[bug #68594] Regression in MAT-file loading breaks GUIDE applications

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URL:=0A  <https://savannah.gnu.org/bugs/?68594>=0A=0A                 Summa=
ry: Regression in MAT-file loading breaks GUIDE=0Aapplications=0A          =
         Group: GNU Octave=0A               Submitter: hg200=0A            =
   Submitted: Tue 04 Aug 2026 06:12:25 AM UTC=0A                Category: C=
lassdef=0A                Severity: 3 - Normal=0A                Priority: =
5 - Normal=0A              Item Group: Regression=0A                  Statu=
s: None=0A             Assigned to: None=0A         Originator Name: HG200=
=0A        Originator Email:=0A             Open/Closed: Open=0A         Di=
scussion Lock: Unlocked=0A                 Release: stable=0A        Operat=
ing System: Any=0A           Fixed Release: None=0A         Planned Release=
: None=0A=0A=0A    _______________________________________________________=
=0A=0AFollow-up Comments:=0A=0A=0A-----------------------------------------=
--------------=0ADate: Tue 04 Aug 2026 06:12:25 AM UTC By: Hg200 <hg200>=0A=
Hello,=0A=0AI encountered a regression when trying to run GUIDE application=
s. When running=0Aa GUIDE application, Octave fails with=0A=0Awarning: load=
: object of class 'function_handle_workspace' was deleted in=0AMATLAB and c=
annot be loaded. Returning metadata=0Awarning: called from=0A    hgload at =
line 73 column 3=0A    openfig at line 120 column 3=0A    gui_mainfcn at li=
ne 43 column 7=0A    untitled at line 12 column 7=0A=0Awarning: load: class=
def not found. Element loaded as uint32=0Awarning: called from=0A    hgload=
 at line 73 column 3=0A    openfig at line 120 column 3=0A    gui_mainfcn a=
t line 43 column 7=0A    untitled at line 12 column 7=0A        =0Aerror: s=
et: new children list must be a permutation of existing children with=0Avis=
ible handles=0Aerror: called from=0A    struct2hdl>setprops at line 700 col=
umn 10=0A    struct2hdl at line 231 column 3=0A    struct2hdl at line 225 c=
olumn 8=0A    hgload at line 105 column 5=0A    openfig at line 120 column =
3=0A    gui_mainfcn at line 43 column 7=0A    untitled at line 12 column 7=
=0A=0AI bisected the problem and found that it first appears at changeset=
=0A34833:df257404f3e8 "Support load and save for classdef objects in MAT-fi=
les=0A(bug #45833)". At this revision, loading the .fig file fails:=0A=0A>>=
 hg=3Dload('untitled.fig');=0Awarning: load: classdef not found. Element lo=
aded as uint32=0Aerror: octave_base_value::map_value(): wrong type argument=
 'uint32 matrix'=0A>> whos -file untitled.fig=0Awarning: load: classdef not=
 found. Element loaded as uint32=0Aerror: octave_base_value::map_value(): w=
rong type argument 'uint32 matrix'=0A=0AStepping back to 34831:bcc9c5609193=
 the same GUIDE application runs correctly.=0ALoading the .fig file works a=
s expected:=0A=0A>> hg=3Dload('untitled.fig');=0A>> whos -file untitled.fig=
=0AVariables in the file untitled.fig:=0A=0Avariables in scope: untitled.fi=
g=0A=0A  Attr   Name            Size                     Bytes  Class=0A  =
=3D=3D=3D=3D   =3D=3D=3D=3D            =3D=3D=3D=3D                     =3D=
=3D=3D=3D=3D  =3D=3D=3D=3D=3D=0A         hgM_070000      1x1               =
          24  struct=0A         hgS_070000      1x1                       6=
550  struct=0A         meta_data       1x1                        104  stru=
ct=0A=0ATotal is 3 elements using 6678 bytes=0A=0ASince GUIDE applications =
work correctly before changeset 34833:df257404f3e8=0Aand fail afterwards, t=
his appears to be a regression introduced by the changes=0Afor MAT-file han=
dling.=0A=0ANote: Although GUIDE is deprecated, existing GUIDE applications=
 should=0Acontinue to work for backward compatibility.=0A=0ABest regards=0A=
=0A=0A=0A=0A=0A=0A=0A    __________________________________________________=
_____=0A=0AReply to this item at:=0A=0A  <https://savannah.gnu.org/bugs/?68=
594>=0A=0A_______________________________________________=0AMessage sent vi=
a Savannah=0Ahttps://savannah.gnu.org/=0A
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