Help: Does anyone use legacy message box behavior?

[Richard Gaskin]

Monte Goulding wrote:

 >> On 8 Feb 2017, at 11:02 am, Richard Gaskin wrote:
 >>
 >> Monte Goulding wrote:
 >> > ...You might think we don’t need to touch it but it has
 >> > been touched recently because of a change in the way we
 >> > retain object references.
 >>
 >> Now I'm curious: anything interesting there in terms of features,
 > performance, or memory handling?
 >
 > The main advantage is stability.

That's a feature.  And a good one.  In my community meeting with Peter 
last week he outlined some of the effort going into v9 stability 
improvements, and I was quite impressed.

 > You might remember that in one of the early 8 releases (not sure
 > which one as it was just before I started) the memory management
 > of objects changed so they would be released sooner if deleted
 > within tight script loops instead of waiting for the next main
 > loop to released them. It was a response to a bug where creating
 > and deleting lots of objects in a loop bloated memory use I believe.
 > Well deleting them earlier resulted in *lots* of instability where
 > there were references to objects (say the internal defaultStack
 > global for example) but the object had been deleted. Things like
 > scripts still executing on objects that are meant to be deleted
 > or setting the defaultStack to a stack that has just been deleted.
 > Anyway in order to make it easier for us to resolve these issues
 > Fraser wrote a class to use as an object handle whenever we want
 > to keep a reference to an object. So now we can do stuff like
 > t_stack.IsValid() before doing something with t_stack.
 >
 > For example one crash that I just fixed is this one: 
https://github.com/livecode/livecode/pull/5143 
<https://github.com/livecode/livecode/pull/5143>
 >
 > In that crash we were getting the stack of an object when it is being
 > sent a message then using it later but the particular crashing code
 > was deleting the stack the target object was on in a frontScript
 > which was executed between getting the reference to the stack and
 > using it. So the change now uses an object handle so we can check
 > it’s still valid before sending the message after the frontScripts
 > are executed ;-)

Sounds like a very good change.  Thanks for that background.  Even 
though I almost never write in C anymore, that under-the-hood stuff is 
very helpful for understanding how the engine works.



 >> Thanks for running this by the community.
 >
 > It’s worth remembering that almost all of what we do is run by the
 > community because everyone is free to subscrib to our github feed
 > and comment on our PRs.

An excellent reminder.  The Github tools have made the process 
wonderfully visible.

-- 
  Richard Gaskin
  Fourth World Systems
  Software Design and Development for the Desktop, Mobile, and the Web
  ____________________________________________________________________
  Ambassador at FourthWorld.com                http://www.FourthWorld.com