Add Option type packet_id() support for Publish packet builder.

src/mqtt/packet/mod.rs

@@ -38,7 +38,7 @@ pub use self::variable_byte_integer::{DecodeResult, VariableByteInteger};
 mod packet_type;
 pub use self::packet_type::{FixedHeader, PacketType};
 mod packet_id;
-pub use self::packet_id::IsPacketId;
+pub use self::packet_id::{IntoPacketId, IsPacketId};
 pub mod v3_1_1;
 pub mod v5_0;
 pub use self::enum_packet::{GenericPacket, GenericPacketDisplay, GenericPacketTrait, Packet};

src/mqtt/packet/packet_id.rs

@@ -70,3 +70,70 @@ impl IsPacketId for u32 {
         }
     }
 }
+
+/// Trait for types that can be converted into an optional packet ID
+///
+/// This trait enables the packet_id() builder method to accept both direct values
+/// (e.g., `packet_id(42)`) and optional values (e.g., `packet_id(Some(42))` or `packet_id(None)`).
+///
+/// # Examples
+///
+/// ```
+/// use mqtt_protocol_core::mqtt::packet::IntoPacketId;
+///
+/// // Direct value
+/// let id1: Option<u16> = 42u16.into_packet_id();
+/// assert_eq!(id1, Some(42));
+///
+/// // Optional value
+/// let id2: Option<u16> = Some(42u16).into_packet_id();
+/// assert_eq!(id2, Some(42));
+///
+/// // None value
+/// let id3: Option<u16> = None::<u16>.into_packet_id();
+/// assert_eq!(id3, None);
+/// ```
+pub trait IntoPacketId<T> {
+    /// Convert self into an optional packet ID
+    fn into_packet_id(self) -> Option<T>;
+}
+
+// Implementations for u16
+
+/// Implementation for direct u16 packet ID values
+///
+/// Allows direct u16 values like `42u16` to be converted to `Some(42)`
+impl IntoPacketId<u16> for u16 {
+    fn into_packet_id(self) -> Option<u16> {
+        Some(self)
+    }
+}
+
+/// Implementation for optional u16 packet ID values
+///
+/// Allows optional values like `Some(42u16)` or `None::<u16>` to be passed through
+impl IntoPacketId<u16> for Option<u16> {
+    fn into_packet_id(self) -> Option<u16> {
+        self
+    }
+}
+
+// Implementations for u32
+
+/// Implementation for direct u32 packet ID values
+///
+/// Allows direct u32 values like `42u32` to be converted to `Some(42)`
+impl IntoPacketId<u32> for u32 {
+    fn into_packet_id(self) -> Option<u32> {
+        Some(self)
+    }
+}
+
+/// Implementation for optional u32 packet ID values
+///
+/// Allows optional values like `Some(42u32)` or `None::<u32>` to be passed through
+impl IntoPacketId<u32> for Option<u32> {
+    fn into_packet_id(self) -> Option<u32> {
+        self
+    }
+}

src/mqtt/packet/v3_1_1/publish.rs

@@ -39,7 +39,7 @@ use crate::mqtt::packet::qos::Qos;
 use crate::mqtt::packet::variable_byte_integer::VariableByteInteger;
 use crate::mqtt::packet::GenericPacketDisplay;
 use crate::mqtt::packet::GenericPacketTrait;
-use crate::mqtt::packet::IsPacketId;
+use crate::mqtt::packet::{IntoPacketId, IsPacketId};
 use crate::mqtt::result_code::MqttError;
 use crate::mqtt::{Arc, ArcPayload, IntoPayload};
 
