Make `$SAFE` process global state and allow to set 0 again
$SAFE > 1 is removed from Ruby 2.3 and there are some opinion to remove
$SAFE feature ([Feature #5455]).
There are several reason, but the biggest reason I think is nobody use
$SAFE is thread/proc local information and it hurts performance (we need to restore
$SAFE information just after returning proc, even if returning by exception).
$SAFE == 1 is similar to warning and it is not a security feature, but one of the programming tool we can use to improve our program (
$SAFE == 3 was for sandbox, security feature).
From this perspective, Matz approved us the followings:
$SAFEis process global, not a Proc local state.
- We can set
$SAFE == 0when
$SAFE == 1.
I think we can't make big project with the above changes (how to make multi-thread programming with this
$SAFE seems for small project (so-called scripting). Anyway if nobody use it, no problem on these changes.
I will commit this change soon.
Please try new spec and point out any problem you got.