#4875 OrderedHash#invert returns an unordered hash - Ruby on Rails

Type	To find
responsible:me	tickets assigned to you
tagged:"@high"	tickets tagged @high
milestone:next	tickets in the upcoming milestone
state:invalid	tickets with the state invalid
created:"last week"	tickets created last week
sort:number, importance, updated	tickets sorted by #, importance or updated
Combine keywords for powerful searching.
Use advanced searching »

This project is archived and is in readonly mode.

#4875 ✓resolved

OrderedHash#invert returns an unordered hash

Reported by Chris Griego | June 16th, 2010 @ 08:36 PM | in 3.0.2

ActiveSupport::OrderedHash#invert will return an hash of indeterminate order, which is inconsistent with Ruby 1.9.

>> a = {"foo" => "FOO", "bar" => "BAR", "baz" => "BAZ"}
=> {"baz"=>"BAZ", "foo"=>"FOO", "bar"=>"BAR"}
>> b = ActiveSupport::OrderedHash[[["foo", "FOO"], ["bar", "BAR"], ["baz", "BAZ"]]]
=> #<OrderedHash {"baz"=>"BAZ", "foo"=>"FOO", "bar"=>"BAR"}>
>> a.keys
=> ["baz", "foo", "bar"]
>> b.keys
=> ["foo", "bar", "baz"]
>> a.invert
=> {"BAZ"=>"baz", "FOO"=>"foo", "BAR"=>"bar"}
>> b.invert
=> {"BAZ"=>"baz", "FOO"=>"foo", "BAR"=>"bar"}
>> a.invert.invert
=> {"baz"=>"BAZ", "foo"=>"FOO", "bar"=>"BAR"}
>> b.invert.invert
=> {"baz"=>"BAZ", "foo"=>"FOO", "bar"=>"BAR"}

Comments and changes to this ticket

chaitanyav June 26th, 2010 @ 06:22 AM

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.

You flagged this item as spam.
chaitanyav June 26th, 2010 @ 06:23 AM
- no changes were found...

chaitanyav June 26th, 2010 @ 06:29 AM

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.

You flagged this item as spam.
Chris Griego June 26th, 2010 @ 06:40 AM
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.
You flagged this item as spam.
chaitanyav June 26th, 2010 @ 07:53 AM
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
```
Rohit Arondekar June 26th, 2010 @ 07:59 AM
- Importance changed from “” to “Low”
chaitanyav, I've edited your posts for formating. Please wrap code/console output like things in @@@. See http://help.lighthouseapp.com/faqs/getting-started/how-do-i-format-... for more information.
Rohit Arondekar June 26th, 2010 @ 08:04 AM
- State changed from “new” to “incomplete”
- Milestone cleared.
Can one of you start working on a patch with tests?
You flagged this item as spam.
chaitanyav June 26th, 2010 @ 09:58 AM
Attached is the patch with tests,
- ordered_hash_invert_patch.diff 1.5 KB
Rohit Arondekar June 26th, 2010 @ 11:03 AM
- Tag changed from “activesupport, orderedhash” to “activesupport, orderedhash, patch”
- State changed from “incomplete” to “verified”
- Assigned user set to “José Valim”
+1 Applies cleanly & tests pass.
Repository June 26th, 2010 @ 11:11 AM
(from [9958950f78638e4a6c6800404d84f22effc0748e]) Add OrderedHash#invert to preserve order in ruby 1.8 [#4875]

Signed-off-by: José Valim jose.valim@gmail.com
http://github.com/rails/rails/commit/9958950f78638e4a6c6800404d84f2...
Repository June 26th, 2010 @ 11:11 AM
- State changed from “verified” to “resolved”
(from [aa48ab05f40788bd9f54124f91b0ad86869a7b06]) 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 state:resolved] http://github.com/rails/rails/commit/aa48ab05f40788bd9f54124f91b0ad...
You flagged this item as spam.
Chris Griego June 26th, 2010 @ 04:00 PM
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?
José Valim June 26th, 2010 @ 04:46 PM
Chris, how are you applying the commits? Using git cherry-pick? For some reason, it's creating conflicts here.
You flagged this item as spam.
Chris Griego June 26th, 2010 @ 04:57 PM
I was using cherry-pick. I just tried chaitanyav's patch file and that applied cleanly as well for me.
Repository June 26th, 2010 @ 05:17 PM
(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 state:resolved] http://github.com/rails/rails/commit/0e9190c902d075c70e2f54096ae554...
Jeremy Kemper October 15th, 2010 @ 11:01 PM
- Milestone set to “3.0.2”
[bulk edit]