feat(hiroz): let the examples advertise their message types

crates/hiroz/examples/demo_nodes/talker.rs

@@ -27,7 +27,10 @@ pub async fn run_talker(
 ) -> Result<()> {
     // --8<-- [start:node_setup]
     // Create a node named "talker"
-    let node = ctx.create_node("talker").build()?;
+    let node = ctx
+        .create_node("talker")
+        .with_type_description_service()
+        .build()?;
     // --8<-- [end:node_setup]
 
     // --8<-- [start:publisher_setup]

crates/hiroz/examples/laser_scan.rs

@@ -25,7 +25,10 @@ fn main() -> Result<()> {
 
 fn run_publisher() -> Result<()> {
     let ctx = ZContextBuilder::default().build()?;
-    let node = ctx.create_node("laser_scan_publisher").build()?;
+    let node = ctx
+        .create_node("laser_scan_publisher")
+        .with_type_description_service()
+        .build()?;
     let zpub = node.create_pub::<LaserScan>("scan").build()?;
 
     println!("Publishing LaserScan messages on /scan...");

crates/hiroz/examples/lifecycle/talker.rs

@@ -18,7 +18,10 @@ fn main() -> Result<()> {
     // Build a Zenoh context and create a lifecycle node.
     // The node starts in the Unconfigured state.
     let ctx = ZContextBuilder::default().build()?;
-    let mut node = ctx.create_lifecycle_node("lifecycle_talker").build()?;
+    let mut node = ctx
+        .create_lifecycle_node("lifecycle_talker")
+        .with_type_description_service()
+        .build()?;
 
     // Register callbacks for each lifecycle transition.
     // Each callback receives the previous state and must return

crates/hiroz/examples/shm_pointcloud2.rs

@@ -68,7 +68,10 @@ fn demo_user_managed_shm() -> zenoh::Result<()> {
 
     // Step 3: Create node and publisher
     let ctx = ZContextBuilder::default().build()?;
-    let node = ctx.create_node("pointcloud_publisher").build()?;
+    let node = ctx
+        .create_node("pointcloud_publisher")
+        .with_type_description_service()
+        .build()?;
     let publisher = node
         .create_pub::<PointCloud2>("cloud/user_managed")
         .build()?;
@@ -95,7 +98,10 @@ fn demo_automatic_shm() -> zenoh::Result<()> {
         .build()?;
     println!("  ✓ Context configured with automatic SHM (threshold: 10KB)");
 
-    let node = ctx.create_node("pointcloud_publisher").build()?;
+    let node = ctx
+        .create_node("pointcloud_publisher")
+        .with_type_description_service()
+        .build()?;
     let publisher = node.create_pub::<PointCloud2>("cloud/automatic").build()?;
 
     // Generate point cloud normally (using Vec<u8>)
@@ -126,7 +132,10 @@ fn demo_automatic_shm() -> zenoh::Result<()> {
 fn demo_publisher_shm_override() -> zenoh::Result<()> {
     // Context has no SHM, but publisher has its own config
     let ctx = ZContextBuilder::default().build()?;
-    let node = ctx.create_node("pointcloud_publisher").build()?;
+    let node = ctx
+        .create_node("pointcloud_publisher")
+        .with_type_description_service()
+        .build()?;
 
     // Create SHM provider for this publisher only
     let provider = Arc::new(ShmProviderBuilder::new(30 * 1024 * 1024).build()?);

crates/hiroz/examples/twist_pub.rs

@@ -5,7 +5,10 @@ use hiroz_msgs::geometry_msgs::{Twist, Vector3};
 
 fn main() -> Result<()> {
     let ctx = ZContextBuilder::default().build()?;
-    let node = ctx.create_node("twist_publisher").build()?;
+    let node = ctx
+        .create_node("twist_publisher")
+        .with_type_description_service()
+        .build()?;
     let zpub = node.create_pub::<Twist>("cmd_vel").build()?;
 
     println!("Publishing Twist messages on /cmd_vel...");

crates/hiroz/examples/z_cache/talker.rs

@@ -15,7 +15,10 @@ use hiroz::{Builder, Result, context::ZContextBuilder};
 use hiroz_msgs::std_msgs::String as RosString;
 
 pub async fn run(ctx: hiroz::context::ZContext, topic: String, count: usize) -> Result<()> {
-    let node = ctx.create_node("cache_talker").build()?;
+    let node = ctx
+        .create_node("cache_talker")
+        .with_type_description_service()
+        .build()?;
     let publisher = node.create_pub::<RosString>(&topic).build()?;
 
     println!("[talker] publishing on '{}' every 100 ms", topic);

crates/hiroz/examples/z_custom_message.rs

@@ -200,7 +200,10 @@ async fn run_status_subscriber() -> Result<()> {
 pub fn run_navigation_server(ctx: hiroz::context::ZContext) -> Result<()> {
     println!("Starting navigation service server...");
 
-    let node = ctx.create_node("navigation_server").build()?;
+    let node = ctx
+        .create_node("navigation_server")
+        .with_type_description_service()
+        .build()?;
     let mut zsrv = node.create_service::<NavigateTo>("/navigate_to").build()?;
 
     println!("Navigation server ready, waiting for requests...");

crates/hiroz/examples/z_pubsub.rs

@@ -11,7 +11,7 @@ use hiroz_msgs::std_msgs::String as RosString;
 async fn run_subscriber(ctx: ZContext, topic: String) -> Result<()> {
     // Create a ROS 2 node - the fundamental unit of computation
     // Nodes are logical groupings of publishers, subscribers, services, etc.
-    let node = ctx.create_node("Sub").build()?;
+    let node = ctx.create_node("listener").build()?;
 
