[mqtt] Interpet incoming NaN as UNDEF for NumberValues (openhab#15897)

* [mqtt] Interpet incoming NaN as UNDEF for NumberValues

Since DecimalType and QuantityType don't support NaN, but
when you're linking to a topic that the device is using
floating point, NaN might happen.

---------

Signed-off-by: Cody Cutrer <cody@cutrer.us>

bundles/org.openhab.binding.mqtt.generic/src/main/java/org/openhab/binding/mqtt/generic/ChannelConfig.java

@@ -35,7 +35,9 @@ public class ChannelConfig {
 
     /**
      * If true, the channel state is not updated on a new message.
-     * Instead a postCommand() call is performed.
+     * Instead a postCommand() call is performed. If the message is
+     * not possible to send as a command (i.e. UNDEF), it will ignore
+     * this.
      */
     public boolean postCommand = false;
     public @Nullable Integer qos;

bundles/org.openhab.binding.mqtt.generic/src/main/java/org/openhab/binding/mqtt/generic/ChannelState.java

@@ -32,6 +32,7 @@
 import org.openhab.core.thing.ChannelUID;
 import org.openhab.core.types.Command;
 import org.openhab.core.types.State;
+import org.openhab.core.types.Type;
 import org.openhab.core.types.TypeParser;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -198,29 +199,34 @@ public void processMessage(String topic, byte[] payload) {
             return;
         }
 
-        Command parsedCommand;
+        Type parsedType;
         // Map the string to a command, update the cached value and post the command to the framework
         try {
-            parsedCommand = cachedValue.parseMessage(command);
+            parsedType = cachedValue.parseMessage(command);
         } catch (IllegalArgumentException | IllegalStateException e) {
             logger.warn("Command '{}' from channel '{}' not supported by type '{}': {}", strValue, channelUID,
                     cachedValue.getClass().getSimpleName(), e.getMessage());
             receivedOrTimeout();
             return;
         }
 
-        // things that are only Commands _must_ be posted as a command (like STOP)
-        if (!(parsedCommand instanceof State)) {
-            channelStateUpdateListener.postChannelCommand(channelUID, parsedCommand);
+        if (parsedType instanceof State parsedState) {
+            cachedValue.update(parsedState);
+        } else {
+            // things that are only Commands _must_ be posted as a command (like STOP)
+            channelStateUpdateListener.postChannelCommand(channelUID, (Command) parsedType);
             receivedOrTimeout();
             return;
         }
-        cachedValue.update((State) parsedCommand);
 
-        if (config.postCommand) {
-            channelStateUpdateListener.postChannelCommand(channelUID, (Command) cachedValue.getChannelState());
+        State newState = cachedValue.getChannelState();
+        // If the user explicitly wants a command sent, not an update, do that. But
+        // we have to check that the state is even possible to send as a command
+        // (i.e. not UNDEF)
+        if (config.postCommand && newState instanceof Command newCommand) {
+            channelStateUpdateListener.postChannelCommand(channelUID, newCommand);
         } else {
-            channelStateUpdateListener.updateChannelState(channelUID, cachedValue.getChannelState());
+            channelStateUpdateListener.updateChannelState(channelUID, newState);
         }
         receivedOrTimeout();
     }

bundles/org.openhab.binding.mqtt.generic/src/main/java/org/openhab/binding/mqtt/generic/values/NumberValue.java

@@ -23,10 +23,13 @@
 import org.openhab.core.library.types.DecimalType;
 import org.openhab.core.library.types.IncreaseDecreaseType;
 import org.openhab.core.library.types.QuantityType;
+import org.openhab.core.library.types.StringType;
 import org.openhab.core.library.types.UpDownType;
 import org.openhab.core.library.unit.Units;
 import org.openhab.core.types.Command;
 import org.openhab.core.types.StateDescriptionFragmentBuilder;
+import org.openhab.core.types.Type;
+import org.openhab.core.types.UnDefType;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -43,6 +46,8 @@
  */
 @NonNullByDefault
 public class NumberValue extends Value {
+    private static final String NAN = "NaN";
+
     private final Logger logger = LoggerFactory.getLogger(NumberValue.class);
     private final @Nullable BigDecimal min;
     private final @Nullable BigDecimal max;
@@ -51,7 +56,8 @@ public class NumberValue extends Value {
 
     public NumberValue(@Nullable BigDecimal min, @Nullable BigDecimal max, @Nullable BigDecimal step,
             @Nullable Unit<?> unit) {
-        super(CoreItemFactory.NUMBER, List.of(QuantityType.class, IncreaseDecreaseType.class, UpDownType.class));
+        super(CoreItemFactory.NUMBER,
+                List.of(QuantityType.class, IncreaseDecreaseType.class, UpDownType.class, StringType.class));
         this.min = min;
         this.max = max;
         this.step = step == null ? BigDecimal.ONE : step;
@@ -112,6 +118,14 @@ public Command parseCommand(Command command) throws IllegalArgumentException {
         }
     }
 
