From: shibata.hiroshi@...
Date: 2014-01-30T06:17:20+00:00
Subject: [ruby-core:60312] [ruby-trunk - Feature #8977] String#frozen that takes advantage of the deduping

Issue #8977 has been updated by Hiroshi SHIBATA.

Target version changed from 2.1.0 to current: 2.2.0

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Feature #8977: String#frozen that takes advantage of the deduping 
https://bugs.ruby-lang.org/issues/8977#change-44803

* Author: Sam Saffron
* Status: Assigned
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* Category: 
* Target version: current: 2.2.0
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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. 

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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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