Bug #6425: Psych issue with !!omap

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-linux]

[trans (Thomas Sawyer)]

=begin

Psych doesn't seem to know ordered map. It parses fine, but loose the type when round-tripped.

a = YAML.load %{
--- !!omap
a: 1
b: 2
}
=> {"a"=>1, "b"=>2}
a.class
=> Hash
puts a.to_yaml

a: 1
b: 2

=end

• File noname noname added

On Sat, May 12, 2012 at 04:55:08AM +0900, trans (Thomas Sawyer) wrote:

Issue #6425 has been reported by trans (Thomas Sawyer).

---

Bug #6425: Psych issue with !!omap
https://bugs.ruby-lang.org/issues/6425

Author: trans (Thomas Sawyer)
Status: Open
Priority: Normal
Assignee:
Category: lib
Target version:
ruby -v: ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-linux]

=begin

Psych doesn't seem to know ordered map. It parses fine, but loose the type when round-tripped.

a = YAML.load %{
--- !!omap
a: 1
b: 2
}
=> {"a"=>1, "b"=>2}
a.class
=> Hash
puts a.to_yaml

a: 1
b: 2

=end

Are you sure this is Psych and not Syck? Psych raises a syntax error on
your example:

 irb(main):001:0> require 'psych'
 => true
 irb(main):002:0> require 'yaml'
 => true
 irb(main):003:0> a = YAML.load %{
 irb(main):004:0"   --- !!omap
 irb(main):005:0"   a: 1
 irb(main):006:0"   b: 2
 irb(main):007:0" }
 Psych::SyntaxError: (<unknown>): mapping values are not allowed in this context at line 3 column 4
         from /Users/aaron/.local/lib/ruby/2.0.0/psych.rb:203:in `parse'
         from /Users/aaron/.local/lib/ruby/2.0.0/psych.rb:203:in `parse_stream'
         from /Users/aaron/.local/lib/ruby/2.0.0/psych.rb:151:in `parse'
         from /Users/aaron/.local/lib/ruby/2.0.0/psych.rb:127:in `load'
         from (irb):3
         from /Users/aaron/.local/bin/irb:12:in `<main>'
 irb(main):008:0>

Can you provide a runnable test case to reproduce your error?

--
Aaron Patterson
http://tenderlovemaking.com/

[trans (Thomas Sawyer)]

=begin

Ah, the indention I added was the problem. Try:

a = YAML.load %{
--- !!omap
a: 1
b: 2
}
a.class
a.to_yaml

As for a test case. Something like?

class TestYAMLOMap < Test::Unit::TestCase
def test_omap_round_trip
a = YAML.load "--- !!omap\n"a: 1\nb: 2\n"
s = a.to_yaml
assert s.index('!!omap')
end
end

Okay, it could be better, but it's a start.
=end

[trans (Thomas Sawyer)]

Btw, just thought of something that might be important here. Technically a YAML OMap type is written:

--- !!omap

• a: 1
• b: 2

The additional array sequence ensures the order regardless of the parser. However, given Ruby's ordered hashes, it makes sense that it can handle both the array (sequence) and the hash (mapping) forms.

• File noname noname added

On Tue, May 15, 2012 at 08:45:05AM +0900, trans (Thomas Sawyer) wrote:

Issue #6425 has been updated by trans (Thomas Sawyer).

=begin

Ah, the indention I added was the problem. Try:

a = YAML.load %{
--- !!omap
a: 1
b: 2
}
a.class
a.to_yaml

Perfect. I can verify this is a bug. Thanks for reporting it!

--
Aaron Patterson
http://tenderlovemaking.com/

[tenderlovemaking (Aaron Patterson)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r35657.
Thomas, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

• ext/psych/lib/psych/visitors/to_ruby.rb: convert omap tagged maps to
  Psych::Omap objects rather than hashes. [Bug #6425]

• test/psych/test_omap.rb: pertinent test.