Issue #14475 has been updated by sam.saffron (Sam Saffron).
"If the string is frozen, then return the string itself."
Yeah I do not agree with this documentation, I think it should be changed.
Trouble is that there is no simple way to de-duplicate unconditionally without either inefficiency or side effects:
Say `x` is an arbitrary string (either frozen or unfrozen) :
```
x = -x # may return a non fstring
x = -+x # will return fstring, but makes an unneeded copy
x = -x.dup # fstring again, uneeded copy
x = x.frozen? ? -+x : -x # too verbose
```
Instead why not change it so `-` deduped unconditionally?
----------------------------------------
Bug #14475: String de-duplication is broken in files with frozen_string_literal: true
https://bugs.ruby-lang.org/issues/14475#change-70352
* Author: sam.saffron (Sam Saffron)
* Status: Open
* Priority: Normal
* Assignee:
* Target version:
* ruby -v: 2.5.0, 2.6.0
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
----------------------------------------
Create 2 files:
test.rb
```
$LOAD_PATH.unshift(File.dirname(__FILE__))
require 'frozen'
puts frozen.object_id
puts frozen.object_id
```
frozen.rb
```
# frozen_string_literal: true
A = "a"
def frozen
-"#{A}"
end
```
Run `test.rb`
```
% ruby test.rb
70189973179400
70189973179260
```
Change to `# frozen_string_literal: false`
And you get
```
70189973181360
70189973181360
```
So something is over-optimising here, fix should be backported to 2.5.0 imo.
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