Invalid gemspec -Illformed requirement ["#<YAML::Syck::DefaultKey:0xb5f9c990> 3.2.0"]

This can happen when upgrading to Rails 3.2.

Updating Rubygems should fix this issue.

gem update --system

Hope this helps.

ruby-on-rails ruby rspec gem gemspecs

I still had the errors after updating the rubygem.

Then I ran rvm gemset empty to delete the gems. This fixed it for me.

ruby-on-rails ruby rspec gem gemspecs

I had this issue, but all the methods above did not help.

So, I decided to move all the *3.2.0.spec within directory

/usr/local/ruby/lib/ruby/gems/1.9.1/specifications

into another directory, and things are solved.

Command:

sudo mv /usr/local/ruby/lib/ruby/gems/1.9.1/specifications/actionmailer-3.2.0.gemspec <another_dir>

Perform similar commands to other files:

CodeHunter