create-app: Make new frontend system the default

The new frontend system is now the default template when creating a new
Backstage app. The previous `--next` flag has been replaced with a
`--legacy` flag that can be used to create an app using the old frontend
system instead.

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

.changeset/new-frontend-system-default.md

@@ -0,0 +1,5 @@
+---
+'@backstage/create-app': minor
+---
+
+**BREAKING**: The new frontend system is now the default template when creating a new Backstage app. The previous `--next` flag has been replaced with a `--legacy` flag that can be used to create an app using the old frontend system instead.

docs/frontend-system/building-apps/01-index.md

@@ -20,10 +20,10 @@ The create-app CLI requires Node.js Active LTS Release, see the [prerequisites d
 ```sh
 # The command bellow creates a Backstage App inside the current folder.
 # The name of the app-folder is the name that was provided when prompted.
-npx @backstage/create-app@latest --next
+npx @backstage/create-app@latest
 ```
 
-Using the `--next` flag will result in a Backstage app using the New Frontend System which will be further explained in the sections below.
+This will create a Backstage app using the new frontend system which will be further explained in the sections below.
 
 ## The app instance
 

docs/frontend-system/building-apps/08-migrating.md

@@ -899,7 +899,7 @@ It's encouraged that once you switch over to using the new frontend system, that
 
 This practice is also pretty important early on, as it's going to help you get familiar with the practices of the new frontend system.
 
-When creating a new Backstage app with `create-app` and using the `--next` flag you'll automatically get these choices in the `yarn new` command, but if you want to bring these templates to an older app, you can add the following to your root `package.json`:
+When creating a new Backstage app with `create-app` you'll automatically get these choices in the `yarn new` command, but if you want to bring these templates to an older app, you can add the following to your root `package.json`:
 
 ```json
 {

packages/create-app/cli-report.md

@@ -8,7 +8,7 @@
 Usage: backstage-create-app [options]
 
 Options:
-  --next
+  --legacy
   --path [directory]
   --skip-install
   --template-path [directory]

packages/create-app/src/createApp.test.ts

@@ -69,7 +69,7 @@ describe('command entrypoint', () => {
     expect(tryInitGitRepositoryMock).toHaveBeenCalled();
     expect(templatingMock).toHaveBeenCalled();
     expect(templatingMock.mock.lastCall?.[0]).toEqual(
-      findOwnPaths(__dirname).resolve('templates/default-app'),
+      findOwnPaths(__dirname).resolve('templates/next-app'),
     );
     expect(templatingMock.mock.lastCall?.[1]).toContain(
       path.join(tmpdir(), 'MyApp'),
@@ -85,20 +85,20 @@ describe('command entrypoint', () => {
     expect(tryInitGitRepositoryMock).toHaveBeenCalled();
     expect(templatingMock).toHaveBeenCalled();
     expect(templatingMock.mock.lastCall?.[0]).toEqual(
-      findOwnPaths(__dirname).resolve('templates/default-app'),
+      findOwnPaths(__dirname).resolve('templates/next-app'),
     );
     expect(templatingMock.mock.lastCall?.[1]).toEqual('myDirectory');
     expect(buildAppMock).toHaveBeenCalled();
   });
 
-  it('should call expected tasks when `--next` is supplied', async () => {
-    const cmd = { next: true } as unknown as Command;
+  it('should call expected tasks when `--legacy` is supplied', async () => {
+    const cmd = { legacy: true } as unknown as Command;
     await createApp(cmd);
     expect(checkAppExistsMock).toHaveBeenCalled();
     expect(tryInitGitRepositoryMock).toHaveBeenCalled();
     expect(templatingMock).toHaveBeenCalled();
     expect(templatingMock.mock.lastCall?.[0]).toEqual(
-      findOwnPaths(__dirname).resolve('templates/next-app'),
+      findOwnPaths(__dirname).resolve('templates/default-app'),
     );
     expect(templatingMock.mock.lastCall?.[1]).toContain(
       path.join(tmpdir(), 'MyApp'),

packages/create-app/src/createApp.ts

@@ -63,12 +63,12 @@ export default async (opts: OptionValues): Promise<void> => {
     },
   ]);
 
-  // Pick the built-in template based on the --next flag
+  // Pick the built-in template based on the --legacy flag
   /* eslint-disable-next-line no-restricted-syntax */
   const ownPaths = findOwnPaths(__dirname);
-  const builtInTemplate = opts.next
-    ? ownPaths.resolve('templates/next-app')
-    : ownPaths.resolve('templates/default-app');
+  const builtInTemplate = opts.legacy
+    ? ownPaths.resolve('templates/default-app')
+    : ownPaths.resolve('templates/next-app');
 
   // Use `--template-path` argument as template when specified. Otherwise, use the default template.
   const templateDir = opts.templatePath

packages/create-app/src/index.ts

@@ -31,7 +31,7 @@ const main = (argv: string[]) => {
     .name('backstage-create-app')
     .version(version)
     .description('Creates a new app in a new directory or specified path')
-    .option('--next', 'Use the next generation of the app template')
+    .option('--legacy', 'Use the legacy version of the app template')
     .option(
       '--path [directory]',
       'Location to store the app defaulting to a new folder with the app name',