# Rubocop::Ruby20
See the intro [blog post](https://dev.to/pboling/rubocop-ruby-matrix-gems-nj)!
This gem requires no other gems. It depends on `rubocop`, but does not `require 'rubocop'`.
Awareness of `rubocop`'s lack of [SemVer][semver] adherence isn't evenly dispersed in the Ruby community.
The Rubocop team [has real reasons](https://github.com/semver/semver/issues/317)
for [not following SemVer](https://github.com/rubocop/rubocop/issues/4243), but if you've
found this project their reasons likely weigh less, in your context (e.g. running `rubocop` from command line), than
what brought you here.
The purpose of this gem is to constrain the `rubocop` dependency of a project in
a [SemVer compliant](https://semver.org/) (Semantic Versioning) way that aligns with the the desired minimum
compatible/supported Ruby version.
Adding this gem will facilitate the best practice of adding a `~> ` version constrained `rubocop` dependency, while
minimizing the risk of a rubocop minor / patch upgrade breaking the build. See the
official [compatibility matrix](https://github.com/rubocop/rubocop/blob/master/docs/modules/ROOT/pages/compatibility.adoc#support-matrix) (Rubocop documentation)
## Stable
All releases of this gem are stable releases. The first version is `1.0.0`.
## Installation
Without bundler execute:
$ gem install
Add this line to your application's Gemfile:
```ruby
gem 'rubocop-ruby2_0', '~> 1.0', require: false
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install rubocop-ruby2_0
## Usage
The following is optional. We'll discuss why you might want to do this after you see what it does.
Add to the top of your project's `.rubocop.yml` configuration file:
```yaml
inherit_gem:
rubocop-ruby2_0: rubocop.yml
```
This has the same effect as you declaring the following in your `.rubocop.yml`:
```yaml
AllCops:
# remove if already present in your `.rubocop.yml` to gain the full benefit of this gem!
TargetRubyVersion: 2.0
# The sibling gems for newer versions of Ruby support the NewCops directive as soon as Rubocop adds it.
# NewCops: enable
```
Let's talk about these settings.
## TargetRubyVersion
Allowing this gem to manage the target ruby version means you can switch to a different gem within the family when you upgrade to the next version of Ruby, and have nothing else to change. A single line in the `Gemfile`, and you are done.
## NewCops: enable
If you want to use this you'll have to upgrade to Ruby >= 2.4 and use the appropriate sibling gem, e.g. [`rubocop-ruby2_4`][2-4].
[2-4]: https://github.com/rubocop-semver/rubocop-ruby2_4
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and the created tag, and push the `.gem` file to [rubygems.org](https://rubygems.org).
## Contributing
See [CONTRIBUTING.md][contributing]
## Contributors
[]("https://github.com/rubocop-semver/rubocop-ruby2_0/graphs/contributors")
Made with [contributors-img](https://contrib.rocks).
## License
The gem is available as open source under the terms of
the [MIT License][license] [][license-ref].
See [LICENSE][license] for the official [Copyright Notice][copyright-notice-explainer].
Project Logos (rubocop-ruby3_1)
See [docs/images/logo/README.txt][project-logos]
Organization Logo (rubocop-semver)
Author: [Yusuf Evli][org-logo-author]
Source: [Unsplash][org-logo-source]
License: [Unsplash License][org-logo-license]
[project-logos]: https://github.com/rubocop-semver/rubocop-ruby3_1/blob/main/docs/images/logo/README.txt
[org-logo-author]: https://unsplash.com/@yusufevli
[org-logo-source]: https://unsplash.com/photos/yaSLNLtKRIU
[org-logo-license]: https://unsplash.com/license
### Copyright
* Copyright (c) 2022 [Peter H. Boling][peterboling] of [Rails Bling][railsbling]
[copyright-notice-explainer]: https://opensource.stackexchange.com/questions/5778/why-do-licenses-such-as-the-mit-license-specify-a-single-year
## Code of Conduct
Everyone interacting in the Rubocop::Ruby20 project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/rubocop-semver/rubocop-ruby2_0/blob/main/CODE_OF_CONDUCT.md).
## Versioning
This library aims to adhere to [Semantic Versioning 2.0.0][semver]. Violations of this scheme should be reported as
bugs. Specifically, if a minor or patch version is released that breaks backward compatibility, a new version should be
immediately released that restores compatibility. Breaking changes to the public API will only be introduced with new
major versions.
As a result of this policy, you can (and should) specify a dependency on this gem using
the [Pessimistic Version Constraint][pvc] with two digits of precision.
For example:
```ruby
spec.add_dependency "rubocop-ruby2_0", "~> 1.0"
```
[copyright-notice-explainer]: https://opensource.stackexchange.com/questions/5778/why-do-licenses-such-as-the-mit-license-specify-a-single-year
[gh_discussions]: https://github.com/rubocop-semver/rubocop-ruby2_0/discussions
[conduct]: https://github.com/rubocop-semver/rubocop-ruby2_0/blob/main/CODE_OF_CONDUCT.md
[contributing]: https://github.com/rubocop-semver/rubocop-ruby2_0/blob/main/CONTRIBUTING.md
[security]: https://github.com/rubocop-semver/rubocop-ruby2_0/blob/main/SECURITY.md
[license]: https://github.com/rubocop-semver/rubocop-ruby2_0/blob/main/LICENSE.txt
[license-ref]: https://opensource.org/licenses/MIT
[semver]: http://semver.org/
[pvc]: http://guides.rubygems.org/patterns/#pessimistic-version-constraint
[railsbling]: http://www.railsbling.com
[peterboling]: http://www.peterboling.com
[aboutme]: https://about.me/peter.boling
[angelme]: https://angel.co/peter-boling
[coderme]:http://coderwall.com/pboling
[followme-img]: https://img.shields.io/twitter/follow/galtzo.svg?style=social&label=Follow
[tweetme]: http://twitter.com/galtzo
[politicme]: https://nationalprogressiveparty.org
[documentation]: https://rubydoc.info/github/rubocop-semver/rubocop-ruby2_0/main
[source]: https://github.com/rubocop-semver/rubocop-ruby2_0/
[actions]: https://github.com/rubocop-semver/rubocop-ruby2_0/actions
[issues]: https://github.com/rubocop-semver/rubocop-ruby2_0/issues
[climate_maintainability]: https://codeclimate.com/github/rubocop-semver/rubocop-ruby2_0/maintainability
[code_triage]: https://www.codetriage.com/rubocop-semver/rubocop-ruby2_0
[blogpage]: http://www.railsbling.com/tags/rubocop-ruby2_0/
[rubygems]: https://rubygems.org/gems/rubocop-ruby2_0
[chat]: https://gitter.im/rubocop-semver/rubocop-ruby2_0?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge
[maintenancee_policy]: https://guides.rubyonrails.org/maintenance_policy.html#security-issues
[liberapay_donate]: https://liberapay.com/pboling/donate
[gh_sponsors]: https://github.com/sponsors/pboling