bugGNU Octave - Bugs: bug #65214, Evaluation of properties...


bug #65214: Evaluation of properties referencing other properties fails

Submitter:  None
Submitted:  Fri 26 Jan 2024 07:58:36 AM UTC
Category:  Classdef Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Unexpected Error or Warning
Status:  Duplicate Assigned to:  jwe
Originator Name:  Alexander Entinger Originator Email:  -email is unavailable-
Open/Closed:  * Open Release:  * dev
Operating System:  * GNU/Linux Fixed Release:  None
Planned Release:  None
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Fri 26 Jan 2024 04:57:55 PM UTC, comment #4: 

Added dependency on bug #52582 of which this bug report is essentially a duplicate.  However, no problem to solve it here and then close both of them.

Attached is code from previous bug report.

# Constant property which is dervied from an expression, rather than a
# fixed value, doesn't parse and emits error.
classdef cdef_const_crash
  properties( Constant = true )
    FOO = 2;
    BAR = 4;
    FOOBAR = cdef_const_crash.FOO * cdef_const_crash.BAR;


c = cdef_const_crash
error: no such file, '/home/rik/wip/Projects_Mine/octave-dev/cdef_const_crash.m'
error: called from

(file #55616)

Rik <rik5>
Group administrator
Fri 26 Jan 2024 03:39:09 PM UTC, comment #3: 

OK, thanks for checking.  Fixing this will require a bit more work then.  I'll try to take another look at it.

John W. Eaton <jwe>
Group administrator
Fri 26 Jan 2024 03:36:12 PM UTC, comment #2: 

using matlab 2023b, the original class with MinBug.A works. :

>> obj = MinBug()

obj =

  MinBug with properties:

    A: 1
    B: 2

if i change the

 B = MinBug.A * 2

line to

 B = A * 2

i get an error:

>> obj = MinBug()
Invalid default value for property 'B' in class 'MinBug':
Unrecognized function or variable 'A'.

Nicholas Jankowski <nrjank>
Group Member
Fri 26 Jan 2024 03:22:03 PM UTC, comment #1: 

I'm attaching a copy of my proposed patch, updated with the bug number.

Does the syntax

    B = MinBug.A * 2

work in Matlab?  That won't work in Octave, even with my change.  But with the change, you can use

    B = A * 2

If the CLASSNAME.PROPERTY syntax is supposed to work, then the fix for that is probably similar to the one required for the problem mentioned in this FIXME note in cdef-class.cc:

      // FIXME: default property expression should be able to call static
      //        methods of the class being constructed.  A restricted
      //        CLASSNAME symbol should be added to the scope before
      //        evaluating default value expressions.

(file #55615)

John W. Eaton <jwe>
Group administrator
Fri 26 Jan 2024 07:58:36 AM UTC, original submission:  

Full discussion see here: https://octave.discourse.group/t/how-to-reference-a-const-property-within-an-octave-class/5214

I’m experiencing a problem when I want to reference a constant property member of a class from another property of the very same class. The minimal Octave code showing this problem is this:

classdef MinBug
  properties (Constant = true)
    A = 1
    B = MinBug.A * 2

When trying to instantiate a new object via obj = MinBug() this error occurs:

error: no such file, 'PATH_TO_MINBUG/MinBug.m'
error: called from



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Attach Files:

Attached Files
file #55616:  cdef_const_crash.m added by rik5 (270B - text/x-objcsrc)
file #55615:  classdef-prop-init.txt added by jwe (4KiB - text/plain)


   bug dependencies.

Items that depend on this one: None found


Carbon-Copy List
  • -email is unavailable- added by rik5 (Updated the item)
  • -email is unavailable- added by nrjank (Posted a comment)
  • -email is unavailable- added by jwe (Updated the item)
  • -email is unavailable- added by None (Submitted the item)

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    Follow 5 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2024-01-26 rik5 Attached File- Added cdef_const_crash.m, #55616
        StatusNone Duplicate
        Assigned toNone jwe
        Dependencies- Depends on bugs #52582
    2024-01-26 jwe Attached File- Added classdef-prop-init.txt, #55615

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