Version

3.0.0-alpha.13

Reproduction link

https://github.com/maurop123/vuecli3-test

Steps to reproduce

Starting from a project generated with vue cli 3

1. npm i -D cli-plugin-foobar
2. vue invoke cli-plugin-foobar
3. open files.txt. should see files: {}

Or with pwa plugin...

1. npm i -D @vue/cli-plugin/pwa
2. vue invoke pwa
3. notice that main.js wasn't updated although it should have been

What is expected?

In postProcessFiles(files => of generator API, the files args should contain the existing files.... right?

What is actually happening?

In postProcessFiles(files => of generator API, the files args is an empty object.

I was trying to add an import statement in main.js. I noticed that the pwa plugin seems to have the same code. When I tried running it, I noticed that main.js wasn't updated.

Where pwa generator index.js checks if (main), main is probably undefined.