🛡️ RuboCop::Lts::Ruby

if ci_badges.map(&:color).detect { it != "green"} ☝️ let me know on Discord or RubyForum, as I may have missed the notification.

if ci_badges.map(&:color).all? { it == "green"} 👇️ send money so I can do more of this. FLOSS maintenance is now my full-time job.

👣 How will this project approach the September 2025 hostile takeover of RubyGems? 🚑️

I've summarized my thoughts in [this blog post](https://dev.to/galtzo/hostile-takeover-of-rubygems-my-thoughts-5hlo).

🌻 Synopsis

rubocop-lts-ruby provides a RuboCop plugin with compatibility cops for Ruby core and standard-library APIs. It reports calls to catalogued methods that are unavailable in the configured target Ruby version, helping projects catch accidental use of newer APIs before they reach supported runtimes.

💡 Info you can shake a stick at

Tokens to Remember
Works with JRuby
Works with Truffle Ruby
Works with MRI Ruby 4
Works with MRI Ruby 3
Support & Community
Source
Documentation
Compliance
Style
Maintainer 🎖️
`...` 💖	🧊 🐙 🛖 🧪

Compatibility

Compatible with MRI Ruby 3.2.0+, JRuby, and TruffleRuby. CI workflows and Appraisals are generated for MRI Ruby 3.2.0+. This test floor is configured by ruby.test_minimum in .kettle-jem.yml and may be higher than the gem's runtime compatibility floor when legacy Rubies are not practical for the current toolchain.

The amazing test matrix is powered by the kettle-dev stack.

How kettle-dev manages complexity in tests

| Gem | Source | Role | Total downloads | |-----|--------|------|---------------------| | [appraisal2](https://clickgems.clickhouse.com/dashboard/appraisal2) | [GitHub](https://github.com/appraisal-rb/appraisal2) | multi-dependency Appraisal matrix generation | [![Total downloads for appraisal2](https://img.shields.io/gem/dt/appraisal2.svg?style=flat-square)](https://clickgems.clickhouse.com/dashboard/appraisal2) | | [appraisal2-rubocop](https://clickgems.clickhouse.com/dashboard/appraisal2-rubocop) | [GitHub](https://github.com/appraisal-rb/appraisal2-rubocop) | RuboCop Appraisal generator integration | [![Total downloads for appraisal2-rubocop](https://img.shields.io/gem/dt/appraisal2-rubocop.svg?style=flat-square)](https://clickgems.clickhouse.com/dashboard/appraisal2-rubocop) | | [kettle-dev](https://clickgems.clickhouse.com/dashboard/kettle-dev) | [GitHub](https://github.com/kettle-dev/kettle-dev) | development, release, and CI workflow tooling | [![Total downloads for kettle-dev](https://img.shields.io/gem/dt/kettle-dev.svg?style=flat-square)](https://clickgems.clickhouse.com/dashboard/kettle-dev) | | [kettle-jem](https://clickgems.clickhouse.com/dashboard/kettle-jem) | [GitHub](https://github.com/kettle-dev/kettle-jem) | Appraisals & CI workflow templates | [![Total downloads for kettle-jem](https://img.shields.io/gem/dt/kettle-jem.svg?style=flat-square)](https://clickgems.clickhouse.com/dashboard/kettle-jem) | | [kettle-soup-cover](https://clickgems.clickhouse.com/dashboard/kettle-soup-cover) | [GitHub](https://github.com/kettle-dev/kettle-soup-cover) | SimpleCov coverage policy and reporting | [![Total downloads for kettle-soup-cover](https://img.shields.io/gem/dt/kettle-soup-cover.svg?style=flat-square)](https://clickgems.clickhouse.com/dashboard/kettle-soup-cover) | | [kettle-test](https://clickgems.clickhouse.com/dashboard/kettle-test) | [GitHub](https://github.com/kettle-dev/kettle-test) | standard test runner and coverage harness | [![Total downloads for kettle-test](https://img.shields.io/gem/dt/kettle-test.svg?style=flat-square)](https://clickgems.clickhouse.com/dashboard/kettle-test) | | [rubocop-lts](https://clickgems.clickhouse.com/dashboard/rubocop-lts) | [GitHub](https://github.com/rubocop-lts/rubocop-lts) | Ruby-version-aware linting | [![Total downloads for rubocop-lts](https://img.shields.io/gem/dt/rubocop-lts.svg?style=flat-square)](https://clickgems.clickhouse.com/dashboard/rubocop-lts) | | [turbo_tests2](https://clickgems.clickhouse.com/dashboard/turbo_tests2) | [GitHub](https://github.com/galtzo-floss/turbo_tests2) | parallel test execution | [![Total downloads for turbo_tests2](https://img.shields.io/gem/dt/turbo_tests2.svg?style=flat-square)](https://clickgems.clickhouse.com/dashboard/turbo_tests2) |

