[Seaside] Fwd: [MAGMA] Image Grow[FIX] [!!] [PIM]

[Giovanni Giorgi]

Hi all! I forward here a problem about Magma.
When using Magma and Seaside, you can get an Image Grow. I have found 
the problem is inside Magma, and I hav provided here a small solution,
with the foreword of Chris Muller (Magma Author)

--- Giovanni Giorgi <jj at objectsroot.com> wrote:
> Hi Chris!
> I have done a simple method to purge magma session.
> 
> Chris Muller wrote:
> [...]
> 
> >Also, unfortunately, there is a known bug I haven't been able to figure out.
> > I think it might be a Squeak limitation but I'm not sure.  If you are familiar
> >with the mechanics of MethodContexts and BlockContexts, perhaps you will
> have
> >an easy answer!  First, this simple script demonstrates the problem:
> >  
> >
> Hem....I am not so strong in MethodContexts ;(
> 
> >[...]
> >Do you or anyone else know how to get hold of these MethodContexts
> >programmatically?  If so, I can put this clean-up as part of the disconnect.
> >
> >I'm sorry this problem has affected you, I hope we can find a solution.
> >  
> >
> Do not worry. I will find a solution ;) with my....personal way... ;)
> [gio si prying the Squeak Gods....
>     Alan&Dan Can we help us?!?!?]
> 
> I have done a small method:
> ====================================
> purgeMagmaSessions
>     | ms |
>     "PIMDB purgeMagmaSessions"
>     ms _ MagmaSession allInstances.
>     Transcript cr; show: ms size asString.
>     "First Step:"
>     ms  do: [ : each | each become: String new ].
>     "Second strong step:"
>     ms _ MagmaSession allInstances.
>     ms
>         do: [:elem | elem isConnected
>                 ifFalse: [| objList |
>                     objList _ Smalltalk pointersTo: elem.
>                     objList
>                         do: [:mc | mc class == MethodContext
>                                 ifTrue: [ mc receiver: nil. Transcript 
> show:'#'.]
>                                 ifFalse: [ "Transcript cr; show: 
> 'Excluding:' , mc asString"]]]].
>     Smalltalk garbageCollect.
>     Transcript cr; show: ms size asString.
> ====================================
> This method is very very crude and can lead problems because uses a very 
> simple idea to work.
> My image started with 114 magma sessions and ended up with 0 sessions !!!
> You should wait a little and/or try it two times.
> Can you review it and incorporate in the next magma release?
> 



-------- Response Message of prev. email. --------
Subject: 	[Q] How do I reset a MethodContext? (was: [MAGMA] Image Grow 
[PIM] [DANGEROUS?])
Date: 	Tue, 21 Oct 2003 14:39:41 -0700 (PDT)
From: 	Chris Muller <afunkyobject at yahoo.com>
Reply-To: 	chris at funkyobjects.org, The general-purpose Squeak developers 
list <squeak-dev at lists.squeakfoundation.org>
To: 	giovanni.giorgi at siforge.org, Squeak List 
<squeak-dev at lists.squeakfoundation.org>



I'm glad you found a work-around.  As you said, this is a crude solution that I
don't think is suitable for Magma.  We need to find a "correct" solution.

To do that, though, I need to understand the nature of BlockContexts and
MethodContexts and how and when their receiver gets set.  I imagine, when the
block is executed, slots that were allocated at compile time to hold certain
external references are populated.  That's why, without true BC's, we can't
execute a Block more than once at a time (because the variables would get
overlayed with the second execution).

So this will probably get fixed with VI4 / true BC's.  When is that?

Until then, let's see if we can come up with a non-Magma example of the
problem, then maybe someone can help us out with it.

The three blocks in MagmaSession>>initializeSerializer appear to be the ones
retaining the state of their last execution.  Let me know if you are able to
reproduce the problem simply in a pristine 3.6gamma.  I'll see if I can too.

Regards,
  Chris

[...]




-- 
  [   [  [ JJ ]  ]   ]  | First, they ignore you. Then they laugh  
                        | at you. Then they fight you. Then you win
http://www.siforge.org  |          Mahatma Ghandi