@@ -843,9 +843,14 @@ where
     /// and must be a non-zero value. It is used to match the packet with its
     /// corresponding acknowledgment packets (PUBACK, PUBREC, etc.).
     ///
+    /// This method accepts both direct values and `Option<PacketIdType>`:
+    /// - `packet_id(42)` - Sets packet ID to 42 (for QoS 1/2, backward compatible)
+    /// - `packet_id(Some(42))` - Sets packet ID to 42 (for QoS 1/2)
+    /// - `packet_id(None)` - No packet ID (for QoS 0)
+    ///
     /// # Parameters
     ///
-    /// * `id` - The packet identifier (must be non-zero for QoS > 0)
+    /// * `id` - The packet identifier value or Option (must be non-zero for QoS > 0)
     ///
     /// # Returns
     ///
@@ -857,14 +862,32 @@ where
     /// use mqtt_protocol_core::mqtt;
     /// use mqtt_protocol_core::mqtt::packet::qos::Qos;
     ///
+    /// // Direct value (backward compatible)
     /// let builder = mqtt::packet::v3_1_1::Publish::builder()
     ///     .topic_name("test/topic")
     ///     .unwrap()
     ///     .qos(Qos::AtLeastOnce)
     ///     .packet_id(123);
+    ///
+    /// // Explicit Some
+    /// let builder = mqtt::packet::v3_1_1::Publish::builder()
+    ///     .topic_name("test/topic")
+    ///     .unwrap()
+    ///     .qos(Qos::AtLeastOnce)
+    ///     .packet_id(Some(123));
+    ///
+    /// // Explicit None for QoS 0
+    /// let builder = mqtt::packet::v3_1_1::Publish::builder()
+    ///     .topic_name("test/topic")
+    ///     .unwrap()
+    ///     .qos(Qos::AtMostOnce)
+    ///     .packet_id(None);
     /// ```
-    pub fn packet_id(mut self, id: PacketIdType) -> Self {
-        self.packet_id_buf = Some(Some(id.to_buffer()));
+    pub fn packet_id<T>(mut self, id: T) -> Self
+    where
+        T: IntoPacketId<PacketIdType>,
+    {
+        self.packet_id_buf = Some(id.into_packet_id().map(|i| i.to_buffer()));
         self
     }
 

src/mqtt/packet/v5_0/publish.rs

@@ -42,9 +42,9 @@ use crate::mqtt::packet::topic_alias_send::TopicAliasType;
 use crate::mqtt::packet::variable_byte_integer::VariableByteInteger;
 use crate::mqtt::packet::GenericPacketDisplay;
 use crate::mqtt::packet::GenericPacketTrait;
-use crate::mqtt::packet::IsPacketId;
 #[cfg(feature = "std")]
 use crate::mqtt::packet::PropertiesToBuffers;
+use crate::mqtt::packet::{IntoPacketId, IsPacketId};
 use crate::mqtt::packet::{Properties, PropertiesParse, PropertiesSize, Property};
 use crate::mqtt::result_code::MqttError;
 use crate::mqtt::{Arc, ArcPayload, IntoPayload};
@@ -1141,9 +1141,14 @@ where
     /// to match acknowledgment packets (PUBACK, PUBREC, etc.) with the original
     /// PUBLISH packet.
     ///
+    /// This method accepts both direct values and `Option<PacketIdType>`:
+    /// - `packet_id(42)` - Sets packet ID to 42 (for QoS 1/2, backward compatible)
+    /// - `packet_id(Some(42))` - Sets packet ID to 42 (for QoS 1/2)
+    /// - `packet_id(None)` - No packet ID (for QoS 0)
+    ///
     /// # Parameters
     ///
-    /// - `id`: The packet identifier (must be non-zero for QoS > 0)
+    /// - `id`: The packet identifier value or Option (must be non-zero for QoS > 0)
     ///
     /// # Returns
     ///
@@ -1154,11 +1159,23 @@ where
     /// ```ignore
     /// use mqtt_protocol_core::mqtt;
     ///
+    /// // Direct value (backward compatible)
     /// let builder = mqtt::packet::v5_0::Publish::builder()
     ///     .packet_id(42);
+    ///
+    /// // Explicit Some
+    /// let builder = mqtt::packet::v5_0::Publish::builder()
+    ///     .packet_id(Some(42));
+    ///
+    /// // Explicit None for QoS 0
+    /// let builder = mqtt::packet::v5_0::Publish::builder()
+    ///     .packet_id(None);
     /// ```
-    pub fn packet_id(mut self, id: PacketIdType) -> Self {
-        self.packet_id_buf = Some(Some(id.to_buffer()));
+    pub fn packet_id<T>(mut self, id: T) -> Self
+    where
+        T: IntoPacketId<PacketIdType>,
+    {
+        self.packet_id_buf = Some(id.into_packet_id().map(|i| i.to_buffer()));
         self
     }
 