Federated DVCS

Find this repo on federated forges (Coming soon!)

| Federated [DVCS][💎d-in-dvcs] Repository | Status | Issues | PRs | Wiki | CI | |-------------------------------------------------|-------------------------------------------|-------------------|------------------|-----------------|----------------| | 🧪 [rubocop-lts/rubocop-lts-ruby on GitLab][📜src-gl] | The Truth | [💚][🤝gl-issues] | [💚][🤝gl-pulls] | [💚][📜gl-wiki] | 🐭 Tiny Matrix | | 🧊 [rubocop-lts/rubocop-lts-ruby on CodeBerg][📜src-cb] | An Ethical Mirror ([Donate][🤝cb-donate]) | [💚][🤝cb-issues] | [💚][🤝cb-pulls] | ➖ | ⭕️ No Matrix | | 🐙 [rubocop-lts/rubocop-lts-ruby on GitHub][📜src-gh] | Another Mirror | [💚][🤝gh-issues] | [💚][🤝gh-pulls] | [💚][📜gh-wiki] | 💯 Full Matrix |

Enterprise Support

Available as part of the Tidelift Subscription.

Need enterprise-level guarantees?

The maintainers of this and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source packages you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact packages you use. [![Get help from me on Tidelift][🏙️entsup-tidelift-img]][🏙️entsup-tidelift] - 💡Subscribe for support guarantees covering _all_ your FLOSS dependencies - 💡Tidelift is part of [Sonar][🏙️entsup-tidelift-sonar] - 💡Tidelift pays maintainers to maintain the software you depend on!
📊`@`Pointy Haired Boss: An [enterprise support][🏙️entsup-tidelift] subscription is "[never gonna let you down][🧮kloc]", and *supports* open source maintainers Alternatively: - [![Ruby Users Forum][✉️ruby-forum-img]][✉️ruby-forum] - [![Live Chat on Discord][✉️discord-invite-img-ftb]][✉️discord-invite] - [![Get help from me on Upwork][👨🏼‍🏫expsup-upwork-img]][👨🏼‍🏫expsup-upwork] - [![Get help from me on Codementor][👨🏼‍🏫expsup-codementor-img]][👨🏼‍🏫expsup-codementor]

✨ Installation

Install the gem and add to the application's Gemfile by executing:

bundle add rubocop-lts-ruby

If bundler is not being used to manage dependencies, install the gem by executing:

gem install rubocop-lts-ruby

⚙️ Configuration

The Lint/LtsRuby/UnavailableMethod cop is enabled by the plugin. It reports explicit receiver calls for catalogued APIs that were introduced after the target Ruby version. Since static analysis cannot prove the runtime type of every receiver, a project can document a known-safe exception narrowly:

Lint/LtsRuby/UnavailableMethod:
  AllowedMethods:
    - Enumerable#filter_map

The catalog is deliberately explicit. New entries should include the owning core or standard-library class and the first Ruby version that provides the method, with a spec covering the compatibility boundary.

This plugin does not set AllCops: TargetRubyVersion. That setting remains owned by the consuming RuboCop configuration, such as standard-rubocop-lts or a version-specific RuboCop compatibility gem. LintRoller supplies this gem's rule configuration, and the cop reads the effective target selected by RuboCop.

🔧 Basic Usage

Run RuboCop normally after enabling the plugin:

bundle exec rubocop

For a one-off check without editing .rubocop.yml:

bundle exec rubocop --plugin rubocop-lts-ruby

The plugin reports compatibility issues; it does not rewrite source code.

Field	Value
Package	rubocop-lts-ruby
Description	RuboCop cops that detect use of Ruby core and standard library APIs that are unavailable for the configured TargetRubyVersion.
Homepage	https://github.com/rubocop-lts/rubocop-lts-ruby
Source	https://github.com/rubocop-lts/rubocop-lts-ruby
License	`MIT`
Funding	https://github.com/sponsors/pboling, https://ko-fi.com/pboling, https://liberapay.com/pboling/donate, https://opencollective.com/rubocop-lts, https://thanks.dev/u/gh/pboling, https://tidelift.com/funding/github/rubygems/rubocop-lts-ruby, https://www.buymeacoffee.com/pboling

🦷 FLOSS Funding

While rubocop-lts tools are free software and will always be, the project would benefit immensely from some funding. Raising a monthly budget of... "dollars" would make the project more sustainable.

