fix(runtime/web_worker): Don't block self.onmessage with TLA (#9619)

This commit rewrites implementation of "JsRuntime::mod_evaluate". 

Event loop is no longer polled automatically and users must manually
drive event loop forward after calling "mod_evaluate".

Co-authored-by: Nayeem Rahman <nayeemrmn99@gmail.com>
Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/runtime/web_worker.rs b/runtime/web_worker.rs
index 30869ff41..73d351c9c 100644
--- a/runtime/web_worker.rs
+++ b/runtime/web_worker.rs
@@ -325,7 +325,28 @@ impl WebWorker {
     module_specifier: &ModuleSpecifier,
   ) -> Result<(), AnyError> {
     let id = self.js_runtime.load_module(module_specifier, None).await?;
-    self.js_runtime.mod_evaluate(id).await
+
+    let mut receiver = self.js_runtime.mod_evaluate(id);
+    tokio::select! {
+      maybe_result = receiver.next() => {
+        debug!("received worker module evaluate {:#?}", maybe_result);
+        // If `None` is returned it means that runtime was destroyed before
+        // evaluation was complete. This can happen in Web Worker when `self.close()`
+        // is called at top level.
+        let result = maybe_result.unwrap_or(Ok(()));
+        return result;
+      }
+
+      event_loop_result = self.run_event_loop() => {
+        if self.has_been_terminated() {
+          return Ok(());
+        }
+        event_loop_result?;
+        let maybe_result = receiver.next().await;
+        let result = maybe_result.unwrap_or(Ok(()));
+        return result;
+      }
+    }
   }
 
   /// Returns a way to communicate with the Worker from other threads.
@@ -384,6 +405,8 @@ impl WebWorker {
       let msg = String::from_utf8(msg.to_vec()).unwrap();
       let script = format!("workerMessageRecvCallback({})", msg);
 
+      // TODO(bartlomieju): set proper script name like "deno:runtime/web_worker.js"
+      // so it's dimmed in stack trace instead of using "__anonymous__"
       if let Err(e) = self.execute(&script) {
         // If execution was terminated during message callback then
         // just ignore it