ActiveSupport::JSON.decode dies on double escaped string

Say the content of a file is this: {"a":"\/\/\/\/\/","b":"2009-03-17 14:20:42",some_key Then reading that string with File.open("file_name").read yields this string: "{"a":"\/\/\/\/\/","b":"2009-03-17 14:20:42",some_key Decoding this string with ActiveSupport::JSON.decode goes wrong, the resulting hash: {"a"=>"/////", "b"=>"2009 03-17 14:20:42", "s me_key"=>"some_value"}

Notice the hyphen between 2009-03 is missing as well as the 'o' in the 'some_key' word.

I believe this is due to the fact that the string read from the file is double escaped. The in combination with the date matching causes the wrong characters to be replaced with a space which in some cases leads to a mangled result and in other cases in invalid JSON strings.

A quick fix is to replace the '\/' sequences in the string which resulted from the file read with '/'. Example: ActiveSupport::JSON.decode(File.open("some_file").gsub!('\/','/'))

I still believe this is a bug.

bug by Harm Aarts is "not reproducible" .

Can reproduce bug by okkez

Before patch by Bas van Klinkenberg (https://rails.lighthouseapp.com/projects/8994/tickets/2831)

h = { "data" => [{"key" => "漢字", "date" => "2008-01-01"}, {"key" => "あいう", "date" => "2009-01-01", "date2" => "2009-01-02"}]}
=> {"data"=>[{"key"=>"漢字", "date"=>"2008-01-01"}, {"key"=>"あいう", "date"=>"2009-01-01", "date2"=>"2009-01-02"}]}
>> ActiveSupport::JSON.decode(h.to_json)
IndexError: index 118 out of string
    from /home/jastix/projects/bugmash/bookclub/vendor/rails/activesupport/lib/active_support/json/backends/yaml.rb:77:in `[]='
    from /home/jastix/projects/bugmash/bookclub/vendor/rails/activesupport/lib/active_support/json/backends/yaml.rb:77:in `block in convert_json_to_yaml'
    from /home/jastix/projects/bugmash/bookclub/vendor/rails/activesupport/lib/active_support/json/backends/yaml.rb:77:in `each'
    from /home/jastix/projects/bugmash/bookclub/vendor/rails/activesupport/lib/active_support/json/backends/yaml.rb:77:in `convert_json_to_yaml'
    from /home/jastix/projects/bugmash/bookclub/vendor/rails/activesupport/lib/active_support/json/backends/yaml.rb:16:in `decode'
    from /home/jastix/projects/bugmash/bookclub/vendor/rails/activesupport/lib/active_support/json/decoding.rb:11:in `decode'
    from (irb):45
    from /usr/local/bin/irb:12:in `'

After patch:

h = { "data" => [{"key" => "漢字", "date" => "2008-01-01"}, {"key" => "あいう", "date" => "2009-01-01", "date2" => "2009-01-02"}]}
=> {"data"=>[{"key"=>"漢字", "date"=>"2008-01-01"}, {"key"=>"あいう", "date"=>"2009-01-01", "date2"=>"2009-01-02"}]}

ActiveSupport::JSON.decode(h.to_json) => {"data"=>[{"key"=>"漢字", "date"=>Tue, 01 Jan 2008}, {"key"=>"あいう", "date"=>Thu, 01 Jan 2009, "date2"=>Fri, 02 Jan 2009}]}

Duplicate of #2831