refactor: remove Iron distro support (EOL)

Remove all references to ROS 2 Iron (End of Life):
- Remove iron feature flags from all Cargo.toml files
- Remove Config::iron() method and iron priority logic
- Update build.rs to use kilted instead of iron in common paths
- Update documentation to remove iron examples
- Update distro priority order: humble > kilted > rolling > jazzy

Iron reached EOL and is no longer maintained.

Author: YuanYuYuan

book/src/chapters/building.md

@@ -156,7 +156,7 @@ The build system automatically locates ROS message definitions:
 **Search order:**
 
 1. System ROS installation (`AMENT_PREFIX_PATH`, `CMAKE_PREFIX_PATH`)
-2. Common ROS paths (`/opt/ros/{rolling,jazzy,iron,humble}`)
+2. Common ROS paths (`/opt/ros/{rolling,jazzy,kilted,humble}`)
 3. Bundled assets (built-in message definitions in ros-z-codegen)
 
 This fallback mechanism enables builds without ROS 2 installed.

book/src/chapters/distro_compatibility.md

@@ -87,15 +87,12 @@ cargo nextest run --no-default-features --features humble
 
 ### Using Other Distributions
 
-For Rolling, Iron, or Kilted, simply specify the distro feature:
+For Rolling or Kilted, simply specify the distro feature:
 
 ```bash
 # Build for Rolling
 cargo build --features rolling
 
-# Build for Iron
-cargo build --features iron
-
 # Build for Kilted
 cargo build --features kilted
 ```

book/src/chapters/feature_flags.md

@@ -78,16 +78,12 @@ cargo build --no-default-features --features humble
 
 **Important:** Humble requires `--no-default-features` to avoid conflicts with the jazzy default.
 
-### `rolling` and `iron`
+### `rolling`
 
-Target newer distributions:
+Target Rolling distribution:
 
 ```bash
-# Rolling
 cargo build --features rolling
-
-# Iron
-cargo build --features iron
 ```
 
 **See also:** [ROS 2 Distribution Compatibility](./distro_compatibility.md) for detailed documentation.

book/src/chapters/message_generation.md

@@ -189,7 +189,7 @@ flowchart LR
 ```
 
 1. **System ROS:** `$AMENT_PREFIX_PATH`, `$CMAKE_PREFIX_PATH`
-2. **Standard paths:** `/opt/ros/{rolling,jazzy,iron,humble}`
+2. **Standard paths:** `/opt/ros/{rolling,jazzy,kilted,humble}`
 3. **Bundled assets:** Built-in message definitions in ros-z-codegen
 
 This fallback enables development without ROS 2 installation.

crates/ros-z-msgs/Cargo.toml

@@ -73,7 +73,6 @@ protobuf = ["prost", "ros-z/protobuf", "ros-z-codegen/protobuf"]
 humble = ["ros-z/humble"]
 jazzy = ["ros-z/jazzy"]
 rolling = ["ros-z/rolling"]
-iron = ["ros-z/iron"]
 kilted = ["ros-z/kilted"]
 python_registry = [
   "pyo3",

crates/ros-z-msgs/build.rs

@@ -316,7 +316,7 @@ fn discover_system_packages(packages: &[&str]) -> Result<Vec<PathBuf>> {
         let common_install_paths = vec![
             "/opt/ros/rolling",
             "/opt/ros/jazzy",
-            "/opt/ros/iron",
+            "/opt/ros/kilted",
             "/opt/ros/humble",
         ];
 

crates/ros-z-tests/Cargo.toml

@@ -41,5 +41,4 @@ ros2dds-interop = ["ros-msgs", "ros-z/ros2dds", "ros-z/rmw-zenoh"]
 humble = ["ros-z/humble", "ros-z-msgs/humble"]
 jazzy = ["ros-z/jazzy", "ros-z-msgs/jazzy"]
 rolling = ["ros-z/rolling", "ros-z-msgs/rolling"]
-iron = ["ros-z/iron", "ros-z-msgs/iron"]
 kilted = ["ros-z/kilted", "ros-z-msgs/kilted"]

crates/ros-z/Cargo.toml

@@ -74,11 +74,10 @@ ros2dds = ["ros-z-protocol/ros2dds"]
 # Default is jazzy (recommended for new projects)
 # For humble, use: --no-default-features --features humble,...
 # Note: Distro features are mutually exclusive - enabling multiple may cause conflicts
-humble = ["no-type-hash", "no-jazzy", "no-rolling", "no-iron", "no-kilted"]
-jazzy = ["type-hash", "no-humble", "no-rolling", "no-iron", "no-kilted"]
-rolling = ["type-hash", "no-humble", "no-jazzy", "no-iron", "no-kilted"]
-iron = ["type-hash", "no-humble", "no-jazzy", "no-rolling", "no-kilted"]
-kilted = ["type-hash", "no-humble", "no-jazzy", "no-rolling", "no-iron"]
+humble = ["no-type-hash", "no-jazzy", "no-rolling", "no-kilted"]
+jazzy = ["type-hash", "no-humble", "no-rolling", "no-kilted"]
+rolling = ["type-hash", "no-humble", "no-jazzy", "no-kilted"]
+kilted = ["type-hash", "no-humble", "no-jazzy", "no-rolling"]
 
 # Internal features for distro compatibility
 humble-compat = []
@@ -89,7 +88,6 @@ no-type-hash = ["ros-z-protocol/no-type-hash"]
 no-humble = []
 no-jazzy = []
 no-rolling = []
-no-iron = []
 no-kilted = []
 
 

crates/ros-z/examples/protobuf_demo/Cargo.toml

@@ -32,4 +32,3 @@ prost-build = { workspace = true }
 humble = ["ros-z/humble", "ros-z-msgs/humble"]
 jazzy = ["ros-z/jazzy", "ros-z-msgs/jazzy"]
 rolling = ["ros-z/rolling", "ros-z-msgs/rolling"]
-iron = ["ros-z/iron", "ros-z-msgs/iron"]

crates/ros-z/src/config.rs

@@ -61,16 +61,6 @@ impl DistroDefaults {
         }
     }
 
-    /// ROS 2 Iron defaults
-    ///
-    /// - Iron uses rmw_zenoh v0.2.x
-    /// - Real type hashes (RIHS01 format)
-    pub const fn iron() -> Self {
-        Self {
-            supports_type_hash: true,
-        }
-    }
-
     /// ROS 2 Rolling defaults
     ///
     /// - Rolling uses rmw_zenoh v0.2.x
@@ -93,16 +83,16 @@ impl DistroDefaults {
 
     /// Get the default for the currently compiled distro based on feature flags
     /// When multiple distro features are enabled (e.g., with --all-features),
-    /// priority order is: humble > iron > rolling > jazzy (default)
+    /// priority order is: humble > kilted > rolling > jazzy (default)
     pub const fn current() -> Self {
         // Priority 1: Humble
         if cfg!(feature = "humble") {
             return Self::humble();
         }
 
-        // Priority 2: Iron
-        if cfg!(feature = "iron") {
-            return Self::iron();
+        // Priority 2: Kilted
+        if cfg!(feature = "kilted") {
+            return Self::kilted();
         }
 
         // Priority 3: Rolling