Force comm reconnect when comm is closed (e.g. kernel restarts, etc)

webio_jupyter_extension/webio-jupyter-labextension/labextension.ts

@@ -227,8 +227,15 @@ class WebIONotebookManager {
       if (stat === "restarting" || stat === "autorestarting" || stat === "dead") {
         // Stop attempting to handle callbacks if previous kernel is gone
         this._webIO.setSendCallback((msg: any) => {});
+
+        // Close comm to force a re-connect to the new/restarted kernel
+        this.comm!.close();
       }
     }, this);
+    this.comm.onClose = (msg: any) => {
+      // Undefine comm so that the next connect call creates a new comm
+      this.comm = undefined;
+    }
 
     this.setWebIOMetadata(kernel.id, this.comm.commId);
   }