I get a pg error when trying to destroy a controller - ruby-on-rails

Question

I work on windows, have rails 3.2.12(just upgraded) and ruby 2.0.0p0. when i try to delete a controller i get this error:
F:\my apps\meshworks-redo> rails d controller Plans
C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/pg-0.14.1-x86-mingw32/lib/pg.rb:10:in `require': cannot load such file -- 2.0/pg_ext (LoadError)
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/pg-0.14.1-x86-mingw32/lib/pg.rb:10:in `rescue in <top (required)>'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/pg-0.14.1-x86-mingw32/lib/pg.rb:3:in `<top (required)>'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/bundler-1.3.2/lib/bundler/runtime.rb:72:in `require'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/bundler-1.3.2/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/bundler-1.3.2/lib/bundler/runtime.rb:70:in `each'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/bundler-1.3.2/lib/bundler/runtime.rb:70:in `block in require'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/bundler-1.3.2/lib/bundler/runtime.rb:59:in `each'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/bundler-1.3.2/lib/bundler/runtime.rb:59:in `require'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/bundler-1.3.2/lib/bundler.rb:132:in `require'
from F:/my apps/meshworks-redo/config/application.rb:7:in `<top (required)>'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/commands.rb:24:in `require'
from C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/railties-3.2.12/lib/rails/commands.rb:24:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
I tried re installing the pg gem, no luck.

Answer 1

A friend of mine got the same problem when using Ruby 2.0 on Windows 7 with Postgres. It occurs not only when trying to destroy a controller, but for every database action (including rake db:create). The problem is that the pg_ext.so file is not included for ruby 2.0. It is included for 1.9, but simply copying this to the 2.0 does not seem work. However, I found another method to obtain the correct pg_ext.so. Not exactly sure why this works, but it works for him. Here is what you need to do:
Go to the folder where 2.0/pg_ext.so (the file that could not be found) should be located. In your case C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/pg-0.14.1-x86-mingw32/lib/.
Create a folder called '2.0' (without the quotes) here.
In this folder you will need the correct pg_ext.so file. You can obtain this in the following way:
Manually install the pg gem ("gem install pg" in console). This installs the non x86-mingw32 version of the gem. It does not fix the problem, but it does create the correct pg_ext.so. I think this is because it compiles the pg gem for your system, so for ruby 2.0. You can then use this pg_ext.so file with the pg x86-mingw32 version. You will need DevKit in order to compile and install pg (http://rubyinstaller.org/add-ons/devkit/).
Go to the location of pg_ext.so in the pg-0.14.1 gem folder. In your case this would be C:/Users/rrw/.pik/rubies/Ruby-200-p0/lib/ruby/gems/2.0.0/gems/pg-0.14.1/lib.
Copy the file pg_ext.so from this folder to the newly pg-0.14.1-x86-mingw32/lib/2.0/ folder in step 2.
Now retry your commands and check if everything works. If it does not, delete your Gemfile.lock and re-run bundle install.
The same problem with this gem might occur with other mingw32 gems as well. IFor example, I had the same problem with the bcrypt-rails gem. Following the same steps as described above fixed the problem. I am now successfully running Ruby 2.0 on Windows 7.
Ps. If you have any other problems running the pg gem on Windows 7 64 bit, then try to install the 32 bit x86 version of Ruby (the RubyInstaller) and postgresql. Furthermore, make sure you include the Ruby folders in your path (this is an option while installing ruby 2.0 using the RubyInstaller) as well as the Postgresql lib and bin folders.
Good luck!