[ruby-core:95647] [Ruby master Feature#16150] Add a way to request a frozen string from to_s
From:
rafael@...
Date:
2019-11-01 23:37:59 UTC
List:
ruby-core #95647
Issue #16150 has been updated by rafaelfranca (Rafael Fran=E7a). This issue is also fixed on Rails 5.2 and will be released in the next vers= ion of Rails. Users of any version of Rails below 5.2 are already abandoned. The Rails co= re team don't support those versions anymore. So, they already need to upgr= ade their applications, with this change or not. We could still say that users would still need to upgrade to Rails 6.0.1 be= cause of this change but in my opinion that is already required. Users that= stay on Rails 6.0.0 would not receive security upgrades without having to = upgrade to 6.0.1 (or the latest version before the security patch) first. ---------------------------------------- Feature #16150: Add a way to request a frozen string from to_s https://bugs.ruby-lang.org/issues/16150#change-82435 * Author: headius (Charles Nutter) * Status: Closed * Priority: Normal * Assignee: Eregon (Benoit Daloze) * Target version: = ---------------------------------------- Much of the time when a user calls to_s, they are just looking for a simple= string representation to display or to interpolate into another string. In= my brief exploration, the result of to_s is rarely mutated directly. It seems that we could save a lot of objects by providing a way to explicit= ly request a *frozen* string. For purposes of discussion I will call this to_frozen_string, which is a te= rrible name. This would reduce string allocations dramatically when applied to many comm= on to_s calls: * Symbol#to_frozen_string could always return the same cached String repres= entation. This method is *heavily* used by almost all Ruby code that interm= ingles Symbols and Strings. * nil, true, false, and any other singleton values in the system could simi= larly cache and return the same String object. * The strings coming from core types could also be in the fstring cache and= deduplicated as a result. * User-provided to_s implementations could opt-in to caching and returning = the same frozen String object when the author knows that the result will al= ways be the same. A few ideas for what to call this: * `to_fstring` or `fstring` reflects internal the "fstring" cache but is pe= rhaps not obvious for most users. * `to_s(frozen: true)` is clean but there will be many cases when the kwarg= s hash doesn't get eliminated, making matters worse. * `def to_s(frozen =3D false)` would be mostly free but may not be compatib= le with existing to_s params (like `Integer#to_s(radix)` This idea was inspired by @schneems's talk at RubyConf Thailand, where he s= howed significant overhead in ActiveRecord from Symbol#to_s allocation. -- = https://bugs.ruby-lang.org/ Unsubscribe: <mailto:[email protected]?subject=3Dunsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>