rails 4: 在第 2 行第 11 列 (Psych::SyntaxError) 的上下文中不允许映射值？答案

【问题标题】：rails 4: mapping values are not allowed in this context at line 2 column 11 (Psych::SyntaxError)?rails 4: 在第 2 行第 11 列 (Psych::SyntaxError) 的上下文中不允许映射值？
【发布时间】：2013-09-08 16:01:19
【问题描述】：

我已成功安装 rails 4 并使用 rails 4.0.0 创建项目

rails s

第一次运行良好。但是在 gemfile 中添加 'devise' gem 之后

 gem 'devise', '~> 3.0.0.rc'

并运行捆绑安装，我收到以下错误。这个错误的原因是什么，解决方法是什么？

我也尝试过评论 gem 'devise' 部分，但现在每个 rails 命令都出现相同的错误。

/home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:205:in `parse':   (<unknown>): mapping values are not allowed in this context at line 2 column 11 (Psych::SyntaxError)
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:205:in `parse_stream'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:153:in `parse'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:129:in `load'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/config_file.rb:318:in `load_file'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/config_file.rb:191:in `initialize'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/gem_runner.rb:66:in `new'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/gem_runner.rb:66:in `do_configuration'
from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/rubygems/gem_runner.rb:46:in `run'

database.yml 文件

development:
adapter: mysql2
encoding: utf8
database: realstate_development
pool: 5
username: root
password: root
socket: /var/run/mysqld/mysqld.sock

gem 'devise' 与任何版本，捆绑显示以下错误，如果我删除 devise gem 它工作正常，我使用 rails 3.2.13 但我从未遇到过这样的问题，真奇怪。

Fetching gem metadata from https://rubygems.org/.........
Fetching gem metadata from https://rubygems.org/..
Unfortunately, a fatal error has occurred. Please see the Bundler troubleshooting documentation at http://bit.ly/bundler-issues. Thanks!
/home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:205:in `parse': (<unknown>): mapping values are not allowed in this context at line 2 column 11 (Psych::SyntaxError)
    from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:205:in `parse_stream'
    from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:153:in `parse'
    from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/2.0.0/psych.rb:129:in `load'
    from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/config_file.rb:318:in `load_file'
    from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems/config_file.rb:191:in `initialize'
    from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:319:in `new'
    from /home/siv/.rvm/rubies/ruby-2.0.0-p247/lib/ruby/site_ruby/2.0.0/rubygems.rb:319:in `configuration'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/rubygems_integration.rb:34:in `configuration'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/rubygems_integration.rb:53:in `sources='
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/source/rubygems.rb:250:in `remote_specs'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/source/rubygems.rb:163:in `fetch_specs'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/source/rubygems.rb:67:in `specs'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/definition.rb:192:in `block (2 levels) in index'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/definition.rb:189:in `each'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/definition.rb:189:in `block in index'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/index.rb:9:in `build'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/definition.rb:185:in `index'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/definition.rb:179:in `resolve'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/definition.rb:114:in `specs'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/definition.rb:109:in `resolve_remotely!'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/installer.rb:83:in `run'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/installer.rb:14:in `install'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/cli.rb:247:in `install'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/vendor/thor/task.rb:27:in `run'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/vendor/thor/invocation.rb:120:in `invoke_task'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/vendor/thor.rb:344:in `dispatch'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/vendor/thor/base.rb:434:in `start'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/bin/bundle:20:in `block in <top (required)>'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/lib/bundler/friendly_errors.rb:3:in `with_friendly_errors'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/gems/bundler-1.3.5/bin/bundle:20:in `<top (required)>'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/bin/bundle:23:in `load'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247@global/bin/bundle:23:in `<main>'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `eval'
    from /home/siv/.rvm/gems/ruby-2.0.0-p247/bin/ruby_noexec_wrapper:14:in `<main>'

【问题讨论】：

能否请您也发布您的 database.yml 文件？
人们通常通过编辑发布附加文件
bundle install 也引发了与此错误消息相同的错误：不幸的是，发生了致命错误。请参阅 bit.ly/bundler-issues 的 Bundler 故障排除文档。谢谢！我关注了bit.ly/bundler-issues，但没有解决方案。
问题出在一个（或多个）yaml 文件中，如果 Psych gem 引发异常，可能在项目中的 database.yml 中。
您确定每个环境的所有设置都缩进遵循 yaml 语法吗？

标签： ruby-on-rails devise rubygems gem ruby-on-rails-4

【解决方案1】：

如果有人仍然遇到同样的错误，您可以检查项目中的 YAML 文件。在此示例中，问题是 database.yml 中缺少缩进。它应该是这样的：

development:
  adapter: mysql2
  encoding: utf8
  database: realstate_development
  pool: 5
  username: root
  password: root
  socket: /var/run/mysqld/mysqld.sock

我得到了同样的错误，但出于其他原因，整个问题出在不正确的 application.yml

中

【讨论】：

对我来说，问题是我的 YAMl 中有一个格式错误的字符串。当我需要host: local 时，我有host: local:。希望这可以帮助其他人解决这个问题。

【解决方案2】：

首先注意 yml 文件，其中 parse 方法由于 Psych::SyntaxError 而失败。然后在文件中查找以下内容

YAML 文件应该正确缩进并且必须遵循正确的语法。
1.列表的所有成员都是以“-”（破折号和空格）开头的相同缩进级别开始的行：
2.字典是以简单的键：值形式表示（冒号后面必须跟一个空格）：
有关更多语法相关信息，请查看以下链接：http://docs.ansible.com/ansible/YAMLSyntax.html

【讨论】：