Re: Revisiting "file changed as we read it", with a proposed patch

[Paul Eggert]

On 6/3/22 14:47, Piotr P. Stefaniak wrote:
> And in principle it would have been the desired behavior if I got to say
> what it means for a file to change. In my particular case, it's safe and
> preferable to ignore situations where ctime changes (permission update,
> hardlink count change, etc.) but mtime does not. But I do want to learn
> when mtime changes because that's a bug in the database and I ought to
> report it.

On further thought, I think the flexibility you're suggesting isn't 
needed because pretty much everybody is in your situation, in that users 
don't care about ctime and so don't mind if it changes. Users care 
whether changes to the file mean that the tarball doesn't correspond to 
any state that the file ever had. For this, ctime is a false alarm for 
the reasons you mentioned (adding a hard link).

With that in mind I installed the attached patch into GNU tar's master 
branch on Savannah. I think this addresses the issue you mentioned, 
because the patched GNU tar won't warn at all in that situation. This 
also fixes some other issues that I noticed while in the neighborhood 
(see the NEWS file and the commit message).

Comments welcome.

0001-Warn-file-changed-as-we-read-it-less-often.patch
Description: Text Data