Restart kernel initial implementation (#18835)

* Restart kernel initial implementation

* Update notebook extension TestKernel

* PR comments

src/sql/workbench/contrib/notebook/browser/notebook.contribution.ts

@@ -239,6 +239,24 @@ CommandsRegistry.registerCommand({
 	}
 });
 
+CommandsRegistry.registerCommand({
+	id: 'notebook.restartKernel',
+	handler: async (accessor: ServicesAccessor) => {
+		const editorService: IEditorService = accessor.get(IEditorService);
+		if (editorService.activeEditor instanceof NotebookInput) {
+			await editorService.activeEditor.notebookModel?.clientSession?.restart();
+		}
+	}
+});
+
+MenuRegistry.appendMenuItem(MenuId.CommandPalette, {
+	command: {
+		id: 'notebook.restartKernel',
+		title: localize('restartNotebookKernel', "Restart Notebook Kernel"),
+	},
+	when: ContextKeyExpr.and(ActiveEditorContext.isEqualTo(NotebookEditor.ID))
+});
+
 MenuRegistry.appendMenuItem(MenuId.CommandPalette, {
 	command: {
 		id: TOGGLE_TAB_FOCUS_COMMAND_ID,

src/sql/workbench/contrib/notebook/test/emptySessionClasses.ts

@@ -168,6 +168,10 @@ class EmptyKernel implements nb.IKernel {
 	interrupt(): Thenable<void> {
 		return Promise.resolve(undefined);
 	}
+
+	restart(): Thenable<void> {
+		return Promise.resolve(undefined);
+	}
 }
 
 export class EmptyFuture implements FutureInternal {

src/sql/workbench/contrib/notebook/test/stubs.ts

@@ -353,7 +353,7 @@ export class ClientSessionStub implements IClientSession {
 	selectKernel(): Promise<void> {
 		throw new Error('Method not implemented.');
 	}
-	restart(): Promise<boolean> {
+	restart(): Promise<void> {
 		throw new Error('Method not implemented.');
 	}
 	setPath(path: string): Promise<void> {
@@ -464,6 +464,9 @@ export class KernelStub implements nb.IKernel {
 	interrupt(): Thenable<void> {
 		throw new Error('Method not implemented.');
 	}
+	restart(): Thenable<void> {
+		throw new Error('Method not implemented.');
+	}
 }
 
 export class FutureStub implements nb.IFuture {