Issue #20792 has been updated by Eregon (Benoit Daloze). I think I discussed this with @byroot a couple times as well, what about `String#with_encoding(Encoding)`, which is like `force_encoding` but doesn't mutate the receiver. Then this would be efficient in that it would scan the code range once: ```ruby utf8 = binary_str.with_encoding(Encoding::UTF_8) if utf8.valid_encoding? return utf8 else return binary_str end ``` And of course it would shorten `str.dup.force_encoding(Encoding::UTF_8)` to `str.with_encoding(Encoding::UTF_8)`. ---------------------------------------- Feature #20792: String#forcible_encoding? https://bugs.ruby-lang.org/issues/20792#change-110112 * Author: kddnewton (Kevin Newton) * Status: Open ---------------------------------------- I would like to add a method to String called `forcible_encoding?(encoding)`. This would return true or false depending on whether the receiver can be forced into the given encoding without breaking the string. It would effectively be an alias for: ```ruby def forcible_encoding?(enc) original = encoding result = force_encoding(enc).valid_encoding? force_encoding(original) result end ``` I would like this method because there are extremely rare but possible circumstances where source files are marked as binary but contain UTF-8-encoded characters. In that case I would like to check if it's possible to cleanly force UTF-8 before actually doing it. The code I'm trying to replace is here: https://github.com/ruby/prism/blob/d6e9b8de36b4d18debfe36e4545116539964ceeb/.... The pull request for the code is here: https://github.com/ruby/ruby/pull/11851. -- https://bugs.ruby-lang.org/