gemdiff

Gem Version Build Status

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. gemdiff helps connect gem version management (rubygems + bundler) with source code (github).

Why?

You want to quickly view the source code differences between versions of gems when your dependencies are updated. It is often not that easy, because finding the github repository for a gem often requires The Google since many gems do not have the source repository URL in their gemspec.

How?

gemdiff does the repository lookup by inspecting the gemspec, then searching github if needed. It uses bundler to list your outdated gems. For each outdated gem, it determines your currently used version and the version you can update to, and builds a compare view URL with the old and new version tags. It also provides update to assist in the bundle update and commit workflow.

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outdated

Runs bundle outdated --strict on the project in the current directory. For each outdated gem, it prompts you if you would like to open the compare view for that gem.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Checking for outdated gems in your bundle...
Fetching gem metadata from https://rubygems.org/.......
Fetching additional metadata from https://rubygems.org/..
Resolving dependencies...

Outdated gems included in the bundle:
  * aws-sdk (1.35.0 > 1.34.1)
  * sprockets (2.11.0 > 2.10.1)
  * webmock (1.17.4 > 1.17.3)
aws-sdk: 1.35.0 > 1.34.1
Open? (y to open, else skip)
sprockets: 2.11.0 > 2.10.1
Open? (y to open, else skip) y
webmock: 1.17.4 > 1.17.3
Open? (y to open, else skip)

compare

You can open a compare view for an individual outdated gem in your bundle:

$ gemdiff compare haml

You can also bypass bundler and query a gem by including the old and new version numbers.

For example, open the GitHub compare view in browser for difference between haml versions 4.0.4 and 4.0.5:

$ gemdiff compare haml 4.0.4 4.0.5

update

gemdiff can simplify your git workflow around updating gems. Use update to update a gem in your bundle and commit the change to your repository. You will be shown a preview of the git diff and you may choose to commit or reset the change.

$ gemdiff update haml

Updating haml...
diff --git a/Gemfile.lock b/Gemfile.lock
index d5544ef..2d5def8 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -38,7 +38,7 @@ GEM
     dalli (2.7.0)
     debugger-linecache (1.2.0)
     erubis (2.7.0)
-    haml (4.0.4)
+    haml (4.0.5)
       tilt
     hike (1.2.3)
     i18n (0.6.9)

Commit? (c to commit, r to reset, else do nothing) c

commit ebcc13f4c9a43f2e844d9d185e527652021c6a8f
Author: Tee Parham
Date:   Mon Mar 3 16:38:32 2014 -0700

    Update haml to 4.0.5

diff --git a/Gemfile.lock

find

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

$ gemdiff find haml
http://github.com/haml/haml

open

Open the repository URL:

$ gemdiff open haml

releases

Open the repository's release history page:

$ gemdiff releases haml

commits

Open the repository's master branch commit history page:

$ gemdiff commits haml

help

$ gemdiff help

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.

  5. Some gems' source code is not on github (gasp!). gemdiff could support other source hosts. Submit a PR!