[Octave-bug-tracker] [bug #54319] saving a classdef to a MAT file then loading it crashes Octave

[Sébastien Villemot]

URL:
  <http://savannah.gnu.org/bugs/?54319>

                 Summary: saving a classdef to a MAT file then loading it
crashes Octave
                 Project: GNU Octave
            Submitted by: svillemot
            Submitted on: Mon 16 Jul 2018 04:53:43 PM UTC
                Category: Interpreter
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 4.4.0
        Operating System: GNU/Linux

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Details:

Hi,

Assume you have defined the following trivial classdef:

classdef NumValue
   properties
      Number = 1
   end
end


Then the following sequence crashes Octave:

octave:1> a = NumValue()
a =

<object NumValue>

octave:2> save -mat foo.mat a
warning: struct: converting a classdef object into a struct overrides the
access restrictions defined for properties. All properties are returned,
including private and protected ones.
warning: struct: converting a classdef object into a struct overrides the
access restrictions defined for properties. All properties are returned,
including private and protected ones.
octave:3> load foo.mat
octave-gui: libinterp/octave-value/ov-class.cc:1070: bool
octave_class::reconstruct_exemplar(): Assertion `have_ctor' failed.
fatal: caught signal Aborted -- stopping myself...
Aborted


The problem is that Octave tries to reload the object as if it was a legacy
class, instead of a classdef.

I attach a draft patch that prevents the crash and make Octave return a
struct.

Ideally Octave should rather return a classdef value (see also bug #45833). I
would be willing to write such a patch, but I would ideally need some guidance
(concerning the complexity of the task and the pitfalls to avoid).

Best,




    _______________________________________________________

File Attachments:


-------------------------------------------------------
Date: Mon 16 Jul 2018 04:53:43 PM UTC  Name: classdef-mat-load.patch  Size:
726B   By: svillemot

<http://savannah.gnu.org/bugs/download.php?file_id=44564>

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