feat: add platform debugging and cross-compile detection (#17)

- Add 'gitclaw platform' command to show detected OS/arch
- Add check_target_mismatch() to detect cross-compiled binaries
- Warn on startup if binary was compiled for different OS than runtime
- Prevents confusing issues like Darwin binary selecting wrong packages on Linux

Example warning:  'This gitclaw binary was compiled for macOS but is running on Linux.'

Author: clawdeeo

src/cli.rs

@@ -42,6 +42,8 @@ pub enum Commands {
         #[arg(value_enum)]
         shell: Shell,
     },
+    /// Show platform information
+    Platform {},
     /// Update gitclaw itself
     SelfUpdate {
         /// Only check for updates, don't install

src/main.rs

@@ -33,6 +33,11 @@ async fn main() {
 
     let cli = Cli::parse();
 
+    // Check for platform mismatch (e.g., Darwin binary on Linux)
+    if let Some(warning) = platform::check_target_mismatch() {
+        eprintln!("{}", warning);
+    }
+
     // Load configuration and merge with CLI args
     let config = match Config::load() {
         Ok(cfg) => cfg,
@@ -85,6 +90,21 @@ async fn run(cli: Cli, config: Config) -> anyhow::Result<()> {
             let name = cmd.get_name().to_string();
             generate(shell, &mut cmd, name, &mut std::io::stdout());
         }
+        Commands::Platform {} => {
+            let (os, arch) = gitclaw::platform::current_platform()?;
+            println!("Detected platform: {} {}", os, arch);
+            #[cfg(target_os = "macos")]
+            println!("Compiled for: macOS");
+            #[cfg(target_os = "linux")]
+            println!("Compiled for: Linux");
+            #[cfg(target_os = "windows")]
+            println!("Compiled for: Windows");
+            println!("OS aliases: {:?}", os.aliases());
+            println!("Arch aliases: {:?}", arch.aliases());
+            if let Some(warning) = gitclaw::platform::check_target_mismatch() {
+                println!("\n{}", warning);
+            }
+        }
         Commands::SelfUpdate { check } => {
             if check {
                 self_update::check_for_update(&config).await?

src/platform.rs

@@ -91,6 +91,49 @@ pub fn current_platform() -> Result<(OS, Arch), PlatformError> {
     Ok((detect_os()?, detect_arch()?))
 }
 
+/// Check if the binary's compile target matches runtime platform
+/// This catches cross-compiled binaries run under emulation
+pub fn check_target_mismatch() -> Option<String> {
+    // Use conditional compilation to detect the compiled target
+    let compiled_for_macos = cfg!(target_os = "macos");
+    let compiled_for_linux = cfg!(target_os = "linux");
+    let compiled_for_windows = cfg!(target_os = "windows");
+
+    let runtime_os = std::env::consts::OS;
+
+    // If compiled for macOS but running on Linux (e.g., under Rosetta or emulation)
+    if compiled_for_macos && runtime_os == "linux" {
+        return Some(
+            "Warning: This gitclaw binary was compiled for macOS but is running on Linux.\n\
+             This will cause incorrect package selection.\n\
+             Please install the Linux version or build from source: cargo install --path ."
+                .to_string(),
+        );
+    }
+
+    // If compiled for Linux but running on macOS
+    if compiled_for_linux && runtime_os == "macos" {
+        return Some(
+            "Warning: This gitclaw binary was compiled for Linux but is running on macOS.\n\
+             This will cause incorrect package selection.\n\
+             Please install the macOS version or build from source: cargo install --path ."
+                .to_string(),
+        );
+    }
+
+    // If compiled for Windows but running on Unix
+    if compiled_for_windows && (runtime_os == "linux" || runtime_os == "macos") {
+        return Some(
+            "Warning: This gitclaw binary was compiled for Windows but is running on a Unix system.\n\
+             This will cause incorrect package selection.\n\
+             Please install the correct version for your OS."
+                .to_string(),
+        );
+    }
+
+    None
+}
+
 pub fn score_asset(name: &str, os: OS, arch: Arch) -> i32 {
     let lower = name.to_lowercase();
     let mut score = 0;