由于 readline 中的错误，当我按下按钮时，Rails 脚本/控制台崩溃

Question

这个问题是间歇性的，但是按向上箭头来获取以前输入的命令我会得到一个错误，例如：

/Users/me/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-2.3.14/lib/active_support/whiny_nil.rb:52:in `method_missing': undefined method `force_encoding' for nil:NilClass (NoMethodError)
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:3801:in `_rl_col_width'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:2944:in `update_line'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:3486:in `block in rl_redisplay'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:3481:in `each'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:3481:in `rl_redisplay'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:4618:in `_rl_internal_char_cleanup'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:4679:in `readline_internal_charloop'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:4743:in `readline_internal'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:4765:in `readline'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/readline.rb:40:in `readline'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/input-method.rb:115:in `gets'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:139:in `block (2 levels) in eval_input'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:273:in `signal_status'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:138:in `block in eval_input'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:188:in `call'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:188:in `buf_input'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:103:in `getc'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/slex.rb:205:in `match_io'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/slex.rb:75:in `match'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:286:in `token'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:262:in `lex'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:233:in `block (2 levels) in each_top_level_statement'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:229:in `loop'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:229:in `block in each_top_level_statement'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:228:in `catch'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:228:in `each_top_level_statement'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:155:in `eval_input'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:70:in `block in start'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:69:in `catch'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:69:in `start'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/bin/irb:16:in `<main>'

看起来问题出在 readline 中？如何解决问题？根据bundle list我有这个版本的readline：

• rb-readline (0.4.2)

更新：使用rvm pkg install readline 更新后出现新错误：

>/Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:2730:in `[]': no implicit conversion from nil to integer (TypeError)
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:2730:in `update_line'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:3486:in `block in rl_redisplay'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:3481:in `each'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:3481:in `rl_redisplay'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:4618:in `_rl_internal_char_cleanup'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:4679:in `readline_internal_charloop'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:4743:in `readline_internal'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/rbreadline.rb:4765:in `readline'
    from /Users/me/.rvm/gems/ruby-1.9.3-p194/gems/rb-readline-0.4.2/lib/readline.rb:40:in `readline'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/input-method.rb:115:in `gets'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:139:in `block (2 levels) in eval_input'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:273:in `signal_status'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:138:in `block in eval_input'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:188:in `call'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:188:in `buf_input'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:103:in `getc'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/slex.rb:205:in `match_io'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/slex.rb:75:in `match'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:286:in `token'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:262:in `lex'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:233:in `block (2 levels) in each_top_level_statement'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:229:in `loop'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:229:in `block in each_top_level_statement'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:228:in `catch'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb/ruby-lex.rb:228:in `each_top_level_statement'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:155:in `eval_input'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:70:in `block in start'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:69:in `catch'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:69:in `start'
    from /Users/me/.rvm/rubies/ruby-1.9.3-p194/bin/irb:16:in `<main>'

我仍然遇到旧错误。

Answer 1

这显然是 rb-readline 的问题。

我通常将 readline 安装为 rvm 包：

rvm pkg install readline

并且不要在我的 Gemfile 中使用任何 readline 特定的东西。

你也可以看看：

Problems with the rails console, RVM and readline

Answer 2

我今天遇到了。

我相信这是因为 readline 试图解析控制台行上的一些文本。有些文字播放不好。

那么为什么要向上键呢？

这恰好是在我粘贴大量“东西”来设置变量之后。由于控制台崩溃了，我显然在粘贴时出错了。

所有 IT 专业人员在发生崩溃后都会做什么？再试一次。尝试您在 rails 控制台中编写的最后一个命令的最快方法是什么？向上键。

解决此问题的一个好办法是简单地不按向上键或清除历史记录以删除有问题的行。