Issue #20937 has been updated by byroot (Jean Boussier). The current `rb_str_set_len` behavior was added in https://github.com/ruby/ruby/commit/8965ed167dbca9471ccc41e9bebe7e2fb1fa9fcb... by @nobu, but there is no associated bug report or anything so it's unclear to me whether making the string independent there is acceptable or not. ---------------------------------------- Bug #20937: "can't set length of shared string" error when using OpenSSL::Cipher#update with buffer https://bugs.ruby-lang.org/issues/20937#change-110915 * Author: akiellor (Andrew Kiellor) * Status: Open * Assignee: rhenium (Kazuki Yamaguchi) * ruby -v: ruby 3.3.6 (2024-11-05 revision 75015d4c1f) +YJIT [arm64-darwin23] * Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- We've observed a recurring "can't set length of shared string" error in production emerging from the `aws-sdk-s3` library when using it's client encryption features. The sdk in this mode uses OpenSSL::Cipher in decrypt mode with a String buffer. It appears that under some circumstances the buffer becomes a "shared string" and is no longer compatible with the requirements of OpenSSL::Cipher#update. I've attached a reproduction scenario using only the ruby standard library. ``` shell $ ruby -v ruby 3.3.6 (2024-11-05 revision 75015d4c1f) +YJIT [arm64-darwin23] $ ruby scripty.rb scripty.rb:32:in `update': can't set length of shared string (RuntimeError) from scripty.rb:32:in `block (2 levels) in <main>' from scripty.rb:31:in `each' from scripty.rb:31:in `block in <main>' from /nix/store/fhmbmmzr4h5yax66nl2x44rrdf039b3s-ruby-3.3.6/lib/ruby/3.3.0/tempfile.rb:447:in `create' from scripty.rb:26:in `<main>' ``` The attached script has a few different read patterns, some fail and some do not. Credit for isolating this issue goes to [@simoleone](https://bugs.ruby-lang.org/users/55425). ---Files-------------------------------- scripty.rb (1.15 KB) -- https://bugs.ruby-lang.org/