splitapply does not retain ME stack

When the function that splitapply throws an error, this line number of this error is not include in the output (matlab2024b)

Example:

T=table([1:3]');
G=findgroups(T);
splitapply(@fun, T, G);
function out = fun(varargin)
ERROR
end

This returns:

Error using splitapply>localsplitandapply (line 196)
Unable to apply the function 'fun' to the 1st group of data.

Error in splitapply (line 135)
varargout = localsplitandapply(fun,dataVars,gdiffed,sgnums,gdim,nargout);

Error in templateLoopOverAll (line 231)
splitapply(@fun, T, G);

Caused by:
    Unrecognized function or variable 'ERROR'.

I was expeting that the line number that actually caused that error would be included:

    Error in testfile>fun (line 5)
    ERROR
    
    Error in testfile (line 3)
    fun()

Missing this information makes the debugging of fun very challenging.

How to retrieve this line number?

[Vasco]

I think that this data is removed in splitapply.m line 243.

Answer 1

[Matt J]

Run with Pause on Errors.

Then the code will stop at the offending line:

[Matt J]

Youc an also invoke Pause on Errors from the command line with,

>> dbstop if error

[Vasco]

dbstop if caught error

That works!

From the menu it does not work:

• This does not work on my installation, it stops at splitapply.m line 196
• That seems not to work when I press: run this section (crtl-enter) -> it does not stop at al

[Walter Roberson]

Try

dbstop if caught error

[Matt J]

dbstop if error should be sufficient in R2024b when the script is run in full. My demo above used that.

The other observations are intended behavior.