🌲 LibraryTree

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.

I've summarized my thoughts in this blog post.

Understand where modules wander off to when they are bored, in one line of code. It is a simple, lightweight (< 100 LOC), easy-to-use tree generator. What kind of tree? A tree representation of where a module ends up being included.

module MyGemLibrary
  include LibraryTree::Watcher # <====== THERE IT IS! ONE LINE OF CODE!
end

I will find out how far back to support in Ruby versions when this runs in CI GitHub Actions.

Tokens to Remember
Works with JRuby
Works with Truffle Ruby
Works with MRI Ruby 4
Works with MRI Ruby 3
Works with MRI Ruby 2
Works with MRI Ruby 1
Support & Community
Source
Documentation
Compliance
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Maintainer 🎖️
... 💖	🧊 🐙 🛖 🧪

Compatible with MRI Ruby 1.9.2+, JRuby, and TruffleRuby. CI workflows and Appraisals are generated for MRI Ruby 2.4+. 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.

Gem	Source	Role	Total downloads
appraisal2	GitHub	multi-dependency Appraisal matrix generation
appraisal2-rubocop	GitHub	RuboCop Appraisal generator integration
kettle-dev	GitHub	development, release, and CI workflow tooling
kettle-jem	GitHub	Appraisals & CI workflow templates
kettle-soup-cover	GitHub	SimpleCov coverage policy and reporting
kettle-test	GitHub	standard test runner and coverage harness
rubocop-lts	GitHub	Ruby-version-aware linting
turbo_tests2	GitHub	parallel test execution

Support tiers describe what this project's CI actually exercises, not what may work in an untested environment:

• Parallel support: CI runs the test suite with multiple workers available.
• Unsupported: the engine/platform combination is not covered by CI and is not a project compatibility claim.

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Alternatively:

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

bundle add library_tree

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

gem install library_tree

No global configuration is required. Include LibraryTree::Watcher in the modules whose inclusion relationships should be recorded, then call LibraryTree.render when the tree is needed. Watchers may be added at any time before rendering.

Usage patterns:

1. Include Watcher into another module.

   module MyGemLibrary
     module SharedFunctionality
       include LibraryTree::Watcher
     end
   end

2. Include that other module somewhere else:

   module MyApp
     include MyGemLibrary::SharedFunctionality
   end

3. That's it! If you want to see the tree, do:

   puts LibraryTree.render

4. You're still done, but if you want more, you can watch other modules with the watcher:

   module AnotherLibrary
     include LibraryTree::Watcher
   end

5. Or you can let modules that are already watched do the watching:

   module YetAnotherLibrary
     include MyGemLibrary::SharedFunctionality
   end

6. Want to see the tree again, after those last changes?:

   puts LibraryTree.render

7. What if we go actually crazy, and do more module stuff:

   module MyApp
     include YetAnotherLibrary
   end

8. What do you expect to see? The render hasn't changed at all! The root node state of YetAnotherLibrary is already fixed, so it doesn't get made a child of MyApp. Load order matters, and this isn't a foolproof way to know all of the places a module gets used. This library is very simple and doesn't intend to be a full-fledged dependency tree, nor track dependency the way Ruby itself does.
9. Why use it?
   1. Debug infinite recursions (maybe). This library handles them, but, again, load order matters, so maybe it won't hep?
   2. It might help you understand relationships between things in your code, or library code.

Here's something almost cool. In a Rails 8.0.2 app I have this in config/applicaiton.rb:

require_relative "boot"

require "rails/all"

I patch it:

 require_relative "boot"

+require "active_support/actionable_error"
+ActiveSupport::ActionableError.send(:include, LibraryTree::Watcher)
+
 require "rails/all"

I run bin/rails c and then:

➜  bin/rails c
Loading development environment (Rails 8.0.2)
floss-funding-dev(dev)> puts LibraryTree.render
* ActiveRecord::NoDatabaseError
  * ActiveSupport::ActionableError
* ActiveRecord::PendingMigrationError
  * ActiveSupport::ActionableError
=> nil

ActiveSupport already has a DescendantsTracker module which is superceded in Ruby 3.1+ by Ruby's native Class#subclasses.

This is not that. This tracks up to the "including" parents and down to "including" children (when it does anything at all). Don't expect accurate results!

I'm not sure if this is useful to anyone, not even me, but I wanted to explore how it would work.

While galtzo-floss 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 galtzo-floss tools we'd appreciate it if you suggest to your company to become a galtzo-floss sponsor.

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

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.

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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.

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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

See SECURITY.md.

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.

See CONTRIBUTING.md.

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

Made with contributors-img.

Also see GitLab Contributors: https://gitlab.com/galtzo-floss/library_tree/-/graphs/main

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("library_tree", "~> 1.0")

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"

See CHANGELOG.md for a list of releases.

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

See LICENSE.md for the official copyright notice.

• Copyright (c) 2025-2026 Peter H. Boling

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.

💌 💌 💌

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

Thanks for RTFM. ☺️