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

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

Answer 1

[Jan]

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.

[Jordan]

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...

Answer 2

[Jan]

If dbstop if error does not stop Matlab, try:

dbstop if all error

[Jordan]

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

Answer 3

[Matt Tearle]

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

[Jordan]

Thanks for the suggestion, but no -- I am only working with regular 'function.m' files.

[Image Analyst]

Well how long is this file? Is it too long to simply paste here so people can stop guessing and see your code?

[Jordan]

Analyst: I don't think posting code would help as the issue is not limited to any one function. For example, I created the function

function imafunction

a=1

return

...and I get the same error when I save the file, though that function does save and execute.

[Matt Tearle]

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 Shub]

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

[Malcolm Lidierth]

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.

Answer 4

[Sean de Wolski]

dbstop if error

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

[Jordan]

This works in my normal debugging but strangely, doesn't catch this particular error.

[Sean de Wolski]

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]

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]

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

Answer 5

[Daniel Shub]

Have you tried deleting/renaming your preferences directory?

Answer 6

[Jan]

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?

[Sean de Wolski]

autononmagic!

[Daniel Shub]

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]

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

Answer 7

[Andrew Meintz]

I had the same issue and when I clean the build folder from previous generated file. It works.