owfile: Memory errors

[lanzagar]

Orange version

3.3.8

Expected behavior

Orange shows an error when an operation runs out of memory.
(Might be hard to catch?)

Actual behavior

Orange crashes with error reporting option shown.

Steps to reproduce the behavior

The reported error crashed in apply_edit_domain:
https://github.com/biolab/orange3/blob/master/Orange/widgets/data/owfile.py#L419
But we need to consider other locations with big memory allocations.

Additional info (worksheets, data, screenshots, ...)

[ajdapretnar]

@lanzagar What is the status of this? I know @jerneju has been dealing with memory errors diligently some time ago.

#2521
#2441
#2374
#2397
#2316

But nothing has been done regarding the File widget. Could we sample, just like in SQL? If the file is too big, load only the first n lines and m columns? (column restriction should probably be very loose)

[lanzagar]

I think this was opened as a more general todo item, for us to consider. As it is over a year old, we can probably close this and work on specific problems encountered more recently.