From: eregontp@... Date: 2019-11-05T21:30:39+00:00 Subject: [ruby-core:95710] [Ruby master Feature#16150] Add a way to request a frozen string from to_s Issue #16150 has been updated by Eregon (Benoit Daloze). naruse (Yui NARUSE) wrote: > As already Matz stated, I reverted this at bea322a3. So you reverted without a single case that was actually problematic due to the change? I'm very disappointed, deprecation without a proper explanation seems inappropriate. I expect a clear explanation of why this is problematic. It is not problematic for the case of Rails, as clearly explained in the comments above. @matz On what did you base your decision? I hope something else than a single unclear bug report. ---------------------------------------- Feature #16150: Add a way to request a frozen string from to_s https://bugs.ruby-lang.org/issues/16150#change-82494 * Author: headius (Charles Nutter) * Status: Open * 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 explicitly request a *frozen* string. For purposes of discussion I will call this to_frozen_string, which is a terrible name. This would reduce string allocations dramatically when applied to many common to_s calls: * Symbol#to_frozen_string could always return the same cached String representation. This method is *heavily* used by almost all Ruby code that intermingles Symbols and Strings. * nil, true, false, and any other singleton values in the system could similarly 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 always be the same. A few ideas for what to call this: * `to_fstring` or `fstring` reflects internal the "fstring" cache but is perhaps not obvious for most users. * `to_s(frozen: true)` is clean but there will be many cases when the kwargs hash doesn't get eliminated, making matters worse. * `def to_s(frozen = false)` would be mostly free but may not be compatible with existing to_s params (like `Integer#to_s(radix)` This idea was inspired by @schneems's talk at RubyConf Thailand, where he showed significant overhead in ActiveRecord from Symbol#to_s allocation. -- https://bugs.ruby-lang.org/ Unsubscribe: