Issue #8977 has been updated by charliesome (Charlie Somerville).

Target version set to current: 2.1.0

I would love to see this feature in 2.1.

These are the top duplicated strings in an app I work on:

irb(main):023:0> GC.start; h = ObjectSpace.each_object(String).to_a.group_by { |s| s }.map{ |s, objs| [s, objs.size] }; h.sort_by { |s, count| -count }.take(10).each do |s| p s end; nil
["/", 5241]
["(eval)", 3207]
["application", 2389]
["", 1908]
["html.erb", 1720]
["base64", 1520]
["erb", 1464]
["IANA", 1389]
["initialize", 1147]
["recognize", 1036]

Most of these could be deduplicated with String#frozen.
----------------------------------------
Feature #8977: String#frozen that takes advantage of the deduping 
https://bugs.ruby-lang.org/issues/8977#change-42198

Author: sam.saffron (Sam Saffron)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: current: 2.1.0


During memory profiling I noticed that a large amount of string duplication is generated from non pre-determined strings.

Take this report for example https://gist.github.com/SamSaffron/6789005 (generated using the memory_profiler gem that works against head) 

">=" x 4953
    /Users/sam/.rbenv/versions/2.1.0-dev/lib/ruby/2.1.0/rubygems/requirement.rb:93 x 4535

This string is most likely extracted from a version. 

Or 

"/Users/sam/.rbenv/versions/2.1.0-dev/lib/ruby/gems" x 5808
    /Users/sam/.rbenv/versions/2.1.0-dev/lib/ruby/gems/2.1.0/gems/activesupport-3.2.12/lib/active_support/dependencies.rb:251 x 3894

A string that can not be pre-determined. 

---- 


It would be nice to have 

"hello,world".split(",")[0].frozen.object_id == "hello"f.object_id 

Adding #frozen will give library builders a way of using the de-duping. It also could be implemented using weak refs in 2.0 and stubbed with a .dup.freeze in 1.9.3 . 

Thoughts ?  





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