From: chopraanmol1@...
Date: 2018-10-24T13:07:04+00:00
Subject: [ruby-core:89549] [Ruby trunk Feature#15251] Hash aset should deduplicate non tainted string

Issue #15251 has been reported by chopraanmol1 (Anmol Chopra).

----------------------------------------
Feature #15251: Hash aset should deduplicate non tainted string
https://bugs.ruby-lang.org/issues/15251

* Author: chopraanmol1 (Anmol Chopra)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I'm not sure if current behavior is expected one or a bug. So fell free to change tracker type.

Currently Hash aset checks if non-tainted string exists in fstring table or not, if it does not then ruby duplicates string and freeze it. This works well for string_literal because they are already registered in fstring table during compilation, but it doesn't work for non-string literal.

Patch

https://github.com/ruby/ruby/pull/1993

O/P of attached file on trunk:
~~~
string_literal => 1
string times 1 => 1
string times 3 string times 3 string times 3  => 100
interpolated_string => 100
string add => 100
string append => 100
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
fstring
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
string_literal => 1
string times 1 => 1
string times 3 string times 3 string times 3  => 1
interpolated_string => 1
string add => 1
string append => 1
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
fstring + GC
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
string_literal => 1
string times 1 => 1
string times 3 string times 3 string times 3  => 100
interpolated_string => 100
string add => 100
string append => 100
~~~

after patch
~~~
string_literal => 1
string times 1 => 1
string times 3 string times 3 string times 3  => 1
interpolated_string => 1
string add => 1
string append => 1
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
fstring
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
string_literal => 1
string times 1 => 1
string times 3 string times 3 string times 3  => 1
interpolated_string => 1
string add => 1
string append => 1
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
fstring + GC
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
string_literal => 1
string times 1 => 1
string times 3 string times 3 string times 3  => 1
interpolated_string => 1
string add => 1
string append => 1
~~~



---Files--------------------------------
test_hash_keys_deduped.rb (927 Bytes)


-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>