Ruby : how to bundle install some new gems without updating existing ones

Question

I'm working on a legacy Rails app. and need to install a few new gems. We are setup to use the bundle tool. However I've been warned that we cannot do a simple bundle install as any updates to existing gems will put the system into an invalid state.

So how do I use bundle to add some new gems without touching any of the existing ones?

Answer 1

If you do bundle install, Bundler only concerns itself with new gems or new versions that you explicitly specify in your Gemfile. It'll also remove any gems from Gemfile.lock that you remove from your Gemfile.

If you do bundle update, then you end up with the problem that you describe in your question. It'll update existing gems, especially if no specific version is specified for each gem.

Here is a more in-depth explanation: http://viget.com/extend/bundler-best-practices. There is an "INSTALL VS. UPDATE" section that you'll probably want to read.

Update

To make sure that you're in full control of your gems' versions, I recommend referencing specific versions in your Gemfile. You can do the same with Git references by indicating a specific revision.

Examples of what I've had to do recently to get sunspot_cell working in my environment, based on this post:

# The ability to do full document indexing has some "special needs" right now
gem "sunspot", git: "git://github.com/sunspot/sunspot.git", ref: "f5a6b54e8c12a500acf37cfa3b4091bc57b75db0"
gem "sunspot_solr", git: "git://github.com/sunspot/sunspot.git", ref: "f5a6b54e8c12a500acf37cfa3b4091bc57b75db0"
gem "sunspot_rails", git: "git://github.com/sunspot/sunspot.git", ref: "f5a6b54e8c12a500acf37cfa3b4091bc57b75db0", require: "sunspot_rails"
gem "sunspot_cell", git: 'git://github.com/zheileman/sunspot_cell.git', ref: "0c0b7f980b8c46bd272fe0a5a31d2c259bebe36e"
gem "sunspot_cell_jars", "0.4"
gem "progress_bar", "0.4.0"

As you can see, I want for the sunspot gem to use github.com/sunspot/sunspot, with the specific f5a6b54e8c12a500acf37cfa3b4091bc57b75db0 revision.

For the sunspot_cell_jars, I want to use version 0.4 of sunspot_cell_jars.

This keeps bundle install from messing anything up, and you stay in full control of versions.