Bundler could not find compatible versions for gem

问题:

I've added a gem 'koala' to my Gemfile and seems to have thrown gem versions out of whack when I run the 'bundle install' command:

Bundler could not find compatible versions for gem "faraday":
In snapshot (Gemfile.lock):
faraday (0.6.1)

In Gemfile:
koala (~> 1.2.0beta1) depends on
  faraday (~> 0.7.4)

Running `bundle update` will rebuild your snapshot from scratch, using only
the gems in your Gemfile, which may resolve the conflict.

How can I resolve this conflict?

回答1:

Delete the contents of Gemfile.lock, and run bundle install again. That's been working for me.

回答2:

Did you run bundle update as the error message points out? bundle install handles changes to the Gemfile and bundle update upgrades gems that are already managed by Bundler. The Gemfile.lock file locks in version numbers, bundle update will update any of those that aren't directly specified in your Gemfile (like gem 'rails', '3.0.9').

Deleting the Gemfile.lock will work, but running bundle update is better.

回答3:

You can't simply delete you Gemfile.lock if that is a solution then why Gemfile.lock is exist in the first place, you code depend on the versions locked in this file, try to only update the Gem which cause the conflict by using bundle update gem_name and you have to check the ReadMe if any changes needed to work with the new version otherwise you are breaking your code or others code.

回答4:

I found that by removing the specified version of rails solved the problem for me .... instead of:

gem rails, '4.0.4'

I did

gem rails

followed by deleting the Gemfile.lock and re-running bundle install

回答5:

If deleting Gemfile.lock doesn't work there is another possibility:

It may be possible a gem you are depending on has inadvertently included its own Gemfile.lock in its .gem file. The solution is to update the offending gems to not include a Gemfile.lock, rebuild and reinstall.

回答6:

An alternative is to go to your Gemfile.lock and delete all references to the offending gem (in this case the faraday gem). Then run bundle install and it'll update the Gemfile.lock to have compatible versions of the gem where it needs. If you want to be extra safe you can go to the Gemfile and specify the versions of the gems you want before doing this.

This was the only way I was able to get bundle install running for one of the systems that I'm maintaining. This system has a lot of old gems in its dependencies (58 gems at the time of writing) and so bundler has a hard time coping with it. If I delete the Gemfile.lock and run bundle install it'll blow up with multiple Bundler could not find compatible versions for gem xxxxxx errors. If I run bundle update it would also blow up with multiple Bundler could not find compatible versions for gem xxxxxx errors.