[PD-dev] deadly leak

[Jonathan Wilkes]

HiKrzysztof,
     I believe Ivica fixed this bug in Pd-l2ork back in March.  From http://l2ork.music.vt.edu/data/pd/Changelog:
*fixed problem where doubly-nested gops still caused double-entry bug after cut/undo inside the abstraction.


I haven't run into the double-entry problem in Pd-l2ork since then, but I can confirm it's still a problem in 0.43.

-Jonathan


----- Original Message -----
> From: Krzysztof Czaja <czaja at chopin.edu.pl>
> To: pd-dev <pd-dev at iem.at>
> Cc: 
> Sent: Monday, December 12, 2011 8:15 PM
> Subject: [PD-dev] deadly leak
> 
> Hi Pd gurus,
> 
> ever found a single keystroke or a mouse click was duplicated
> on a patch?  A strange bug which always turns out to be fatal
> at the point of closing the patch?
> 
> Hit by several such crashes one after another I went hunting.
> 
> What I found was that there is always a t_editor created for
> a GOP graph.  The constructor is invoked by the first
> glist_findrtext() call aimed at anything inside of that GOP
> (this occurs when the parent is being mapped).
> 
> Thus, the editor_new() for a GOP is called, but the
> corresponding editor_free() seems never to be called.
> 
> The reason why this is not an innocent leak, but a crasher
> is quite subtle.
> 
> For any t_editor, there is a t_guiconnect object created and
> bound to a symbol made up from the address of the editor's
> owner (a glist).  Since the editor is zombiefied, so is the
> guiconnect, and the symbol is never unbound.
> 
> The trouble begins when another canvas is allocated at the
> address freed by the late owner of the zombie.  The editor is
> created, and a new t_guiconnect is bound to the old symbol.
> 
> Now, if any message is sent to the symbol, it is caught by
> two t_guiconnect objects, both pointing to the same address:
> their 'x_who' pointer.  Hence, all messages from pd-gui to
> the new canvas are duplicated.  The agony is terminated by
> the second copy of the message 'menuclose'.
> 
> I believe this bug has never been dealt with.  So, in case
> you consider it worthwhile, could someone forgive me my
> slothfulness and file this thing into the sf.net bug tracker
> or open a github's issue, whichever is more appropriate
> these days.
> 
> Krzysztof
> 
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