OrderedHash#invert returns an unordered hash

It's working correctly

neo@myhost awesome]$ irb
irb(main):001:0> require 'active_support'
=> true
irb(main):002:0> a = ActiveSupport::OrderedHash.new
=> {}
irb(main):003:0> a["1"] = 2
=> 2
irb(main):004:0> a["3"] = 4
=> 4
irb(main):005:0> a["5"] = 6
=> 6
irb(main):006:0> a
=> {"1"=>2, "3"=>4, "5"=>6}
irb(main):007:0> a.class
=> ActiveSupport::OrderedHash
irb(main):008:0> a.invert
=> {2=>"1", 4=>"3", 6=>"5"}
irb(main):009:0> a.invert.invert
=> {"1"=>2, "3"=>4, "5"=>6}

rb(main):010:0> b = Hash.new
=> {}
irb(main):011:0> b["1"] = 2
=> 2
irb(main):012:0> b["3"] = 4
=> 4
irb(main):013:0> b["5"] = 6
=> 6
irb(main):014:0> b
=> {"1"=>2, "3"=>4, "5"=>6}
irb(main):015:0> b.invert.invert
=> {"1"=>2, "3"=>4, "5"=>6}

BTW, I am using Ruby 1.9.2 and Rails 3 Beta 4

Edited by Rohit Arondekar for formating.

Also checked it your example.

irb(main):022:0> b = ActiveSupport::OrderedHash[[["foo", "FOO"], ["bar", "BAR"], ["baz", "BAZ"]]]
=> {"foo"=>"FOO", "bar"=>"BAR", "baz"=>"BAZ"}
irb(main):023:0> a = {"foo" => "FOO", "bar" => "BAR", "baz" => "BAZ"}
=> {"foo"=>"FOO", "bar"=>"BAR", "baz"=>"BAZ"}
irb(main):024:0> a.invert.invert
=> {"foo"=>"FOO", "bar"=>"BAR", "baz"=>"BAZ"}
irb(main):025:0> b.invert.invert
=> {"foo"=>"FOO", "bar"=>"BAR", "baz"=>"BAZ"}
irb(main):026:0>

It works as intended.

Hashes in Ruby 1.9 are ordered by default and ActiveSupport::OrderedHash simply inherits its ordered behavior from Hash when the Ruby version is >= 1.9. ActiveSupport::OrderedHash exists to support ordered behavior in Ruby 1.8.

Chris the instance method invert returns a new Hash,

In Ruby 1.9 since the ordering is preserved in Hash, it wont matter. But the 'invert' method needs to be overridden in OrderedHash for Ruby 1.8

irb(main):003:0> a = ActiveSupport::OrderedHash.new
=> {}
irb(main):004:0> a["1"] = 2
=> 2
irb(main):005:0> a["3"] = 4
=> 4
irb(main):006:0> a
=> {"1"=>2, "3"=>4}
irb(main):007:0> a.class
=> ActiveSupport::OrderedHash
irb(main):008:0> a.invert.class
=> Hash

Attached is the patch with tests,

(from [9958950f78638e4a6c6800404d84f22effc0748e]) Add OrderedHash#invert to preserve order in ruby 1.8 [#4875 OrderedHash#invert returns an unordered hash]

Signed-off-by: José Valim jose.valim@gmail.com
http://github.com/rails/rails/commit/9958950f78638e4a6c6800404d84f2...

Thanks chaitanyav for the patch!

José Valim, the three commits also apply cleanly to the 2-3-stable branch with passing tests. Would you backport them?

Chris, how are you applying the commits? Using git cherry-pick? For some reason, it's creating conflicts here.

I was using cherry-pick. I just tried chaitanyav's patch file and that applied cleanly as well for me.

(from [0e9190c902d075c70e2f54096ae55476ed47b6a3]) Tidy up tests in previous commit since they did not assure an OrderedHash is returned (the test would pass for an array and would pass by chance for hashes).

[#4875 OrderedHash#invert returns an unordered hash state:resolved] http://github.com/rails/rails/commit/0e9190c902d075c70e2f54096ae554...