undefined method `reset' for RDoc::TopLevel:Class when installing a new Ruby gem

Question

For example,

$ gem install netaddr
Fetching: netaddr-1.5.1.gem (100%)
Successfully installed netaddr-1.5.1
ERROR:  While executing gem ... (NoMethodError)
    un         


        

Answer 1

When installing rdoc it tries to generate its own documentation using rdoc. The binary is installed (probably in /usr/bin), but it will not be found at the moment of gem install - if this is the first time. gem install rdoc --no-document

Answer 2

I had a similar issue:

$ gem install rdoc
Fetching: rdoc-6.0.4.gem (100%)
WARNING:  You don't have /home/myusername/.gem/ruby/2.5.0/bin in your PATH,
      gem executables will not run.
Successfully installed rdoc-6.0.4
ERROR:  While executing gem ... (NoMethodError)
    undefined method `reset' for RDoc::TopLevel:Class

Same when installing compass. After adding /home/myusername/.gem/ruby/2.5.0/bin to $PATH, this worked for me:

$ gem install rdoc
Successfully installed rdoc-6.0.4
Parsing documentation for rdoc-6.0.4
Installing ri documentation for rdoc-6.0.4
Done installing documentation for rdoc after 3 seconds
1 gem installed