无法加载 mysql2 gem

Question

我已经看过somedifferentanswers，但这些都没有帮助我......

这就是诀窍：我必须在不接触 Gemfile 的情况下解决这个问题。我目前正在创建我的工作环境，以便它与生产服务器匹配，因此，我根本无法修改 rails 的代码。

我的操作系统：OSX 10.11

红宝石：红宝石 2.0.0p643

导轨：4.0.0

gem 是 gem 'mysql2' 的 Gemfile。执行bundle install 时没有错误，但是当我尝试rake db:migrate --trace 时，输出如下：

rake aborted!
There was an error while trying to load the gem 'mysql2'.
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:80:in `rescue in block (2 levels) in require'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `each'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:72:in `block in require'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `each'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler/runtime.rb:61:in `require'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/bundler-1.11.2/lib/bundler.rb:99:in `require'
/Users/redar/redar/config/application.rb:7:in `<top (required)>'
/Users/redar/redar/Rakefile:4:in `require'
/Users/redar/redar/Rakefile:4:in `<top (required)>'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/rake_module.rb:25:in `load'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/rake_module.rb:25:in `load_rakefile'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:637:in `raw_load_rakefile'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:94:in `block in load_rakefile'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:165:in `standard_exception_handling'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:93:in `load_rakefile'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:77:in `block in run'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:165:in `standard_exception_handling'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/lib/rake/application.rb:75:in `run'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/gems/rake-10.1.0/bin/rake:33:in `<top (required)>'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/bin/rake:23:in `load'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/bin/rake:23:in `<main>'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/bin/ruby_executable_hooks:15:in `eval'
/Users/redar/.rvm/gems/ruby-2.0.0-p643/bin/ruby_executable_hooks:15:in `<main>'

我不知道如何解释。 Rakefile 有问题吗？

另外，这是output from the mkmf.log

---

编辑：这是我的 Rakefile 的内容，位于 myapp/folder

# Add your own tasks in files placed in lib/tasks ending in .rake,
# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.

require File.expand_path('../config/application', __FILE__)

MyApp::Application.load_tasks

Answer 1

试试

bundle exec rake db:migrate

这将确保您正在执行“rake db:migrate”，并且 Gemfile 中列出的 gem 已加载且可用。如果你在没有“bundle exec”的情况下运行它，你可能只使用可用的系统 gem 来执行。