Feature #8906: Freeze Symbols

• Status: Closed
• Assignee: matz (Yukihiro Matsumoto)
• Target version: 2.1.0

[ko1 (Koichi Sasada)]

Now, Integer and Float objects are frozen objects.
How about to freeze Symbol objects, too?
I think Symbol is friend of Integer.

Current behavior:
p :foo.frozen? #=> false
:foo.instance_variable_set(:@foo, 1)
p :foo.instance_variable_get(:@foo) #=> 1

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Background of this proposal:

Now, I'm working on "GC-able Symbols" feature.
Freezing symbols make this feature easier.

for example:
(1) set an instance variable @iv for symbol s
(2) collect s
(3) generate s
(4) what value of @iv for s returns?

[matz (Yukihiro Matsumoto)]

Symbol is a symbol is a symbol. It's not a string, nor an integer.

Besides that, I agree with making symbols frozen.

Matz.

[headius (Charles Nutter)]

+1. Anything that can't be extended and whose regular state can't be mutated (not counting user-provided instance vars and such) should be frozen.

Cool, I love frozen stuff!

[ko1 (Koichi Sasada)]

• Status changed from Open to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r42974.
Koichi, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

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• include/ruby/ruby.h: make Symbol objects frozen.
  [Feature #8906]
  I want to freeze this good day, too.
• test/ruby/test_eval.rb: catch up this change.
• test/ruby/test_symbol.rb: add a test to check frozen symbols.