We welcome both individual and corporate sponsors! We also offer a wide array of funding channels to account for your preferences. Currently, Open Collective is our preferred funding platform.

If you're working in a company that's making significant use of rubocop-lts tools we'd appreciate it if you suggest to your company to become a rubocop-lts sponsor.

You can support the development of rubocop-lts tools via GitHub Sponsors, Liberapay, PayPal, Open Collective and Tidelift.

📍 NOTE
If doing a sponsorship in the form of donation is problematic for your company from an accounting standpoint, we'd recommend the use of Tidelift, where you can get a support-like subscription instead.

Open Collective for Individuals

Support us with a monthly donation and help us continue our activities. [Become a backer]

NOTE: kettle-readme-backers updates this list every day, automatically.

No backers yet. Be the first!

Open Collective for Organizations

Become a sponsor and get your logo on our README on GitHub with a link to your site. [Become a sponsor]

NOTE: kettle-readme-backers updates this list every day, automatically.

No sponsors yet. Be the first!

Another way to support open-source

I’m driven by a passion to foster a thriving open-source community – a space where people can tackle complex problems, no matter how small. Revitalizing libraries that have fallen into disrepair, and building new libraries focused on solving real-world challenges, are my passions. I was recently affected by layoffs, and the tech jobs market is unwelcoming. I’m reaching out here because your support would significantly aid my efforts to provide for my family, and my farm (11 🐔 chickens, 2 🐶 dogs, 3 🐰 rabbits, 8 🐈‍ cats).

If you work at a company that uses my work, please encourage them to support me as a corporate sponsor. My work on gems you use might show up in bundle fund.

I’m developing a new library, floss_funding, designed to empower open-source developers like myself to get paid for the work we do, in a sustainable way. Please give it a look.

Floss-Funding.dev: 👉️ No network calls. 👉️ No tracking. 👉️ No oversight. 👉️ Minimal crypto hashing. 💡 Easily disabled nags

🔐 Security

See SECURITY.md.

🤝 Contributing

If you need some ideas of where to help, you could work on adding more code coverage, check issues or PRs, or use the gem and think about how it could be better.

We so if you make changes, remember to update it.

See CONTRIBUTING.md for more detailed instructions.

🚀 Release Instructions

See CONTRIBUTING.md.

Code Coverage

Coverage service badges

[![Coverage Graph][🏀codecov-g]][🏀codecov] [![Coveralls Test Coverage][🏀coveralls-img]][🏀coveralls] [![QLTY Test Coverage][🏀qlty-covi]][🏀qlty-cov]

🪇 Code of Conduct

Everyone interacting with this project's codebases, issue trackers, chat rooms and mailing lists agrees to follow the .

🌈 Contributors

Made with contributors-img.

Also see GitLab Contributors: https://gitlab.com/rubocop-lts/rubocop-lts-ruby/-/graphs/main

📌 Versioning

This library follows for its public API where practical. For most applications, prefer the Pessimistic Version Constraint with two digits of precision.

For example:

spec.add_dependency("rubocop-lts-ruby", "~> 0.0")

📌 Is "Platform Support" part of the public API? More details inside.

Dropping support for a platform can be a breaking change for affected users. If a release changes supported platforms, it should be called out clearly in the changelog and versioned with that impact in mind. To get a better understanding of how SemVer is intended to work over a project's lifetime, read this article from the creator of SemVer: - ["Major Version Numbers are Not Sacred"][📌major-versions-not-sacred]

See CHANGELOG.md for a list of releases.

📄 License

The gem is available as open source under the terms of the MIT .

© Copyright

See LICENSE.md for the official copyright notice.

🤑 A request for help

Maintainers have teeth and need to pay their dentists. After getting laid off in an RIF in March, and encountering difficulty finding a new one, I began spending most of my time building open source tools. I'm hoping to be able to pay for my kids' health insurance this month, so if you value the work I am doing, I need your support. Please consider sponsoring me or the project.

To join the community or get help, use the RubyForum or Discord.

To say "thanks!" ☝️ Join the community or 👇️ send money.

💌 💌 💌

Please give the project a star ⭐ ♥.

Many parts of this project are actively managed by a kettle-jem smart template utilizing StructuredMerge.org merge contracts.

Thanks for RTFM. ☺️