[ruby-core:117028] [Ruby master Bug#20319] Singleton class is being frozen lazily in some cases

Issue #20319 has been updated by Eregon (Benoit Daloze). Alternatively, I think we could simplify `Kernel#freeze` to always only freeze the direct object and no other object, i.e. no singleton class would be frozen when freezing a singleton object. State and methods are separate things, so IMO it doesn't gain anything to freeze singleton classes of a singleton object on `singleton_object.freeze`. The methods can still be modified e.g. using `singleton_object.class.class_exec { def foo = 42 }`. I think Kernel#freeze should only freeze the object itself, which means instance variables (and internal state if core/TypedStruct object) cannot be changed. That would be both more consistent semantically and more efficient, while avoiding weird cases like the above. ---------------------------------------- Bug #20319: Singleton class is being frozen lazily in some cases https://bugs.ruby-lang.org/issues/20319#change-107097 * Author: andrykonchin (Andrew Konchin) * Status: Open * ruby -v: 3.2.2 * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- I've noticed suspicious behaviour (it doesn't affect anything in practice for me though) when an object becomes frozen only its own singleton class becomes frozen immediately. A singleton class of the object immediate singleton class becomes frozen lazily after `#singleton_class` method call: ```ruby o = Object.new klass = o.singleton_class.singleton_class o.freeze puts klass.frozen? # false <== here we expect true puts o.singleton_class.singleton_class.frozen? # true puts klass.frozen? # true ``` I would expect all created (and visible to user) singleton classes in an object singleton classes chain to become frozen immediately when the object gets frozen. -- https://bugs.ruby-lang.org/