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

I also struggled with the same failures with rvm install ruby-2.0.0 for many, MANY hours. I had tried all the different methods to install libyaml; wget source, yum and rvm. I also tried all of the different approaches listed in similar threads. Because I tried all the different methods, I had multiple installations and locations of libyaml.

RVM is perfectly capable of installing the necessary dependencies in ~/.rvm. Simply removing the libyaml files from non-RVM install fixed this issue for me:

sudo rm /usr/local/lib/libyaml*.*

rvm reinstall ruby-2.0.0-p0

Works!

Answer 2

I was having this error and noticed I had different versions of Ruby installed with HomeBrew, along with many gems that I no longer used. So did a full clean up like this:

$ brew remove --force ruby # remove all versions installed
$ sudo rm -rf /usr/local/lib/ruby # remove all gems and leftover files
$ brew install ruby
$ gem install bundler
$ bundle install

If you don't use a Gemfile, make sure you know which gems to reinstall.

Answer 3

I got this fixed finally. The issue was that even though I installed libyaml with brew, it was never linked. I had to remove a conflicting header file and then brew link libyaml.

Answer 4

for ubuntu and rvm

sudo apt-get install libtool
rvm pkg install libyaml
rvm reinstall 1.9.3

worked

Answer 5

I had the same problem (Cent OS 5.7), none of the above solutions worked to me.

// My console warning
/usr/local/rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>':
It seems your ruby installation is missing psych (for YAML output).
To eliminate this warning, please install libyaml and reinstall your ruby.

After doing several re-installs, I realized it's looking for yaml in ruby version of 1.9.1 instead of 1.9.3. So i downgraded

// obviously after installing `libyaml`
rvm remove all
rvm install 1.9.1
rvm use 1.9.1 --default

And it worked 8D!

Answer 6

I'm using

rvm 1.16.20 (version) by Wayne E. Seguin , Michal Papis [https://rvm.io/]

and also got the following error during bundle install

.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/yaml.rb:56:in `': It seems your ruby installation is missing psych (for YAML output). To eliminate this warning, please install libyaml and reinstall your ruby.

Here are three different ways to resolve this error w/o having to gem install psych

1. export LD_LIBRARY_PATH=/usr/local/lib

2. alter /etc/ld.so.conf

   sudo su - root
   echo /usr/local/lib64 >> /etc/ld.so.conf
   echo /usr/local/lib >> /etc/ld.so.conf
   ldconfig
   

3. Fix rvm ruby 1.9.3 installation via

   patch .rvm/scripts/functions/manage/ruby < ruby-1.9.3-LDFLAGS.patch
   rvm uninstall ruby-1.9.3-p194
   export LDFLAGS='-L /usr/local/lib64 -L/usr/local/lib -Xlinker -R/usr/local/lib64 -Xlinker -R/usr/local/lib'
   rvm install ruby-1.9.3-p194 --disable-binary
   grep configure_args .rvm/src/ruby-1.9.3-p194/config.log # to confirm LDFLAG
   

    $ diff  -c .rvm/{src/rvm/,}scripts/functions/manage/ruby
    *** .rvm/src/rvm/scripts/functions/manage/ruby  2012-11-10 06:28:14.000000000 +0000
    --- .rvm/scripts/functions/manage/ruby  2013-01-25 17:18:00.000000000 +0000
    ***************
    *** 106,123 ****
              # when relative is in effect libyaml is installed in ruby itself so it will be moved with ruby
              prefix_path="${rvm_rubies_path}/${rvm_ruby_string}" libyaml

    !         __rvm_update_configure_env CFLAGS="-I${rvm_rubies_path}/${rvm_ruby_string}/include"
    !         __rvm_update_configure_env LDFLAGS="-L${rvm_rubies_path}/${rvm_ruby_string}/lib"
              if [[ -d "${rvm_rubies_path}/${rvm_ruby_string}/lib64" ]]
    !         then __rvm_update_configure_env LDFLAGS="-L${rvm_rubies_path}/${rvm_ruby_string}/lib64"
              fi
            else
              libyaml_installed || libyaml # Installs libyaml

    !         __rvm_update_configure_env CFLAGS="-I${rvm_path}/usr/include"
    !         __rvm_update_configure_env LDFLAGS="-L${rvm_path}/usr/lib"
              if [[ -d "${rvm_path}/usr/lib64" ]]
    !         then __rvm_update_configure_env LDFLAGS="-L${rvm_path}/usr/lib64"
              fi
            fi

    --- 106,123 ----
              # when relative is in effect libyaml is installed in ruby itself so it will be moved with ruby
              prefix_path="${rvm_rubies_path}/${rvm_ruby_string}" libyaml

    !         __rvm_update_configure_env CFLAGS="-I${rvm_rubies_path}/${rvm_ruby_string}/include ${CFLAGS}"
    !         __rvm_update_configure_env LDFLAGS="-L${rvm_rubies_path}/${rvm_ruby_string}/lib ${LDFLAGS}"
              if [[ -d "${rvm_rubies_path}/${rvm_ruby_string}/lib64" ]]
    !         then __rvm_update_configure_env LDFLAGS="-L${rvm_rubies_path}/${rvm_ruby_string}/lib64 ${LDFLAGS}"
              fi
            else
              libyaml_installed || libyaml # Installs libyaml

    !         __rvm_update_configure_env CFLAGS="-I${rvm_path}/usr/include ${CFLAGS}"
    !         __rvm_update_configure_env LDFLAGS="-L${rvm_path}/usr/lib ${LDFLAGS}"
              if [[ -d "${rvm_path}/usr/lib64" ]]
    !         then __rvm_update_configure_env LDFLAGS="-L${rvm_path}/usr/lib64 ${LDFLAGS}"
              fi
            fi