Rare examples of confusing error messages
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Usually Matlab creates very helpful error messages, e.g.:
??? Subscript indices must either be real positive integers or logicals.
It does not require much experience to identify the source of this error rapidly. (Finding a solution is completely different story!) Compared with e.g. the messages of famous operating systems or the GCC compiler, the high quality of these messages is extremely helpful.
Do you know counter-examples? Some misleading or irrelevant messages created by Matlab?
3 Comments
James Muchechetere
on 23 Aug 2019
Yes. Got this message in r2017a:
Error using CPFSKModulator/parenReference
When the BitInput property is set to true, inputs must have be double or logical.
Accepted Answer
Andreas Goser
on 24 Apr 2012
My all-time favourite is
Caught unexpected exception of unknown type.
7 Comments
Walter Roberson
on 4 May 2019
I think that solution migrated to https://www.mathworks.com/matlabcentral/answers/99628-why-do-i-receive-an-assertion-when-i-specify-the-property-xdatasource-in-plot
Walter Roberson
on 4 May 2019
Edited: Walter Roberson
on 4 May 2019
It appears there is also the cause at https://www.mathworks.com/matlabcentral/answers/224739-matlab-r2015a-startup-error-regarding-java-lang-runtimeexception which related to Java and temporary directories and loading libraries.
There may also be causes related to loadlib() or possiby TCP; https://www.mathworks.com/matlabcentral/answers/142270-caught-unexpected-exception-of-unknown-type-tcp-ip-device-connection
More Answers (8)
Daniel Shub
on 23 Apr 2012
Definitely on the irrelevant side, but luckily it was taken care of pretty quickly. I think it might be the first bug I reported to TMW.
Basically someone at TMW left a debugging message in the serial port object callback so that it would always rethrow the last warning.
Oleg Komarov
on 23 Apr 2012
The guilty one:
foo('')
Undefined function 'foo' for input arguments of type 'char'.
No inputs:
foo
Undefined function or variable 'foo'.
Use as variable OR function?
clear foo
sum(foo)
Undefined function or variable 'foo'.
The two error messages considered together make you think that the first one is simply not properly behaving BECAUSE of the input.
However, most commonly it's the case of "undefined function" which is already implemented!
I suggest to suppress the first one and throw always the second message.
5 Comments
Image Analyst
on 24 Apr 2012
Seems to me it should look it up by function name (m-filename). So it should look for foo.m, not all possible functions of any name that take a class char (which would be a lot) and then determine if any of them are named foo.
Daniel Shub
on 23 Apr 2012
Another unhelpful aspect of error handling in MATLAB is if you catch an error in a callback and then rethrow the error, you lose the stack information.
0 Comments
Walter Roberson
on 26 Apr 2012
Invoke Error, Dispatch Exception: Exception Error Occurred
isn't the most enlightening of messages...
0 Comments
Adam
on 17 Jan 2017
was one I got the other day. Not sure what I had done to get it though! I especially like the one word per line formatting!
2 Comments
Steven Lord
on 17 Jan 2017
I searched a little bit and I'm not sure that's from a MathWorks function. [It is being displayed in a msgbox with the 'error' Icon, I believe, but that's a function anyone can call.]
Adam
on 18 Jan 2017
It's definitely something deep down as I got it again yesterday when I tried to open a file that I had moved and was actually not on my path any more. I hit Ctrl C or pause or something and ended up with that message. It isn't something in my own code or 3rd party code that I have though so not sure what its source is!
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