Install jupyter instead of installing kernel spec (#10080)

* Install jupyter instead of installing kernel spec
For #10071

Author: DonJayamanne

news/2 Fixes/10071.md

@@ -0,0 +1 @@
+Re-install `Jupyter` instead of installing `kernelspec` if `kernelspec` cannot be found in the python environment.

src/client/datascience/jupyter/interpreter/jupyterInterpreterDependencyService.ts

@@ -57,9 +57,8 @@ function sortProductsInOrderForInstallation(products: Product[]) {
  * @returns {string}
  */
 export function getMessageForLibrariesNotInstalled(products: Product[], interpreterName?: string): string {
+    // Even though kernelspec cannot be installed, display it so user knows what is missing.
     const names = products
-        // Ignore kernelspec as it not something that can be installed.
-        .filter(product => product !== Product.kernelspec)
         .map(product => ProductNames.get(product))
         .filter(name => !!name)
         .map(name => name as string);
@@ -131,15 +130,15 @@ export class JupyterInterpreterDependencyService {
         _error?: JupyterInstallError,
         token?: CancellationToken
     ): Promise<JupyterInterpreterDependencyResponse> {
-        const productsToInstall = await this.getDependenciesNotInstalled(interpreter, token);
+        const missingProducts = await this.getDependenciesNotInstalled(interpreter, token);
         if (Cancellation.isCanceled(token)) {
             return JupyterInterpreterDependencyResponse.cancel;
         }
-        if (productsToInstall.length === 0) {
+        if (missingProducts.length === 0) {
             return JupyterInterpreterDependencyResponse.ok;
         }
 
-        const message = getMessageForLibrariesNotInstalled(productsToInstall, interpreter.displayName);
+        const message = getMessageForLibrariesNotInstalled(missingProducts, interpreter.displayName);
 
         sendTelemetryEvent(Telemetry.JupyterNotInstalledErrorShown);
         const selection = await this.applicationShell.showErrorMessage(
@@ -155,8 +154,15 @@ export class JupyterInterpreterDependencyService {
 
         switch (selection) {
             case DataScience.jupyterInstall(): {
+                // Ignore kernelspec as it not something that can be installed.
+                // If kernelspec isn't available, then re-install `Jupyter`.
+                if (missingProducts.includes(Product.kernelspec) && !missingProducts.includes(Product.jupyter)) {
+                    missingProducts.push(Product.jupyter);
+                }
+                const productsToInstall = missingProducts.filter(product => product !== Product.kernelspec);
                 // Install jupyter, then notebook, then others in that order.
                 sortProductsInOrderForInstallation(productsToInstall);
+
                 let productToInstall = productsToInstall.shift();
                 const cancellatonPromise = createPromiseFromCancellation({
                     cancelAction: 'resolve',

src/test/datascience/jupyter/interpreter/jupyterInterpreterDependencyService.unit.test.ts

@@ -84,6 +84,33 @@ suite('Data Science - Jupyter Interpreter Configuration', () => {
     test('Prompt to install if notebook is not installed', async () => testPromptIfModuleNotInstalled(true, false));
     test('Prompt to install if jupyter & notebook is not installed', async () =>
         testPromptIfModuleNotInstalled(false, false));
+    test('Reinstall Jupyter if jupyter and notebook are installed but kernelspec is not found', async () => {
+        when(installer.isInstalled(Product.jupyter, pythonInterpreter)).thenResolve(true);
+        when(installer.isInstalled(Product.notebook, pythonInterpreter)).thenResolve(true);
+        when(appShell.showErrorMessage(anything(), anything(), anything(), anything())).thenResolve(
+            // tslint:disable-next-line: no-any
+            DataScience.jupyterInstall() as any
+        );
+        when(pythonExecService.execModule('jupyter', deepEqual(['kernelspec', '--version']), anything())).thenReject(
+            new Error('Not found')
+        );
+        when(installer.install(anything(), anything(), anything())).thenResolve(InstallerResponse.Installed);
+
+        const response = await configuration.installMissingDependencies(pythonInterpreter);
+
+        // Jupyter must be installed & not kernelspec or anything else.
+        verify(installer.install(Product.jupyter, anything(), anything())).once();
+        verify(installer.install(anything(), anything(), anything())).once();
+        verify(
+            appShell.showErrorMessage(
+                anything(),
+                DataScience.jupyterInstall(),
+                DataScience.selectDifferentJupyterInterpreter(),
+                anything()
+            )
+        ).once();
+        assert.equal(response, JupyterInterpreterDependencyResponse.cancel);
+    });
 
     async function testInstallationOfJupyter(
         installerResponse: InstallerResponse,