Fix silent error, add custom panic handler

This is to work around Tokio's panic recovery feature.
Ref tokio-rs/tokio#495
Ref tokio-rs/tokio#209
Ref denoland#1311
Fixes denoland#2097

Author: ry

cli/compiler.rs

@@ -111,6 +111,13 @@ fn lazy_start(parent_state: ThreadSafeState) -> ResourceId {
 
       let mut runtime = C_RUNTIME.lock().unwrap();
       runtime.spawn(lazy(move || {
+        // Tokio swallows panics. In order to actually crash when we panic, we
+        // have to set this custom hook.
+        std::panic::set_hook(Box::new(|panic_info| {
+          eprintln!("{}", panic_info.to_string());
+          std::process::abort();
+        }));
+
         worker.then(move |result| -> Result<(), ()> {
           // Close resource so the future created by
           // handle_worker_message_stream exits

cli/tokio_util.rs

@@ -13,6 +13,12 @@ pub fn run<F>(future: F)
 where
   F: Future<Item = (), Error = ()> + Send + 'static,
 {
+  // Tokio swallows panics. In order to actually crash when we panic, we
+  // have to set this custom hook.
+  std::panic::set_hook(Box::new(|panic_info| {
+    eprintln!("{}", panic_info.to_string());
+    std::process::abort();
+  }));
   // tokio::runtime::current_thread::run(future)
   tokio::run(future)
 }
@@ -40,7 +46,15 @@ where
   let rt = tokio::runtime::Runtime::new().unwrap();
   let mut executor = rt.executor();
   let mut enter = tokio_executor::enter().expect("Multiple executors at once");
-  tokio_executor::with_default(&mut executor, &mut enter, move |_enter| f());
+  tokio_executor::with_default(&mut executor, &mut enter, move |_enter| {
+    // Tokio swallows panics. In order to actually crash when we panic, we
+    // have to set this custom hook.
+    std::panic::set_hook(Box::new(|panic_info| {
+      eprintln!("{}", panic_info.to_string());
+      std::process::abort();
+    }));
+    f()
+  });
 }
 
 #[derive(Debug)]

cli/worker.rs

@@ -324,7 +324,7 @@ mod tests {
         onmessage = function(e) {
           console.log("msg from main script", e.data);
           if (e.data == "exit") {
-            close();
+            delete window.onmessage;
             return;
           } else {
             console.assert(e.data === "hi");