Re: [bugs #8498] [MinGW] NSUnarchiver crashes

[Gregory John Casamento]

All,

Initial tests indicate that this breaks .gorm loading for some reason.   I need
to do further tests.   I recommend not adding this patch until this problem has
been investigated and cleared.

GJC

--- Willem Rein Oudshoorn <noreply@savannah.gnu.org> wrote:
> This mail is an automated notification from the bugs tracker
>  of the project: GNUstep.
> 
> /**************************************************************************/
> [bugs #8498] Latest Modifications:
> 
> Changes by: 
>               Willem Rein Oudshoorn <woudshoo@xs4all.nl>
> 'Date: 
>               Fri 04/09/04 at 10:29 (Europe/Amsterdam)
> 
> ------------------ Additional Follow-up Comments ----------------------------
> The attached patch should fix this.  
> It will retain the objects in the objMap and release them
> when clearing the map.   But note that we really need 
> to be carefull when retaining the objects, otherwise code like
> 
> - initWithCoder:..
> {
>    [self dealloc];
>    return something_else;
> }
> 
> will crash the unarchiver.  
> This rules out the replacement of objMap with an 
> NSArray.  
> 
> If nobody objects I will commit this shortly.
> 
> Wim Oudshoorn.
>  
> 
> 
> 
> 
> 
> 
> 
> /**************************************************************************/
> [bugs #8498] Full Item Snapshot:
> 
> URL: <http://savannah.gnu.org/bugs/?func=detailitem&item_id=8498>
> Project: GNUstep
> Submitted by: Willem Rein Oudshoorn
> On: Thu 04/08/04 at 09:45
> 
> Category:  Base/Foundation
> Severity:  3 - Ordinary
> Item Group:  Bug
> Resolution:  None
> Assigned to:  wim
> Status:  Open
> 
> 
> Summary:  [MinGW] NSUnarchiver crashes
> 
> Original Submission:  It seems that if you call release on an decoded object
> that is shared with other objects lead to a crash.
> 
> In particular:
> 
> Obj1 ---> string
> Obj2 ----/
> 
> and if in initWithCoder of Obj1 (and Obj2) we have:
> 
> [coder decodeValuesOfObjCType: "@", &string];
> [string release];
> 
> the decoding crashes.  
> The funny thing is that this seems to be a windows
> specific problem.  It works fine on Linux.
> 
> The attached program will demonstrate the problem:
> 
> ./TestCoder Encode test.enc
> 
> this will create test.enc  
> 
> ./TestCoder Decode test.enc
> 
> which decodes the created test.enc.  This crashes
> on MinGW but not on Linux and the generated
> files test.enc are identical, so it is probably
> in de unarchiving code.
> 
> 
> 
> 
> Follow-up Comments
> ------------------
> 
> 
> -------------------------------------------------------
> Date: Fri 04/09/04 at 10:29         By: wim
> The attached patch should fix this.  
> It will retain the objects in the objMap and release them
> when clearing the map.   But note that we really need 
> to be carefull when retaining the objects, otherwise code like
> 
> - initWithCoder:..
> {
>    [self dealloc];
>    return something_else;
> }
> 
> will crash the unarchiver.  
> This rules out the replacement of objMap with an 
> NSArray.  
> 
> If nobody objects I will commit this shortly.
> 
> Wim Oudshoorn.
>  
> 
> 
> -------------------------------------------------------
> Date: Thu 04/08/04 at 11:58         By: wim
> Actually, it is a generic bug, Linux is just lucky!
> The bug is as follows:
> NSUnarchiver has an ivar, "objMap" which is a map
> from "ref" to "Objects".  However the the "Objects"
> are NOT retained.  This means that if they are deallocated
> the reference in this map becomes invalid.   Solution is
> to retain the objects in this map.
> 
> 
> 
> 
> 
> 
> 
> File Attachments
> -------------------
> 
> -------------------------------------------------------
> Date: Fri 04/09/04 at 10:29  Name: NSUnarchiver.patch  Size: 1KB   By: wim
> Patch to retain temporary the objects so initwithcoder can release them
> http://savannah.gnu.org/bugs/download.php?item_id=8498&amp;item_file_id=1177
> 
> -------------------------------------------------------
> Date: Thu 04/08/04 at 09:45  Name: testCoder.tar.bz2  Size: 1KB   By: wim
> Demonstrating crash.
> http://savannah.gnu.org/bugs/download.php?item_id=8498&amp;item_file_id=1173
> 
> 
> 
> 
> 
> 
> For detailed info, follow this link:
> <http://savannah.gnu.org/bugs/?func=detailitem&item_id=8498>
> 
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=====
Gregory John Casamento -- CEO/President Open Logic Corp.

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