bug#13601: mv should not silently lose file extended attributes

On 16/08/2026 05:27, Collin Funk wrote:
> Paul Eggert <[email protected]> writes:
> 
>> Since mv ordinarily acts like 'cp --preserve=all' when copying, presumably mv should warn in this situation if cp warns.
>>
>> Also, if no mv options other than -i and -f are used, a diagnostic is
>> needed to conform to the spirit of POSIX, as the POSIX spec says for
>> this situation "If the duplication of the file characteristics fails
>> for any reason, mv shall write a diagnostic message to standard error,
>> but this failure shall not cause mv to modify its exit status."[1]
>> Contrary to the original bug report POSIX does not require (and
>> seemingly does not allow) the mv to be aborted if file characteristics
>> are lost in the copy, but at least the user should be warned about the
>> situation.
> 
> Thanks for the link. POSIX seems pretty clear here.
> 
> The attached patch should fix things. I was tempted to add another
> option to "struct cp_options", but it was more unwieldy then just
> setting "require_preserve_xattr" and special casing "move_mode" to not
> change the exit status.

The logic looks sound.

We might get complaints for the extra warnings,
but I suppose users can `cp -a && rm` for more granular warning support.


> It would be nice to add a test but it seems strace can't inject
> ENOTSUP. I'll see if I can think of an alternative.

EOPNOTSUPP works
Another option is to perhaps augment tests/cp/cp-mv-enotsup-xattr.sh

BTW it would be good to reference https://bugs.gnu.org/13601
in the commit message.

thanks!
Padraig