Ruby

Fix writebarrier in backtrace_initialize_copy

Fix write barrier in update_classvariable_cache

Fix writebarrier on rb_class_set_box_classext

Update mark bits as we go in ibf load

We're allocating as we fill in the ISEQ, which could cause GC, so we
need to be careful values are marked and use write barriers.

When we were loading values here we were issuing write barriers, however
if the iseq was to be marked at the time it wouldn't mark the these...

Issue writebarrier_remember after set const tbl

Add write barriers on Hash#rehash

Hide ractor traversal object hash

This could contain other hidden objects, and so needs to be hidden
itself so as to not be seen by ObjectSpace.each_object

1000.times { ObjectSpace.each_object(Hash){|o| puts o.inspect; ObjectSpace.reachable_objects_from(Class) } }'...

Add and use rb_ivar_foreach_buffered

Previously, rb_ivar_foreach would walk up the shape tree, but yield
instance variables to the callback as it went. If the object shape was
modified during this callback, particularly with removing an instance
variable, it could result in reading free'd memory....

Fix iv_count for too_complex generic ivar

Previously this branch forgot to assign iv_count when used with a
generic ivar which is too_complex, which could result in it incorrectly
returning 0.

[DOC] Clarify array methods using eql?

[Bug #22013]

Up to a certain size, only eql? is used, but for larger arrays
a Hash is used an #hash becomes necessary.

We could consider always checking #hash for consistency, but
that would decrease performance....