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??? Reference to non-existent field 'matlab'.

Asked by Jordan on 27 Mar 2012

Dear Matlab users,

In Matlab 2009b, when I save a file that is open in the editor, the save executes successfully while the console returns the error:

??? Reference to non-existent field 'matlab'.

This occurs with no execution of code and does not crash any code that is executing, but returns the error once control is returned to the console. Restarting my system or matlab does not clear the issue.

It is more of a nuisance than anything else, but it would be nice to get to the bottom of it. Any ideas?

Cheers, Jordan

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Jordan

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6 Answers

Answer by Jan Simon on 27 Mar 2012

Is this the complete error message? Does:

E = lasterror

reveal the location, which function throws the error?

Does the error appear, if you exclude all user-defined functions from the PATH? If not, one of your functions shadows a function, which is called during saving. It is hard to avoid such problems, because there is no built-in tool to detect such collisions. I've tried to develop such a tool, but the interest in the community is negligible.

1 Comment

Jordan on 27 Mar 2012

Hi Jan,

Thanks for the suggestion - that is a great debugging function that I did not know about. In this case it is not too helpful, though. It returns:

message: 'Reference to non-existent field 'matlab'.'
identifier: 'MATLAB:nonExistentField'
stack: [0x1 struct]

I am trying to track down a possible PATH shadowing problem. I don't get any errors immediately after adding my own paths, but the errors begin after my first crash. I'll post again here if I'm able to track this down...

Jan Simon
Answer by Jan Simon on 27 Mar 2012

If dbstop if error does not stop Matlab, try:

dbstop if all error

1 Comment

Jordan on 28 Mar 2012

Good idea -- but amazingly -- still not catching the error!

Jan Simon
Answer by Matt Tearle on 27 Mar 2012

A shot in the dark, but... your filename isn't something like myfile.matlab.m is it...?

6 Comments

Matt Tearle on 28 Mar 2012

And nothing funky in your path names either, right? (Sorry, don't mean to be a dork, but you mentioned something about it happening after you added directories to your path.)

Daniel on 28 Mar 2012

@Matt, I think the potential for a funky path, or some other corrupted setting, is a likely culprit.

Malcolm Lidierth on 30 Mar 2012

The only accessible reference to MATLAB:nonExistentField seems to be in Tiff.m where the exception is thrown from the MATLAB tifflib code - but that does not help much.

Matt Tearle
Answer by Sean de Wolski on 27 Mar 2012
dbstop if error

Then generate the error and see where it's being called.

4 Comments

Sean de Wolski on 27 Mar 2012

What is your complete workflow? You have a file open in the editor, you save it, you see the error? Is that all? Do you have something shadowing save?

Jordan on 27 Mar 2012

That's right. On further exploration, it seems to start after catching an error with dbstop for the first time. Run program, catch error with dbstop if error, save executed file with changes, see the error.

Strangely, saving files not in the debug function stack only causes errors when NOT in debug mode. That is, if I save a random function file when in the regular console, I get an error. But if I am in debug mode for some unrelated function, no error occurs.

Matt Tearle on 28 Mar 2012

How are you saving? Clicking the Editor save icon, ctrl-S, issuing the save command in Command Window, etc? And out of curiosity, what happens if you issue the following commands instead:

foo = matlab.desktop.editor.getActive
foo.save

Sean de Wolski
Answer by Daniel on 28 Mar 2012

Have you tried deleting/renaming your preferences directory?

0 Comments

Daniel
Answer by Jan Simon on 28 Mar 2012

I guess you have shadowed a Java function, which is required for saving. If the hypothetical function "tool.matlab.editor.save" would be used and you have a variable called "tool", the error message should be similar to your oberservations.

Unfortunately I do not know a function, which contains ".matlab". My trial to ask Google failed, because the dots have been converted automagically to spaces even if I include the term ".matlab." in double quotes and Google CodeSearch is down.

Does whos reveal and suspicious candidates?

3 Comments

Sean de Wolski on 28 Mar 2012

autononmagic!

Daniel on 28 Mar 2012

I am not sure you can overload java functions this way. I created a dummy function java.m and added it to my path and made its directory the current working directory. The call f = java.io.File('MyFile') does not seem to use the overloaded function.

Jan Simon on 29 Mar 2012

I'm not sure also. It is statistical guessing, because unintentionally overloaded functions have been a source of weird problems repeatedly.

Jan Simon

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