     // Create a subscriber for the specified topic
     // The type parameter RosString determines what message type we'll receive
@@ -33,7 +33,10 @@ async fn run_publisher(
     payload: String,
 ) -> Result<()> {
     // Create a ROS 2 node for publishing
-    let node = ctx.create_node("Pub").build()?;
+    let node = ctx
+        .create_node("talker")
+        .with_type_description_service()
+        .build()?;
 
     // Create a publisher for the specified topic
     // The type parameter RosString determines what message type we'll send

crates/hiroz/src/context.rs

@@ -629,6 +629,7 @@ impl ZContext {
                 Some(self.namespace.clone())
             },
             enable_communication_interface: true,
+            type_description_service: false,
         }
     }
 

crates/hiroz/src/dynamic/mod.rs

@@ -77,6 +77,8 @@ pub use message::{DynamicMessage, DynamicMessageBuilder};
 #[cfg(feature = "dynamic-schema-loader")]
 pub use registry::load_schema;
 pub use registry::{SchemaRegistry, get_schema, has_schema, register_schema};
+// Exported next to `load_schema`: the two are used as a pair -- demangle a
+// graph-reported type name, then load its schema.
 pub use schema::{FieldSchema, FieldType, MessageSchema, MessageSchemaBuilder};
 pub use serdes::DynamicSerdeCdrSerdes;
 pub use serialization::SerializationFormat;
@@ -88,6 +90,7 @@ pub use type_description_service::{
     WireKeyValue, WireTypeDescription, WireTypeSource, schema_to_wire_type_description,
     wire_to_schema_type_description,
 };
+pub use type_info::ros_type_name_from_dds;
 pub use value::{DynamicValue, FromDynamic, IntoDynamic};
 
 pub(crate) use discovery::{SchemaDiscovery, discovered_schema_type_info};

crates/hiroz/src/dynamic/type_info.rs

@@ -12,7 +12,13 @@ pub(crate) fn dds_type_name_from_schema(schema: &MessageSchema) -> String {
         + "_"
 }
 
-pub(crate) fn ros_type_name_from_dds(dds_name: &str) -> String {
+/// Convert a DDS-mangled type name as it appears in liveliness tokens and the
+/// graph (`std_msgs::msg::dds_::String_`) into the canonical ROS form the schema
+/// registry and `.msg` loader expect (`std_msgs/msg/String`). Public because
+/// out-of-crate consumers (e.g. `hu`'s WASM host) resolve graph-reported types
+/// against `load_schema` and must use this exact normalisation rather than
+/// re-deriving one -- see issue #172.
+pub fn ros_type_name_from_dds(dds_name: &str) -> String {
     dds_name
         .replace("::msg::dds_::", "/msg/")
         .replace("::srv::dds_::", "/srv/")

crates/hiroz/src/lifecycle/node.rs

@@ -276,6 +276,7 @@ pub struct ZLifecycleNodeBuilder {
     pub(crate) name: String,
     pub(crate) namespace: Option<String>,
     pub enable_communication_interface: bool,
+    pub(crate) type_description_service: bool,
 }
 
 impl ZLifecycleNodeBuilder {
@@ -284,6 +285,16 @@ impl ZLifecycleNodeBuilder {
         self
     }
 
+    /// Pass-through to [`ZNodeBuilder::with_type_description_service`] on the
+    /// inner node, so publishers created via [`ZLifecycleNode::create_publisher`]
+    /// register their schemas and runtime-typed consumers can decode them.
+    ///
+    /// [`ZNodeBuilder::with_type_description_service`]: crate::node::ZNodeBuilder::with_type_description_service
+    pub fn with_type_description_service(mut self) -> Self {
+        self.type_description_service = true;
+        self
+    }
+
     pub fn disable_communication_interface(mut self) -> Self {
         self.enable_communication_interface = false;
         self
@@ -298,6 +309,9 @@ impl Builder for ZLifecycleNodeBuilder {
         if let Some(ns) = self.namespace {
             node_builder = node_builder.with_namespace(ns);
         }
+        if self.type_description_service {
+            node_builder = node_builder.with_type_description_service();
+        }
         let inner = node_builder.build()?;
 
         // Shared state machine for service closures

crates/hiroz/src/node.rs

@@ -136,6 +136,15 @@ impl ZNodeBuilder {
     /// // Static publishers also auto-register when their message type provides
     /// // MessageTypeInfo::message_schema() (e.g. generated hiroz messages).
     /// ```
+    ///
+    /// # Why this is opt-in, and why you probably want it
+    ///
+    /// ROS 2 (rclcpp/rclpy) serves the equivalent service by default, and
+    /// hiroz's own RMW layer forces it on for every node it creates. A plain
+    /// hiroz node does not: it must opt in here. Without it, runtime-typed
+    /// consumers that have no compiled knowledge of the message — `hu meter
+    /// echo`, dynamic subscribers, bridges — cannot obtain the schema and
+    /// therefore cannot decode this node's messages.
     pub fn with_type_description_service(mut self) -> Self {
         self.enable_type_desc_service = true;
         self