Solution to invalid gem format

http://weblog.rubyonrails.org/2008/6/1/rails-2-1-time-zones-dirty-caching-gem-dependencies-caching-etc

# hrisff on 24 Jun 06:02:

Anyone else getting this?

$ sudo gem install rails ERROR: Error installing rails: invalid gem
format for /usr/local/lib/ruby/gems/1.8/cache/activesupport-2.1.0.gem

2.0.2 is installed and working. Using gem v1.2.0 on Leopard

deleting the cached gem and retrying doesn’t help.
# pentor on 24 Jun 14:45:

Same problem here as chrisff also today… could it be a bug in that
file or in the repository?
# Vincenzo Acinapura on 24 Jun 15:08:

Same problem here, I’ve installed rubygems 1.2.0 and ruby 1.8.7-p22.
When I try to install rails, I get “invalid gem format for /usr/local/
lib/ruby/gems/1.8/cache/activesupport-2.1.0.gem”
# JoeTheIntern on 24 Jun 16:12:

Exact problem as chris, pentor and Vince – it was driving me crazy.
Deleting the cache did not help – the gem magically reappears each
time.

I managed to install ActiveSupport 2.1.0 by downloading from its
rubyforge project page manually and installing locally, and then “gem
install rails” goes through just fine. Looks like a bad repository
version to me.

Was upgrading from Rails 1.2.3 on Vista, using RubyGems 1.2.
# TomH on 24 Jun 19:21:

I used @JoeTheIntern’s instructions and was able to resolve the
problem.

http://rubyforge.org/projects/activesupport/

Download gem to a local file, then

sudo gem install—local activesupport-2.1.0.gem

All fixed.

Thanks Joe!

I found that the problem was using gems.github.com as one of the
source repositories.
once i removed it, and cleaned out the cache directory, things worked
fine.