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

[Paul Eggert]

On 2023-03-31 14:32, Pádraig Brady wrote:

> Perhaps we should support:
>    --no-clobber[={skip, fail (default)}]
>
> so then users can at least easily change -n to --no-clobber=skip
> to get the old behavior?
>
> An alternative would be to augment the --update option to support:
>    --update[={none, older (default)}]
> where --update=none would be the equivalent of the old -n behavior.

The latter sounds a bit better but I suppose either would work. We could 
generalize it a bit further, e.g.:

  --skip-diagnose[={yes,no}]
     Whether to diagnose a copying action being skipped.
  --skip-fail[={yes,no}]
     Whether exit status should be 1 when skipping a copying action.

Presumably similar options would apply to ln and mv.

All these extra options might be overkill, though.


> Perhaps we should also diagnose files skipped in the -n fail case,
> to make it easier for users to see what the issue is.

FreeBSD cp -n doesn't diagnose, and GNU cp -n has never diagnosed, so 
it's probably better to leave sleeping dogs lie.