Subject: bug#78638: 30.1; When editing a remote file owned by another user, Tramp signals an error because it cannot change the file mode

From: Michael Albinus <[email-masked]>
Date: Sat, 14 Jun 2025 16:01:56 +0200

Eli Zaretskii <[email-masked]> writes:

Hi Eli,

>> >> Likely, this is due to missing permissions in the upper directory.
>> >
>> > If the permission of the parent directory are the problem, then the
>> > same problem could happen with local files, right?
>>
>> Likely, I am wrong. As Andreas Schwab wrote, to be able to chmod a file
>> you need to be owner (or privileged), other permissions are not
>> relevant.
>
> Again, this can happen with local files as well.  And AFAIU
> backup-by-copying should have handled that situation.

I've reproduced the problem with local files, no Tramp involved. It
happens also, both with setting backup-by-copying to nil or t.

Best regards, Michael.