Issue #20290 has been updated by kjtsanaktsidis (KJ Tsanaktsidis). Thanks Peter, that all sounds reasonable to me.
If we want to use this feature for general bound library destruction, it's better that this feature is invoked even when RUBY_FREE_AT_EXIT isn't 1.
Hm. I wonder if extension developers should themselves check if RUBY_FREE_AT_EXIT is set when deciding what to do in their `Destruct_` functions. Obviously they shouldn't be calling `getenv` and doing this parsing themselves, but maybe a parameter or function can be exposed where developers can do "important" cleanup unconditionally, but "optional" cleanup only if memory leak checking is on. I don't have a strong idea about what's "important" vs "optional" though. ---------------------------------------- Feature #20290: Add API for C extensions to free memory https://bugs.ruby-lang.org/issues/20290#change-106959 * Author: peterzhu2118 (Peter Zhu) * Status: Open ---------------------------------------- GitHub PR: https://github.com/ruby/ruby/pull/10055 Ticket #19993 added the new feature RUBY_FREE_AT_EXIT, which frees memory in Ruby at shutdown. This allowed tools like Valgrind, ASAN, and macOS leaks to find memory leaks in Ruby without a large number of false-positives outputted. However, this feature is not complete for C extensions, as they may also need to free their memory and there was no way to do so. This means that C extensions might not be able to directly use tools like Valgrind, ASAN, or macOS leaks to find memory leaks. This ticket proposes an API for C extensions to free memory by defining a function called `Destruct_<extension name>` that is called during shutdown when RUBY_FREE_AT_EXIT is enabled. This name mirrors the `Init_<extension name>` API that already exists for extension initialization. However, unlike the `Init_<extension name>` function, `Destruct_<extension name>` is NOT mandatory for the C extension to implement so that we can preserve backwards compatibility. -- https://bugs.ruby-lang.org/