bug#62572: cp --no-clobber behavior has changed

[Pádraig Brady]

On 01/04/2023 15:46, Alberto Salvia Novella wrote:
> Also there's now a bigger problem: that you cannot tell when the copy
> failed because the file exists, or because any other reason.
>
> People will just use:
> cp --no-clover $in $out || true
>
> But if it fails for any other reason, cross your fingers.
>
> Hence now the option, in practice, is useless. Nobody should be using it.

Well the current thinking is -n is useful to fail with unexpected existing 
files.

For the functionality you want of only updating non existent files,
one should use the proposed --update=none new option.

It's worth mentioning that this being a new option
impacts the portability of scripts that use it.

cheers,
Pádraig