* Use the wrapper of rb_cObject instead of data access
* Replaced rest of extentions
* Updated the version guard for Data
* Added the version guard of rb_cData
Introduce new method Ractor.make_shareable(obj) which tries to make
obj shareable object. Protocol is here.
(1) If obj is shareable, it is shareable.
(2) If obj is not a shareable object and if obj can be shareable
object if it is frozen, then freeze obj. If obj has reachable
objects (rs), do rs.each{|o| Ractor.make_shareable(o)}
recursively (recursion is not Ruby-level, but C-level).
(3) Otherwise, raise Ractor::Error. Now T_DATA is not a shareable
object even if the object is frozen.
If the method finished without error, given obj is marked as
a sharable object.
To allow makng a shareable frozen T_DATA object, then set
`RUBY_TYPED_FROZEN_SHAREABLE` as type->flags. On default,
this flag is not set. It means user defined T_DATA objects are
not allowed to become shareable objects when it is frozen.
You can make any object shareable by setting FL_SHAREABLE flag,
so if you know that the T_DATA object is shareable (== thread-safe),
set this flag, at creation time for example. `Ractor` object is one
example, which is not a frozen, but a shareable object.
Former ROBJECT_IV_INDEX_TBL macro included RCLASS_IV_INDEX_TBL, which is
not disclosed to extension libraies. The macro was kind of broken. Why
not just deprecate it, and convert the internal use into an inline
function.
RARRAY_AREF has been a macro for reasons. We might not be able to
change that for public APIs, but why not relax the situation internally
to make it an inline function.
Assertions in header files slows down an interpreter, so they should be
turned off by default (simple `make`). To enable them, define a macro
`RUBY_DEBUG=1` (e.g. `make cppflags=-DRUBY_DEBUG` or use `#define` at
the very beggining of the file. Note that even if `NDEBUG=1` is defined,
`RUBY_DEBUG=1` enables all assertions.
[Feature #16837]
related: https://github.com/ruby/ruby/pull/3120
`assert()` lines in MRI *.c is not disabled even if `RUBY_DEBUG=0` and
it can be disabled with `NDEBUG=1`. So please consider to use
`RUBY_ASSERT()` if you want to disable them when `RUBY_DEBUG=0`.
