[ruby-core:100462] [Ruby master Feature#17256] Freeze all Regexp objects

[daniel@dan42.com]

Issue #17256 has been updated by Dan0042 (Daniel DeLorme).


Given that string literals with interpolation were recently unfrozen, it would appear slightly inconsistent to freeze regexp literals with interpolation.
`/#{str}/` is equivalent to `Regexp.new(str)` so I would find it a bit weird if they had a different behavior w/r freezing. It would make more sense to say that _all_ new regexps (including `Regexp.new` and `Regexp.compile`) are frozen. That way all constants such as `UNSAFE = Regexp.new("[^#{SAFE_STRING}]", false)` would be automatically ractor-safe.

And if someone really needs to modify a regexp maybe they can use `dup`?
`rx = Regexp.new(str).dup.extend(PrintWhenMatch)`

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Feature #17256: Freeze all Regexp objects
https://bugs.ruby-lang.org/issues/17256#change-88081

* Author: ko1 (Koichi Sasada)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
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To be shared between ractors, Regexp objects should be frozen.

Now, Matz has proposed to make all Regexp objects frozen.

Ten months ago, there was a note https://bugs.ruby-lang.org/issues/16377#note-7 :

> For the record: Regexp.new should continue to return unfrozen Regexp instance.

So I'm not sure whether it is a good way or not.

Could you give me your comment on it?

If no comments are given, I'll try to freeze them before Ruby 3.0 preview 2.

BTW, I believe `/#{expr}/o` should be frozen because this expression only returns one Regexp object.




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