[pacman-dev] [PATCH] Handle removal of empty directories properly

[Xavier Chantry]

On Sat, Jul 16, 2011 at 5:11 PM, Dan McGee <dan at archlinux.org> wrote:
> This addresses FS#25141. We shouldn't remove every empty directory we
> come across during the removal process unless it is truly not known to
> any other package. This will prevent removal of essential directories
> such as '/var/lock/'.
>
> This is accomplished by first checking the empty/non-empty status of a
> directory, which was previously done implicitly by calling rmdir() and
> ignoring errors. We do this to avoid the next (new) check in most cases,
> which is to look at all local packages to see if the to-be-removed
> directory is present in another packages' filelist. If we do not find it
> anywhere, then we remove it, else we keep the file around.
>

I always thought pacman should do that, but Nagy concerns were
obviously right, loading /var/lib/pacman/local/*/files takes time.
This just highlights once more the poor design of the local db.

pacman -R teeworlds goes from 2sec to 12sec here (after dropping caches)

... and from 0.4sec to 0.7sec when everything is cached. But only a
pacman -Qo 'orphaned_file' or a previous -R operation would load all
/var/lib/pacman/local/*/files

Just to make myself clear, I think this patch should go in, and the
local db out :)
In the meantime, we have filesystem loops fortunately.