升级Ruby版本后rails new与gem install无法正常使用求助

Hey there, let’s work through those random issues you’re hitting after switching to Ruby 2.5.0 and Rails 5.1.4. I’ve dealt with plenty of environment-specific quirks when upgrading Ruby/Rails versions, especially in containerized setups like Codeanywhere. Here’s a practical breakdown of steps to diagnose and fix this:

1. Verify Your RVM Environment is Fully Switched #

Sometimes rvm use ruby-2.5.0 doesn’t stick across sessions or might leave residual references to your old Ruby version. Let’s confirm your active environment:
Run these commands in your terminal:

ruby -v
rails -v
gem env

• Double-check that ruby -v outputs ruby 2.5.0p0 (or similar) and rails -v shows Rails 5.1.4.
• In the gem env output, look for the GEM PATHS section—make sure it points to a directory under ~/.rvm/gems/ruby-2.5.0 (not your old 2.3.4 path). If it doesn’t, try running rvm use ruby-2.5.0 --default to set it as the default for future sessions.

2. Clean Up Gem Dependencies #

Ruby version upgrades can leave behind gem binaries compiled for the old Ruby, which cause unpredictable errors. Let’s refresh your gems:

• First, clean up unused gems:

  gem cleanup
  

• Navigate to your new Rails app directory and reinstall dependencies from scratch:

  bundle install --clean
  

The --clean flag ensures any old gem versions are removed, so you’re only using gems built for Ruby 2.5.0.

3. Update System Libraries for Ubuntu 14.04 #

Ubuntu 14.04 is pretty old, and Ruby 2.5.0/Rails 5.1.4 require newer system libraries than your previous setup. Specifically, OpenSSL 1.0.2+ is needed for Ruby 2.5.0. Let’s install/update the required libraries:

sudo apt-get update
sudo apt-get install libssl-dev libreadline-dev zlib1g-dev

After installing these, recompile Ruby 2.5.0 to ensure it links against the updated libraries:

rvm reinstall ruby-2.5.0 --with-openssl-dir=/usr/lib/ssl

4. Pinpoint the "Random" Issues with Logs #

Random errors often have a pattern—you just need to catch them in the act. Next time a problem occurs:

• Check your Rails development log immediately: cat log/development.log (look for the most recent error entries at the bottom).
• Save any terminal error output—even partial messages can help identify issues like permission problems, thread conflicts, or missing dependencies.
  Common culprits in containerized setups:
  • File permissions: Run ls -la in your app directory to ensure your user owns all files (Codeanywhere containers sometimes have odd permission defaults).
  • Thread conflicts: Rails 5.1 uses Puma as the default server (instead of WEBrick in Rails 4.2). Puma is multi-threaded, which can expose race conditions or compatibility issues with older system libraries. Test switching back to WEBrick temporarily:
    1. Add gem 'webrick' to your Gemfile.
    2. Run bundle install.
    3. Start the server with:

       rails s -b 0.0.0.0 -u webrick
       

If the problem stops, you can either stick with WEBrick for development or adjust Puma’s config (reduce thread count in config/puma.rb) to mitigate the issue.

5. Restart Your Codeanywhere Container #

Sometimes container environments get into a weird state—restarting the container can clear up transient glitches that don’t show up in logs. You can do this from the Codeanywhere dashboard by stopping and restarting your Ubuntu container.

Give these steps a shot, and if you can capture specific error messages, that’ll make it even easier to zero in on the exact problem.

内容的提问来源于stack exchange，提问作者S. Harper