Be more careful about sessioncontext kernelChanged and sessionChanged signal emissions

packages/apputils/src/sessioncontext.tsx

@@ -512,6 +512,8 @@ export class SessionContext implements ISessionContext {
       return;
     }
     this._isDisposed = true;
+    this._disposed.emit();
+
     if (this._session) {
       if (this.kernelPreference.shutdownOnDispose) {
         // Fire and forget the session shutdown request
@@ -531,7 +533,6 @@ export class SessionContext implements ISessionContext {
       this._busyDisposable.dispose();
       this._busyDisposable = null;
     }
-    this._disposed.emit();
     Signal.clearData(this);
   }
 
@@ -765,9 +766,11 @@ export class SessionContext implements ISessionContext {
   private _onSessionDisposed(): void {
     if (this._session) {
       this._session.dispose();
+      const oldValue = this._session;
+      this._session = null;
+      const newValue = this._session;
+      this._sessionChanged.emit({ name: 'session', oldValue, newValue });
     }
-    this._session = null;
-    this._terminated.emit(undefined);
   }
 
   /**
@@ -873,7 +876,6 @@ export class SessionContext implements ISessionContext {
   private _initializing = false;
   private _initPromise = new PromiseDelegate<boolean>();
   private _isReady = false;
-  private _terminated = new Signal<this, void>(this);
   private _kernelChanged = new Signal<
     this,
     Session.ISessionConnection.IKernelChangedArgs

packages/console-extension/src/index.ts

@@ -162,17 +162,19 @@ async function activateConsole(
   // Handle state restoration.
   void restorer.restore(tracker, {
     command: CommandIDs.create,
-    args: widget => ({
-      path: widget.content.console.sessionContext.session?.path,
-      name: widget.content.console.sessionContext.session?.name,
-      kernelPreference: {
-        name: widget.content.console.sessionContext.kernelPreference.name,
-        language:
-          widget.content.console.sessionContext.kernelPreference.language
-      }
-    }),
-    name: widget =>
-      widget.content.console.sessionContext.session?.path ?? UUID.uuid4(),
+    args: widget => {
+      const {
+        path,
+        name,
+        kernelPreference
+      } = widget.content.console.sessionContext;
+      return {
+        path,
+        name,
+        kernelPreference: { ...kernelPreference }
+      };
+    },
+    name: widget => widget.content.console.sessionContext.path ?? UUID.uuid4(),
     when: manager.ready
   });
 

packages/services/src/session/default.ts

@@ -206,8 +206,15 @@ export class SessionConnection implements Session.ISessionConnection {
     }
     this._isDisposed = true;
     this._disposed.emit();
-    this._kernel?.dispose();
-    this._kernel = null;
+
+    if (this._kernel) {
+      this._kernel.dispose();
+      let oldValue = this._kernel;
+      this._kernel = null;
+      let newValue = this._kernel;
+      this._kernelChanged.emit({ name: 'kernel', oldValue, newValue });
+    }
+
     Signal.clearData(this);
   }