Issue #20652 has been updated by byroot (Jean Boussier).
I don't really like a Regexp flag for this because a Regexp might be used in different contexts and some usages might want $~ and some might not (which could lead to a bunch of duplication).
I see what you mean, but such flag would only really be worth using in places where saving that allocation is worth it, where right now you usually use a literal anyway, so I don't think duplication would be a concern. Of course you could expect Rubocop and such to try to force it on everyone because it's faster™, but... ---------------------------------------- Misc #20652: Memory allocation for gsub has increased from Ruby 2.7 to 3.3 https://bugs.ruby-lang.org/issues/20652#change-109231 * Author: orisano (Nao Yonashiro) * Status: Open * Assignee: jeremyevans0 (Jeremy Evans) ---------------------------------------- I recently upgraded from ruby 2.7.7 to 3.3.1 and noticed that the GC load increased. When I used the allocation profiler to investigate, I found that memory allocation from gsub had increased. The problem was code like this: ```ruby s = "foo " s.gsub(/ (\s+)/) { " #{' ' * Regexp.last_match(1).length}" } ``` When I compared the results of heap-profiler between 2.7.7 and 3.3.1, I found that MatchData was increasing. https://gist.github.com/orisano/98792dee260106e9b6fcb45bbabeb1e6 https://github.com/ruby/ruby/commit/abc0304cb28cb9dcc3476993bc487884c139fd11 I discovered that the cause is this commit, which stopped reusing backref to avoid race conditions. Is there a way to reuse backref while still avoiding race conditions? -- https://bugs.ruby-lang.org/