build(linux): allow macOS and Windows test builds of the desktop app (#108004)

The desktop companion crate was Linux-only. All platform-specific code
lives in canvas.rs (WebKitGTK, cairo, unix sockets, SO_PEERCRED), so:
move webkit2gtk/cairo-rs/libc under linux target dependencies, gate the
canvas module, its protocol registration, invoke handler, and exit
shutdown to Linux, add a USERPROFILE home fallback and an explicit
no-op installer error for Windows, and add the multi-size icon.ico
Windows resource. Linux behavior is unchanged; macOS/Windows builds are
for testing (macOS cargo build+test green locally; Windows aarch64-msvc
built and launched in a Windows 11 ARM VM).

apps/linux/README.md

@@ -50,6 +50,7 @@ magick 32x32.png -background none -gravity center -extent 32x32 PNG32:32x32.png
 rsvg-convert -w 128 -h 128 icon-tile.svg -o 128x128.png
 rsvg-convert -w 256 -h 256 icon-tile.svg -o 128x128@2x.png
 rsvg-convert -w 512 -h 512 icon-tile.svg -o icon.png
+magick icon.png -define icon:auto-resize=256,128,64,48,32,16 icon.ico
 ```
 
 ## Packaging

apps/linux/src-tauri/Cargo.toml

@@ -14,10 +14,12 @@ tauri-build = "2.6.3"
 
 [dependencies]
 base64 = "0.22.1"
-cairo-rs = { version = "0.18.5", features = ["png"] }
 image = { version = "0.25.10", default-features = false, features = ["jpeg", "png"] }
-libc = "0.2.186"
 serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.150"
 tauri = { version = "2.11.5", features = ["image-png", "tray-icon"] }
+
+[target.'cfg(target_os = "linux")'.dependencies]
+cairo-rs = { version = "0.18.5", features = ["png"] }
+libc = "0.2.186"
 webkit2gtk = "2.0.2"

apps/linux/src-tauri/build.rs

@@ -1,4 +1,6 @@
 fn main() {
+    // Command metadata generates capability permissions independently of the
+    // target's invoke handler, so keep the Linux-only command permission known.
     const COMMANDS: &[&str] = &[
         "bootstrap",
         "canvas_a2ui_action",

apps/linux/src-tauri/src/cli.rs

@@ -122,8 +122,12 @@ impl OpenClawCli {
 }
 
 pub fn openclaw_home() -> Result<PathBuf, CliError> {
+    #[cfg(target_os = "windows")]
     let home = env::var_os("HOME")
         .filter(|value| !value.is_empty())
-        .ok_or_else(|| CliError::Environment("HOME is not set".to_string()))?;
+        .or_else(|| env::var_os("USERPROFILE").filter(|value| !value.is_empty()));
+    #[cfg(not(target_os = "windows"))]
+    let home = env::var_os("HOME").filter(|value| !value.is_empty());
+    let home = home.ok_or_else(|| CliError::Environment("HOME is not set".to_string()))?;
     Ok(PathBuf::from(home).join(".openclaw"))
 }

apps/linux/src-tauri/src/installer.rs

@@ -1,14 +1,27 @@
+#[cfg(not(target_os = "windows"))]
 use crate::cli::openclaw_home;
-use serde::{Deserialize, Serialize};
+use serde::Deserialize;
+#[cfg(not(target_os = "windows"))]
+use serde::Serialize;
+#[cfg(not(target_os = "windows"))]
 use std::collections::VecDeque;
+#[cfg(not(target_os = "windows"))]
 use std::io::{BufRead, BufReader};
+#[cfg(not(target_os = "windows"))]
 use std::process::{Command, Stdio};
+#[cfg(not(target_os = "windows"))]
 use std::sync::mpsc;
+#[cfg(not(target_os = "windows"))]
 use std::thread;
+#[cfg(not(target_os = "windows"))]
 use tauri::path::BaseDirectory;
-use tauri::{AppHandle, Emitter, Manager};
+use tauri::AppHandle;
+#[cfg(not(target_os = "windows"))]
+use tauri::{Emitter, Manager};
 
+#[cfg(not(target_os = "windows"))]
 const INSTALL_EVENT: &str = "install-progress";
+#[cfg(not(target_os = "windows"))]
 const ERROR_TAIL_LINES: usize = 24;
 
 #[derive(Clone, Copy, Debug, Deserialize)]
@@ -20,6 +33,7 @@ pub enum InstallChannel {
 }
 
 impl InstallChannel {
+    #[cfg(not(target_os = "windows"))]
     fn version(self) -> &'static str {
         match self {
