Ruby on rails 安装rbenv时如何解决gem依赖关系？

最近我安装了rbenv，并将ruby指定为2.3.1，将rails指定为5.1.1，但我无法运行我的项目，因为我得到：

Ignoring json-2.1.0 because its extensions are not built.  Try: gem pristine json --version 2.1.0
Ignoring nokogiri-1.8.1 because its extensions are not built.  Try: gem pristine nokogiri --version 1.8.1
Ignoring unf_ext-0.0.7.4 because its extensions are not built.  Try: gem pristine unf_ext --version 0.0.7.4
Ignoring yajl-ruby-1.3.1 because its extensions are not built.  Try: gem pristine yajl-ruby --version 1.3.1
/var/lib/gems/2.3.0/gems/bundler-1.16.1/lib/bundler/spec_set.rb:88:in `block in materialize': Could not find unf_ext-0.0.7.4 in any of the sources (Bundler::GemNotFound)

from /var/lib/gems/2.3.0/gems/bundler-1.16.1/lib/bundler/spec_set.rb:82:in `map!'
...
from /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/spring-2.0.2/bin/spring:49:in `<main>'

安装成功通过，但。。。现在我得到：

bundle install

/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/ffi-1.9.18/lib/ffi.rb:6:in `require': incompatible library version - /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/ffi-1.9.18/lib/ffi_c.so (LoadError)
    from /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/ffi-1.9.18/lib/ffi.rb:6:in `rescue in <top (required)>'
    from /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/ffi-1.9.18/lib/ffi.rb:3:in `<top (required)>'
    from /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/rb-inotify-0.9.8/lib/rb-inotify/native.rb:1:in `require'
    from /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/rb-inotify-0.9.8/lib/rb-inotify/native.rb:1:in `<top (required)>'
    from /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/rb-inotify-0.9.8/lib/rb-inotify.rb:1:in `require'
    from /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/rb-inotify-0.9.8/lib/rb-inotify.rb:1:in `<top (required)>'
    from /home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/listen-3.0.8/lib
    ...
    from /home/alex/.rbenv/versions/2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    from -e:1:in `<main>'

/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/ffi-1.9.18/lib/ffi.rb:6:in'require'：不兼容的库版本-/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/ffi-1.9.18/lib/ffi_c.so（加载错误）
from/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/ffi-1.9.18/lib/ffi.rb:6:in'rescue in'
from/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/ffi-1.9.18/lib/ffi.rb:3:in`'
from/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/rb-inotify-0.9.8/lib/rb-inotify/native.rb:1:in'require'
from/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/rb-inotify-0.9.8/lib/rb-inotify/native.rb:1:in`'
from/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/rb-inotify-0.9.8/lib/rb-inotify.rb:1:in'require'
from/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/rb-inotify-0.9.8/lib/rb-inotify.rb:1:in`'
from/home/alex/pnv/vendor/bundle/ruby/2.3.0/gems/listen-3.0.8/lib
...
from/home/alex/.rbenv/versions/2.3.1/lib/ruby/site\u ruby/2.3.0/rubygems/core\u ext/kernel\u require.rb:59:in'require'
from-e:1:in`'

我不知道如何解决这个问题。感谢您的帮助

更新1：

---

最后，我找到了这个邪恶bug的来源——尽管如此，我还是指定了Rails 5.1.1，当我运行Rails新应用程序_name时，它会安装5.1.6！似乎它使用了5.1.6 gem依赖项。。。仍然不知道如何解决而不是升级到>=5.1.6

将以下行添加到您的GEM文件中

gem'rails'，5.1.1'

---

运行

bundle install

您能再次尝试

bundle uninstall ffi

和

bundle install

吗？如果您得到“找不到命令uninstall”，似乎您不小心跳过了

bundle

。尝试

捆绑卸载ffi

而不是

卸载ffi

。下次你可以试试。但很高兴听到你的问题解决了：）@AlexanderGorgIn在您的gem文件中，添加行

gem rails，'5.1.1'

@akaspinnaka谢谢，就这样！我必须指定版本！请修改你的答案，这样我就可以接受了！更新了答案@AlexanderGorg