Rakefile fix for a Psych error when building the gem

[aledalgrande]

This fixes the error:

undefined method `yaml' for #<Psych::Nodes::Stream:0x007fdb74030b18>

happening when running rake gem.

Env:

• RUBYGEMS VERSION: 1.8.12
• RUBY VERSION: 1.9.2 (2011-07-09 patchlevel 290) [x86_64-darwin11.2.0]
• RVM
• bundler 1.1.rc.7

[ser1zw]

Thanks for your pull request!

But the error doesn't occur in my environment.
Could you tell me more about the error and the solution?
(ex. details of the cause of the error, why the solution fix it, full stack trace, ...)

My environments and result are:

Env 1:

• ruby 1.9.2p290 [i686-linux]
• rvm 1.10.0
• rubygems 1.8.15
• bundler 1.1.rc.7

Env 2:

• ruby 1.9.3p0 [i686-linux]
• rvm 1.10.0
• rubygems 1.8.15
• bundler 1.0.21

$ rake gem
mkdir -p pkg
mkdir -p pkg
mkdir -p pkg/opencv-0.0.6
...
cd pkg/opencv-0.0.6
mv opencv-0.0.6.gem ..
cd -

$ gem install pkg/opencv-*.gem -- --with-opencv-dir=/path/to/opencvdir
Building native extensions.  This could take a while...
Successfully installed opencv-0.0.6
1 gem installed

$ irb
1.9.2p290 :001 > require 'opencv'
 => true 
1.9.2p290 :002 > OpenCV::VERSION
 => "0.0.6" 
1.9.2p290 :003 > 

[aledalgrande]

Hi, same RVM version as you, the only difference is that I'm on a Mac (Lion).

The full error I was getting was:

$ rake gem
/Users/ale/.rvm/gems/ruby-1.9.2-p290/gems/psych-1.2.2/lib/psych.rb:93: warning: already initialized constant VERSION
/Users/ale/.rvm/gems/ruby-1.9.2-p290/gems/psych-1.2.2/lib/psych.rb:96: warning: already initialized constant LIBYAML_VERSION
cd pkg/opencv-0.0.6
rake aborted!
undefined method `yaml' for #<Psych::Nodes::Stream:0x007fdb74030b18>

Tasks: TOP => gem => pkg/opencv-0.0.6.gem

Also I noticed that the filename of the gem is not the same exact version as in the gemspec (i.e. 0.0.6.20111221003947), but couldn't report that as there is not an issue section for this project seems it has been created now.

Thanks

[ser1zw]

Hi,
I investigated the cause of the problem.
I found this problem occurs in the case that you installed Psych 1.2.2 using rubygems.

Cause of the problem

When system Psych and Psych gem exist together, they conflict with each other when executing require 'yaml'.
The following comment explains the detail:
rubygems/bundler#1541 (comment)

Psych 1.2.2 defines Psych::Nodes::Stream#yaml and uses it internally. But it is not defined in 1.2.1 or older (installed as system Psych). This causes the NoMethodError.

Solution

Your solution works well by RC version of bundler, but doesn't work well by the latest stable version (bundler 1.0.21).

I think we should adopt a different way, refering the bundler's solution:
https://github.com/carlhuda/bundler/blob/v1.1.rc.7/lib/bundler/psyched_yaml.rb

[aledalgrande]

Nice job! I did have that gem installed in fact. Will close this then.

Thanks