+    @Override
+    public Type parseMessage(Command command) throws IllegalArgumentException {
+        if (command instanceof StringType && command.toString().equalsIgnoreCase(NAN)) {
+            return UnDefType.UNDEF;
+        }
+        return parseCommand(command);
+    }
+
     private BigDecimal getOldValue() {
         BigDecimal val = BigDecimal.ZERO;
         if (state instanceof DecimalType decimalCommand) {

bundles/org.openhab.binding.mqtt.generic/src/main/java/org/openhab/binding/mqtt/generic/values/Value.java

@@ -27,6 +27,7 @@
 import org.openhab.core.types.CommandDescriptionBuilder;
 import org.openhab.core.types.State;
 import org.openhab.core.types.StateDescriptionFragmentBuilder;
+import org.openhab.core.types.Type;
 import org.openhab.core.types.UnDefType;
 
 /**
@@ -145,7 +146,7 @@ public void update(State newState) throws IllegalArgumentException {
      * @param command The command to parse.
      * @exception IllegalArgumentException Thrown if for example a text is assigned to a number type.
      */
-    public Command parseMessage(Command command) throws IllegalArgumentException {
+    public Type parseMessage(Command command) throws IllegalArgumentException {
         return parseCommand(command);
     }
 

bundles/org.openhab.binding.mqtt.generic/src/main/resources/OH-INF/config/number-channel-config.xml

@@ -74,7 +74,7 @@
 		<parameter name="postCommand" type="boolean">
 			<label>Is Command</label>
 			<description>If the received MQTT value should not only update the state of linked items, but command them, enable
-				this option.</description>
+				this option. Note that if the value is NaN (interpreted as UNDEF), it can only update; commands are not possible.</description>
 			<default>false</default>
 			<advanced>true</advanced>
 		</parameter>

bundles/org.openhab.binding.mqtt.generic/src/main/resources/OH-INF/i18n/mqtt.properties

@@ -109,7 +109,7 @@ thing-type.config.mqtt.number_channel.max.description = This configuration repre
 thing-type.config.mqtt.number_channel.min.label = Absolute Minimum
 thing-type.config.mqtt.number_channel.min.description = This configuration represents the minimum of the allowed range. For a percentage channel that equals zero percent.
 thing-type.config.mqtt.number_channel.postCommand.label = Is Command
-thing-type.config.mqtt.number_channel.postCommand.description = If the received MQTT value should not only update the state of linked items, but command them, enable this option.
+thing-type.config.mqtt.number_channel.postCommand.description = If the received MQTT value should not only update the state of linked items, but command them, enable this option. Note that if the value is NaN (interpreted as UNDEF), it can only update; commands are not possible.
 thing-type.config.mqtt.number_channel.qos.label = QoS
 thing-type.config.mqtt.number_channel.qos.description = MQTT QoS of this channel (0, 1, 2). Default is QoS of the broker connection.
 thing-type.config.mqtt.number_channel.qos.option.0 = At most once (best effort delivery "fire and forget")

bundles/org.openhab.binding.mqtt.generic/src/test/java/org/openhab/binding/mqtt/generic/values/ValueTests.java

@@ -37,6 +37,7 @@
 import org.openhab.core.types.Command;
 import org.openhab.core.types.State;
 import org.openhab.core.types.TypeParser;
+import org.openhab.core.types.UnDefType;
 
 /**
  * Test cases for the value classes. They should throw exceptions if the wrong command type is used
@@ -175,6 +176,9 @@ public void numberUpdate() {
         command = v.parseCommand(new QuantityType<>("20"));
         assertThat(command, is(new QuantityType<>(20, Units.WATT)));
         assertThat(v.getMQTTpublishValue(command, null), is("20"));
+
+        assertThat(v.parseMessage(new StringType("NaN")), is(UnDefType.UNDEF));
+        assertThat(v.parseMessage(new StringType("nan")), is(UnDefType.UNDEF));
     }
 
     @Test