Update: move init command to separate package

designs/2020-init-command-eslint-cli/README.md

@@ -0,0 +1,119 @@
+- Repo: [eslint/eslint](https://github.com/eslint/eslint)
+- Start Date: 2020-06-29
+- RFC PR: 
+- Authors: Aniketh Saha ([anikethsaha](https://github.com/anikethsaha))
+
+# Move --init flag into a separate utility
+
+## Summary
+
+Move the `init` command from main repo ([eslint](https://github.com/eslint/eslint)) to a new repo named `@eslint/create`
+
+## Motivation
+
+Currently the whole `init` command is being shipped with the cli in the main repo. Though its not that much of size (roughly ~0.6MB for the [eslint/lib/init](https://github.com/eslint/eslint/tree/master/lib/init)), this command is not a type of command that we need everyday or everytime running eslint. It is mainly used when creating a new project or adding eslint to a project for the first time. So if we move this to a separate package that is meant to use in the command line, 
+We will make use of tools like `npx` to simply run `npx @eslint/create` or using `npm` to run `npm init @eslint` or using `yarn` to run `yarn create @eslint` single time for a project instead of having it in the core project. 
+
+## Detailed Design
+
+<!--
+   This is the bulk of the RFC.
+
+   Explain the design with enough detail that someone familiar with ESLint
+   can implement it by reading this document. Please get into specifics
+   of your approach, corner cases, and examples of how the change will be
+   used. Be sure to define any new terms in this section.
+-->
+
+The implementation is mainly migrating the code from main repo to `@eslint/create`. As far as the modules are concerned, all shared modules are being shipped currently with the eslint so we can use those modules through eslint itself. 
+
+The approach would be following these steps
+
+- Move the `eslint/lib/init/*` to the new repo's `src/*` directory
+- Add the following `dependencies` in `package.json`
+  - `enquirer`
+  - `progress`
+  - `semver`
+  - `espree` (peer)
+  - `lodash`
+  - `json-stable-stringify-without-jsonify`
+  - `cross-spawn`
+  - `eslint` (peer)
+  - `debug` (peer)
+- for all those modules coming inside `../**/*`, it would be replaced using `eslint/**/*`
+- For `tests`, move the `tests/lib/init` to new repo's `tests/init`
+- Add the following `devDependencies` in `package.json`
+  - `chai`
+  - `sinon`
+  - `js-yaml`
+  - `proxyquire`
+  - `shelljs`
+- create `tests/utils` and add the following functions 
+  - [`defineInMemoryFs`](https://github.com/eslint/eslint/blob/6677180495e16a02d150d0552e7e5d5f6b77fcc5/tests/_utils/in-memory-fs.js#L250)
+- for `conf/*`, it is not a part of the public API and it cant be accessed from `eslint` module, we need a keep these synced with the main repo (`eslint`). We can choose from the following approach to solve this : 
+  - using the `eslint-github-bot`, whenever there is a PR opened that changes the file for the `conf` directory in `eslint` repo, create an issue in the `@eslint/create` repo to have a look in the PR and if required submit a change in `@eslint/create`.
+  - OR, while doing the release for both `eslint` and `@eslint/create` repos, the release script can be configured to copy-parse the `conf` folder from `eslint` to `@eslint/create` before the release just like the `website` repo is being updated currently. 
+- After completion of this repo, whenever someone uses the `--init` flag, an error will be thrown stating the correct step to do the migration i.e using `npx @eslint/create` or `npm @eslint` or `yarn @eslint`. I am not suggesting to use run the `@eslint/create` module whenever `--init` command is being called because this would require to use the `@eslint/create` module as a dependency in `eslint` and in `@eslint/create` we are already being using `eslint` as a dependency, so there would be circular dependencies.
+
+## Documentation
+
+<!--
+    How will this RFC be documented? Does it need a formal announcement
+    on the ESLint blog to explain the motivation?
+-->
+Documentation for `@eslint/create` will be created with proper usage and each prompt's details. In the main documentation, a link to `@eslint/create` will be given [here](https://github.com/eslint/eslint/blob/master/docs/user-guide/command-line-interface.md#--init) and basic usage and the package details will be documented below as a deprecated notice and migration guide. 
+Also in the cli command options, [here](https://github.com/eslint/eslint/blob/master/docs/user-guide/command-line-interface.md#options), for `--init` we need to change the description for this with deprecated details as the command is still active just that there will be error that will recommend to use `@eslint/create` package instead.
+Yes as it will be a major change for the `eslint` repo itself as it is being removed from the main package/repo, I guess a blog can be a good solution to solve initial queries. 
+
+## Drawbacks
+
+<!--
+    Why should we *not* do this? Consider why adding this into ESLint
+    might not benefit the project or the community. Attempt to think 
+    about any opposing viewpoints that reviewers might bring up. 
+
+    Any change has potential downsides, including increased maintenance
+    burden, incompatibility with other tools, breaking existing user
+    experience, etc. Try to identify as many potential problems with
+    implementing this RFC as possible.
+-->
+- This might increase the maintenance burden as this will add one more repo in the organization. 
+- We may need to face challenges like re-directing of issues from `@eslint/create` repo to `eslint` and vice-versa. 
+- If we do not add proper tooling for handling the `conf` directory in `eslint` to `@eslint/create` repo as mentioned in the [detailed design](@detailed_design)'s 7th point, there will be an overhead work on looking through each PR/change particularly to find out whether there is a need for updating the `conf` directory in `@eslint/create` or not. 
+
+
+## Backwards Compatibility Analysis
+
+<!--
+    How does this change affect existing ESLint users? Will any behavior
+    change for them? If so, how are you going to minimize the disruption
+    to existing users?
+-->
+- Releasing with a proper message which the command is being run from `eslint` with something like - `"this command has been moved from here, use 'npx @eslint/create'"` might be a good way to address backward compatibility. 
+- Or whenever `--init` command is being used, show a warning and run `npx @eslint/create` using `child_process` of the native node modules. 
+- Otherwise we can keep the feature in the main repo as well for starting few days/weeks with a warning and then removing it completing with an error message but this would lead to circular dependencies and that is not an ideal case for managing dependencies, so I think we should remove this feature completely with an error message as mentioned above. 
+
+## Alternatives
+
+<!--
+    What other designs did you consider? Why did you decide against those?
+
+    This section should also include prior art, such as whether similar
+    projects have already implemented a similar feature.
+-->
+The current implementation in `eslint` repo is the alternative. No changes needed. 
+
+## Open Questions
+
+<!--
+    This section is optional, but is suggested for a first draft.
+
+    What parts of this proposal are you unclear about? What do you
+    need to know before you can finalize this RFC?
+
+    List the questions that you'd like reviewers to focus on. When
+    you've received the answers and updated the design to reflect them, 
+    you can remove this section.
+-->
+
+Do we want to implement this as monorepo under `eslint` repo or a separate repo `@eslint/create` but github will make it as `eslint-create` or similar ?