bugGNU Octave - Bugs: bug #46497, classdef: delete destructor method...

 
 

bug #46497: classdef: delete destructor method is not called when clearing handle class

Submitted by:  None
Submitted on:  Sun 22 Nov 2015 09:01:54 PM UTC
 
Category:  Interpreter Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Matlab Compatibility
Status:  Fixed Assigned to:  None
Originator Name:  Marco Merlin Originator Email:  -email is unavailable-
Open/Closed:  * Closed Release:  * dev
Operating System:  * Any
* Mandatory Fields

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Thu 21 Feb 2019 10:58:03 PM UTC, comment #6: 

I think we can close this as Octave 5 is releasing soon. The delete method is called now. There are other open issues (e.g. bug #53844), we can file and work on related issues in other bug reports.

Mike Miller <mtmiller>
Project Administrator
Tue 22 May 2018 05:45:07 PM UTC, comment #5: 

I don't think this was reverted completely on the stable branch, the code that was added in b328ff3ce0f7 and 56201aad3462 is still present in the cdef_object_rep::release function. The delete method is still being called when an object is cleared.

Mike Miller <mtmiller>
Project Administrator
Tue 15 May 2018 08:06:10 PM UTC, comment #4: 

Due to a number of issues that were discovered after 4.4.0 was release, I had no other real choice than to undo this change.  A proper fix will have to wait until at least version 5.

http://hg.savannah.gnu.org/hgweb/octave/rev/61ba501d8f04

John W. Eaton <jwe>
Project Administrator
Fri 27 Apr 2018 02:00:22 AM UTC, comment #3: 

Piotr: I pushed your change.  That uncovered a bug in the evaluator that I introduced with my big refactor last year.  Then I realized that Octave would crash if an exception was thrown in the delete method, so I fixed that with the same technique as is used in the octave_oncleanup destructor.  The final set of patches are:

http://hg.savannah.gnu.org/hgweb/octave/rev/4a46c83bcb71
http://hg.savannah.gnu.org/hgweb/octave/rev/b328ff3ce0f7
http://hg.savannah.gnu.org/hgweb/octave/rev/56201aad3462

maintainers: I know it's very late for this kind of thing, but I pushed on stable because having a working delete method makes handle classes substantially more useful and the bug in the evaluator was serious trouble waiting to happen.

John W. Eaton <jwe>
Project Administrator
Thu 02 Nov 2017 06:14:33 PM UTC, comment #2: 

And I tested it as extensively as I could with no side effects.

The destructor is called only when clearing an object that inherits from handle and not when a classdef does not inherit from handle.

The way I arrived at this solution was to turn on DEBUG_TRACES in ov-classdef.cc and then I found the location where the handle_cdef_object destructor is called. That's where I added the cdef_class::delete_object() function which calls the classdef "delete()" method.

I also wrote a tests for the problem.

The patch filename is:
patch_classdef_destructor_bug46497.diff

(file #42322)

Piotr Held <jsoh425>
Sat 28 Nov 2015 11:33:27 AM UTC, comment #1: 

I can confirm the issue on Octave 4.0.0 and ubuntu.

Anonymous
Sun 22 Nov 2015 09:01:54 PM UTC, original submission:  

I have created a superclass inheriting from handle, an example here:

classdef myClass < handle
    methods
        function delete(obj)
        disp('delete was called');
        end
    end
end

Here is the Matlab behavior, sticking to my expectations, deleting the class when clearing the reference.

>> c = myClass

c =

  myClass with no properties.

>> clear c
delete was called
>>

On the contrary, Octave does not execute the delete method.

>> c = myClass
c =

<object myClass>

>> clear c
>>

Similarly, following suggestion from here
http://stackoverflow.com/questions/14057308/matlab-class-destructor-not-called-during-clear, I have tried to use the onCleanup event

classdef myClass_cleanup < handle
  properties
    cleanup;
  end

    methods
        function obj = myClass_cleanup()
          obj.cleanup = onCleanup(@()delete(obj));
        end

        function delete(obj)
        disp('delete was called');
        end
    end
end

Here is what Matlab does, even though it is not clear now what actually triggers the destructor.

>> c = myClass_cleanup
c =

<object myClass_cleanup>

>> clear c
>>

And here is Octave still happily avoiding the destructor.

>> c = myClass_cleanup
c =

<object myClass_cleanup>

>> clear c
>>

Anonymous

 

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Attach Files:
   
   
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Attached Files
file #35522:  myClass.m added by None (131B - text/x-objcsrc)
file #35523:  myClass_cleanup.m added by None (289B - text/x-objcsrc)

 

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  • -email is unavailable- added by amro_octave
  • -email is unavailable- added by jwe (Posted a comment)
  • -email is unavailable- added by jsoh425 (Updated the item)
  • -email is unavailable- added by cbm
  • -email is unavailable- added by None (Submitted the item)
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    Follow 19 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-02-21 mtmiller Carbon-CopyRemoved mtmiller => -
    2019-02-21 mtmiller Carbon-CopyRemoved 80942 => -
    2019-02-21 mtmiller StatusPostponed => Fixed
        Open/ClosedOpen => Closed
    2018-10-10 amro_octave Carbon-Copy- => Added amro_octave
    2018-10-08 mtmiller Dependencies- => bugs #54800 is dependent
    2018-05-22 mtmiller Dependencies- => bugs #53844 is dependent
    2018-05-22 mtmiller Dependencies- => bugs #53956 is dependent
    2018-05-15 jwe StatusReady For Test => Postponed
    2018-04-27 jwe StatusConfirmed => Ready For Test
    2017-11-02 jsoh425 Attached File- => Added patch_classdef_destructor_bug46497.diff, #42322
    2016-06-02 mtmiller StatusNone => Confirmed
        Release4.0.0 => dev
        Operating SystemMicrosoft Windows => Any
        Summarydelete class destructor is not called when clearing handle class => classdef: delete destructor method is not called when clearing handle class
    2016-05-26 cbm Carbon-Copy- => Added cbm
        Carbon-Copy- => Added mtmiller
    2015-11-22 None Attached File- => Added myClass.m, #35522
        Attached File- => Added myClass_cleanup.m, #35523

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