This is extremely annoying. I had a large (valid) file, I introduced a few bad values in it, tried to save it. It failed (without error, see larray-project/larray-editor#75) and I then closed the editor to realize my file had disappeared, hence loosing my work!

This happens at least for saving to Excel, but might happen for other backends too.

This is going to be a tad annoying to fix:

if destpath exists:
    if overwrite:
        save file as temppath
        delete destpath
        rename temppath to destpath
    else:
       raise "{despath} already exists"
else:
    save file as destpath

Or, a tad simpler (but at tad less efficient):

save file as temppath
if destpath exists:
    if overwrite:
        delete destpath
    else:
        raise "{despath} already exists"
rename temppath to destpath