how to solve “ruby installation is missing psych” error?

Question

I used rvm to install ruby 1.9.3. even though it was successfully installed, it complained about libyaml. and now every time i wanna install a gem (say rails) this warning s

Answer 1

If you are building ruby from source (I built 1.9.3 on Fedora 20), you will need this before you do the configure/make to build ruby:

yum install libyaml-devel

(in addition to yum install libyaml.) Similar to Francis's answer using rpmforge above.

Answer 2

On Solaris:

# sudo crle -64 -l /usr/local/lib

to add /usr/local/lib to the shared library search path (see man crle)

Answer 3

In my case all I needed to do was

rm -rf /usr/local/lib/ruby/gems/2.4.0/gems/psych-2.2.4
rm -rf /usr/local/lib/ruby/gems/2.4.0/extensions/x86_64-darwin-16/2.4.0/psych-2.2.4

Now, FWIW, gem list includes

psych (2.2.4, default: 2.2.2)

Answer 4

In my case the solution was to add the psych gem to the Gemfile.

Answer 5

$ brew doctor
$ brew link libyaml

Answer 6

I built the libyaml files separately from source and installed them in /usr/local/lib. The ruby that RVM created still did not see them, and rather than muck with the makefile or the system LD_LIBRARY_PATH I just copied /usr/local/lib/libyaml* to ~/.rvm/rubies/ruby-1.9.3-p327/lib/

That quieted the warning.