ruby-on-rails - Bundler 找不到 gem 的兼容版本，正在更新 Rails 应用程序

Question

创建一个全新的 Rails 应用程序之后关注官方 Rails 博客 post ，尝试将应用程序转换为 rails 3.2.0.rc2 会产生以下结果

Updated Gemfile to depend on rails ~> 3.2.0.rc2
    gem 'rails', '~>3.2.0.rc2'
Updated Gemfile to depend on sass-rails ~> 3.2.3
    gem 'sass-rails',   '~> 3.2.3'

$ bundle install
Fetching source index for http://rubygems.org/
Bundler could not find compatible versions for gem "activesupport":
  In snapshot (Gemfile.lock):
    activesupport (3.1.1)

  In Gemfile:
    rails (~> 3.2.0.rc2) ruby depends on
      activesupport (= 3.2.0.rc2) ruby

Running `bundle update` will rebuild your snapshot from scratch, using 
only the gems in your Gemfile, which may resolve the conflict.

$bundle update
Fetching source index for http://rubygems.org/
Bundler could not find compatible versions for gem "railties":
  In Gemfile:
    coffee-rails (~> 3.1.1) ruby depends on
      railties (~> 3.1.0) ruby

    rails (~> 3.2.0.rc2) ruby depends on
      railties (3.2.0.rc2)

到底是什么问题？

系统规范:

Mac OS 10.7.2、Xcode 4.2.1、rvm 1.10.1 使用 ruby​​ 1.9.3p0(2011-10-30 修订版 33570)[x86_64-darwin11.2.0]

Answer 1

我通过删除锁 rm Gemfile.lock 并再次运行 bundle install 解决了这个问题:

$ rm Gemfile.lock
$ bundle install
Using rake (0.9.2.2) 
Using i18n (0.6.0) 
Using multi_json (1.0.4) 
Using activesupport (3.2.0.rc2) 
Using builder (3.0.0) 
Using activemodel (3.2.0.rc2) 
Using erubis (2.7.0) 
Using journey (1.0.0) 
Using rack (1.4.0) 
Using rack-cache (1.1) 
Using rack-test (0.6.1) 
Using hike (1.2.1) 
Using tilt (1.3.3) 
Using sprockets (2.1.2) 
Using actionpack (3.2.0.rc2) 
Using mime-types (1.17.2) 
Using polyglot (0.3.3) 
Using treetop (1.4.10) 
Using mail (2.3.0) 
Using actionmailer (3.2.0.rc2) 
Using arel (3.0.0) 
Using tzinfo (0.3.31) 
Using activerecord (3.2.0.rc2) 
Using activeresource (3.2.0.rc2) 
Using bundler (1.0.21) 
Using coffee-script-source (1.2.0) 
Using execjs (1.2.13) 
Using coffee-script (2.2.0) 
Using rack-ssl (1.3.2) 
Using json (1.6.4) 
Using rdoc (3.12) 
Using thor (0.14.6) 
Using railties (3.2.0.rc2) 
Using coffee-rails (3.2.1) 
Using jquery-rails (2.0.0) 
Using rails (3.2.0.rc2) 
Using sass (3.1.12) 
Using sass-rails (3.2.3) 
Using sqlite3 (1.3.5) 
Using uglifier (1.2.2) 
Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.

这是解决问题的一种相当蛮力的方法。如果这是一个已建立的项目，您可能会在删除 Gemfile.lock 后遇到其他问题，因为依赖版本不再被锁定。但是，如果这是一个新项目，采用这种方法不太可能会遇到问题。