             Self::Stable => "latest",
@@ -29,6 +43,7 @@ impl InstallChannel {
     }
 }
 
+#[cfg(not(target_os = "windows"))]
 #[derive(Clone, Serialize)]
 #[serde(rename_all = "camelCase")]
 struct InstallProgress<'a> {
@@ -36,6 +51,12 @@ struct InstallProgress<'a> {
     line: &'a str,
 }
 
+#[cfg(target_os = "windows")]
+pub fn install(_app: &AppHandle, _channel: InstallChannel) -> Result<(), String> {
+    Err("CLI installation is unavailable in this Windows test build.".to_string())
+}
+
+#[cfg(not(target_os = "windows"))]
 pub fn install(app: &AppHandle, channel: InstallChannel) -> Result<(), String> {
     let script = app
         .path()
@@ -107,6 +128,7 @@ pub fn install(app: &AppHandle, channel: InstallChannel) -> Result<(), String> {
     }
 }
 
+#[cfg(not(target_os = "windows"))]
 fn stream_lines<R>(
     stream: &'static str,
     reader: R,

apps/linux/src-tauri/src/main.rs

@@ -1,3 +1,4 @@
+#[cfg(target_os = "linux")]
 mod canvas;
 mod cli;
 mod gateway;
@@ -280,28 +281,41 @@ async fn gateway_action(
 }
 
 fn main() {
-    let app = canvas::register_protocol(tauri::Builder::default())
-        .setup(|app| {
-            let window = app
-                .get_webview_window("main")
-                .expect("tauri.conf.json must define the main window");
-            let state = DesktopState::new(window.url()?);
-            app.manage(state.clone());
-            match canvas::CanvasBridge::start(app.handle().clone()) {
-                Ok(bridge) => {
-                    app.manage(bridge);
-                }
-                Err(error) => eprintln!("Canvas bridge unavailable: {error}"),
+    let builder = tauri::Builder::default();
+    #[cfg(target_os = "linux")]
+    let builder = canvas::register_protocol(builder);
+
+    let builder = builder.setup(|app| {
+        let window = app
+            .get_webview_window("main")
+            .expect("tauri.conf.json must define the main window");
+        let state = DesktopState::new(window.url()?);
+        app.manage(state.clone());
+        #[cfg(target_os = "linux")]
+        match canvas::CanvasBridge::start(app.handle().clone()) {
+            Ok(bridge) => {
+                app.manage(bridge);
             }
-            state.set_tray(tray::build(app, state.clone())?);
-            Ok(())
-        })
-        .invoke_handler(tauri::generate_handler![
-            bootstrap,
-            canvas::canvas_a2ui_action,
-            install_cli,
-            gateway_action
-        ])
+            Err(error) => eprintln!("Canvas bridge unavailable: {error}"),
+        }
+        state.set_tray(tray::build(app, state.clone())?);
+        Ok(())
+    });
+    #[cfg(target_os = "linux")]
+    let builder = builder.invoke_handler(tauri::generate_handler![
+        bootstrap,
+        canvas::canvas_a2ui_action,
+        install_cli,
+        gateway_action
+    ]);
+    #[cfg(not(target_os = "linux"))]
+    let builder = builder.invoke_handler(tauri::generate_handler![
+        bootstrap,
+        install_cli,
+        gateway_action
+    ]);
+
+    let app = builder
         .on_window_event(|window, event| {
             if let tauri::WindowEvent::CloseRequested { api, .. } = event {
                 let state = window.app_handle().state::<DesktopState>();
@@ -314,10 +328,13 @@ fn main() {
         .build(tauri::generate_context!())
         .expect("OpenClaw desktop app failed");
     app.run(|app, event| {
+        #[cfg(target_os = "linux")]
         if matches!(event, tauri::RunEvent::Exit) {
             if let Some(bridge) = app.try_state::<canvas::CanvasBridge>() {
                 bridge.shutdown();
             }
         }
+        #[cfg(not(target_os = "linux"))]
+        let _ = (app, event);
     });
 }