问题
while trying to start some old revision of an opensource rails project confronted with a cloudy error message:
"can't activate activesupport (>= 2.3.2, runtime), already activated activesupport-2.1.2"
What does it mean? Either versions of rails and activesupport are installed on my box.
I'm confused...
回答1:
Generally, a gem or plugin is loading 2.1.2 before Rails attempts to load 2.3.2. Best way to figure it out might be to comment out each gem requirement in environment.rb one at a time and see what happens.
回答2:
If you don't need the older version of the gem the easiest way to get up and running is to remove it.
gem uninstall activesupport
To remove the old versions.
回答3:
Do you have installed the recent active support gem?
回答4:
Look in the trace associated with the error message. I recently encountered this problem where there was an instance of script/process/reaper which was getting run by Capistrano and preloading the older version. In the trace it showed the file which was trying to load the older version.
回答5:
with that error, Rails' Active Support is not working, because on your machine the Active Support Gem is installed with 2.1.2 version while the project requires a recent version (2.3.2) of that gem.
IMHO, I think you have to upgrade the gem, because a lot a times I solved typing this on terminal:
gem install gem_name
where gem_name is the name of the gem you want to install. Ruby will remove the old version and install the newer. Download the activesupport-2.3.2.gem from http://rubyforge.org/frs/?group_id=570 and place it on the directory of your project and execute the command.
You can find here other gems on: http://rubygems.org/
回答6:
I was also getting the same error but later i updated the Rails and downloaded all the dependencies and issue got resolved.
来源：https://stackoverflow.com/questions/1199421/cant-activate-activesupport-2-3-2-runtime-already-activated-activesuppor