
+    except (TypeError, ValueError):
+        pass
+    try:
+        return int(value, 16)
+    except (TypeError, ValueError) as err:
+        raise vol.Invalid(f"invalid number {value}") from err
+
+
 def scan_interval_validator(config: dict) -> dict:
     """Control scan_interval."""
     for hub in config:

tests/components/modbus/test_init.py

@@ -64,6 +64,7 @@ from homeassistant.components.modbus.const import (
 from homeassistant.components.modbus.validators import (
     duplicate_entity_validator,
     duplicate_modbus_validator,
+    nan_validator,
     number_validator,
     struct_validator,
 )
@@ -141,6 +142,23 @@ async def test_number_validator() -> None:
     pytest.fail("Number_validator not throwing exception")
 
 
+async def test_nan_validator() -> None:
+    """Test number validator."""
+
+    for value, value_type in (
+        (15, int),
+        ("15", int),
+        ("abcdef", int),
+        ("0xabcdef", int),
+    ):
+        assert isinstance(nan_validator(value), value_type)
+
+    with pytest.raises(vol.Invalid):
+        nan_validator("x15")
+    with pytest.raises(vol.Invalid):
+        nan_validator("not a hex string")
+
+
 @pytest.mark.parametrize(
     "do_config",
     [

tests/components/modbus/test_sensor.py

@@ -9,6 +9,7 @@ from homeassistant.components.modbus.const import (
     CONF_LAZY_ERROR,
     CONF_MAX_VALUE,
     CONF_MIN_VALUE,
+    CONF_NAN_VALUE,
     CONF_PRECISION,
     CONF_SCALE,
     CONF_SLAVE_COUNT,
@@ -558,6 +559,15 @@ async def test_config_wrong_struct_sensor(
             False,
             str(int(0x02010404)),
         ),
+        (
+            {
+                CONF_DATA_TYPE: DataType.INT32,
+                CONF_NAN_VALUE: "0x80000000",
+            },
+            [0x8000, 0x0000],
+            False,
+            STATE_UNAVAILABLE,
+        ),
         (
             {
                 CONF_DATA_TYPE: DataType.INT32,