tests/packet-v3_1_1-publish.rs

@@ -668,3 +668,95 @@ fn test_packet_type() {
     let packet_type = mqtt::packet::v3_1_1::Publish::packet_type();
     assert_eq!(packet_type, mqtt::packet::PacketType::Publish);
 }
+
+// Tests for packet_id() with Option interface
+
+#[test]
+fn test_qos1_with_some_packet_id_success() {
+    common::init_tracing();
+    let result = mqtt::packet::v3_1_1::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtLeastOnce)
+        .packet_id(Some(42u16))
+        .build()
+        .unwrap();
+    assert_eq!(result.packet_id(), Some(42u16));
+}
+
+#[test]
+fn test_qos2_with_some_packet_id_success() {
+    common::init_tracing();
+    let result = mqtt::packet::v3_1_1::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::ExactlyOnce)
+        .packet_id(Some(123u16))
+        .build()
+        .unwrap();
+    assert_eq!(result.packet_id(), Some(123u16));
+}
+
+#[test]
+fn test_qos1_with_none_packet_id_error() {
+    common::init_tracing();
+    let err = mqtt::packet::v3_1_1::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtLeastOnce)
+        .packet_id(None::<u16>)
+        .build()
+        .unwrap_err();
+    assert_eq!(err, mqtt::result_code::MqttError::MalformedPacket);
+}
+
+#[test]
+fn test_qos2_with_none_packet_id_error() {
+    common::init_tracing();
+    let err = mqtt::packet::v3_1_1::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::ExactlyOnce)
+        .packet_id(None::<u16>)
+        .build()
+        .unwrap_err();
+    assert_eq!(err, mqtt::result_code::MqttError::MalformedPacket);
+}
+
+#[test]
+fn test_qos0_with_none_packet_id_success() {
+    common::init_tracing();
+    let result = mqtt::packet::v3_1_1::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtMostOnce)
+        .packet_id(None::<u16>)
+        .build()
+        .unwrap();
+    assert_eq!(result.packet_id(), None);
+}
+
+#[test]
+fn test_qos0_with_some_packet_id_error() {
+    common::init_tracing();
+    let err = mqtt::packet::v3_1_1::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtMostOnce)
+        .packet_id(Some(42u16))
+        .build()
+        .unwrap_err();
+    assert_eq!(err, mqtt::result_code::MqttError::MalformedPacket);
+}
+
+#[test]
+fn test_qos0_without_packet_id_success() {
+    common::init_tracing();
+    let result = mqtt::packet::v3_1_1::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtMostOnce)
+        .build()
+        .unwrap();
+    assert_eq!(result.packet_id(), None);
+}

tests/packet-v5_0-publish.rs

@@ -1504,3 +1504,95 @@ fn test_packet_type() {
     let packet_type = mqtt::packet::v5_0::Publish::packet_type();
     assert_eq!(packet_type, mqtt::packet::PacketType::Publish);
 }
+
+// Tests for packet_id() with Option interface
+
+#[test]
+fn test_qos1_with_some_packet_id_success() {
+    common::init_tracing();
+    let result = mqtt::packet::v5_0::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtLeastOnce)
+        .packet_id(Some(42u16))
+        .build()
+        .unwrap();
+    assert_eq!(result.packet_id(), Some(42u16));
+}
+
+#[test]
+fn test_qos2_with_some_packet_id_success() {
+    common::init_tracing();
+    let result = mqtt::packet::v5_0::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::ExactlyOnce)
+        .packet_id(Some(123u16))
+        .build()
+        .unwrap();
+    assert_eq!(result.packet_id(), Some(123u16));
+}
+
+#[test]
+fn test_qos1_with_none_packet_id_error() {
+    common::init_tracing();
+    let err = mqtt::packet::v5_0::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtLeastOnce)
+        .packet_id(None::<u16>)
+        .build()
+        .unwrap_err();
+    assert_eq!(err, mqtt::result_code::MqttError::MalformedPacket);
+}
+
+#[test]
+fn test_qos2_with_none_packet_id_error() {
+    common::init_tracing();
+    let err = mqtt::packet::v5_0::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::ExactlyOnce)
+        .packet_id(None::<u16>)
+        .build()
+        .unwrap_err();
+    assert_eq!(err, mqtt::result_code::MqttError::MalformedPacket);
+}
+
+#[test]
+fn test_qos0_with_none_packet_id_success() {
+    common::init_tracing();
+    let result = mqtt::packet::v5_0::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtMostOnce)
+        .packet_id(None::<u16>)
+        .build()
+        .unwrap();
+    assert_eq!(result.packet_id(), None);
+}
+
+#[test]
+fn test_qos0_with_some_packet_id_error() {
+    common::init_tracing();
+    let err = mqtt::packet::v5_0::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtMostOnce)
+        .packet_id(Some(42u16))
+        .build()
+        .unwrap_err();
+    assert_eq!(err, mqtt::result_code::MqttError::MalformedPacket);
+}
+
+#[test]
+fn test_qos0_without_packet_id_success() {
+    common::init_tracing();
+    let result = mqtt::packet::v5_0::Publish::builder()
+        .topic_name("test/topic")
+        .unwrap()
+        .qos(mqtt::packet::Qos::AtMostOnce)
+        .build()
+        .unwrap();
+    assert_eq!(result.packet_id(), None);
+}