gemdiff

gemdiff is a command-line utility to find and compare source code repositories associated with ruby gems. It makes it easy to compare source code differences between the current version of a gem in your bundle and the latest version of the gem.

Why?

  1. Looking up the github repository for a gem often requires The Google.
  2. Many gems do not have the source repository URL in the gemspec.
  3. You should Always Be Updating. This makes it easier.

Install

gem install gemdiff

Commands

outdated

Runs bundle outdated --strict on the project in the current directory. For each outdated gem, it prompts you if you would like to open the compare view for that gem. Enter 'y' to review or enter to skip.

This is the default task so you can just run gemdiff.

$ cd /your/ruby/project/using/bundler
$ gemdiff
Checking for outdated gems in your bundle...
aws-sdk: 1.35.0 > 1.34.1
Open? (y to open, else skip)
webmock: 1.17.4 > 1.17.3
Open? (y to open, else skip) y
sprockets: 2.11.0 > 2.10.1
Open? (y to open, else skip)

compare

You don't need to use bundler or be in a project. You can query a specific gem by entering explicit version numbers.

For example, open the GitHub compare view in browser for difference between versions 4.0.2 and 5.0.0:

$ gemdiff compare arel --new=5.0.0 --old=4.0.2

find

Lookup the repository URL using the gemspec. If a GitHub URL is not found, hit the GitHub search API.

$ gemdiff find arel
http://github.com/rails/arel

open

Open the repository URL:

$ gemdiff open arel

releases

Open the repository's release history page:

$ gemdiff releases arel

It didn't work

gemdiff operates on a few assumptions:

  1. The gem must have a repository on GitHub. If not, gemdiff will find nothing or a similar repository, which is not helpful.

  2. The GitHub repository must have tagged releases to show compare views.

  3. The versions must be tagged using the standard name format of v1.2.3. If you find exceptions that follow a non-standard pattern, please submit a pull request. See lib/gemdiff/outdated_gem.rb.

  4. Encourage gem maintainers to either enter the GitHub repository URL in the homepage field of their gemspec, or anywhere in the description. gemdiff is much faster if so, and if not, it guesses the best match using the GitHub search API.