[pacman-dev] backup handling ugly mess

[Xavier]

Following the recent bash breakage, Pierre was wondering why the /etc/profile
just stayed there on the filesystem :
http://www.archlinux.org/pipermail/arch-dev-public/2007-December/003556.html

I didn't understand this at all. As stonecrest noted earlier, when the
"current" mirrorlist was removed from pacman package, that file totally
disappeared during the upgrade, even though it was in the old backup array :
http://www.archlinux.org/pipermail/pacman-dev/2007-September/009376.html

This caused the following commit :
http://projects.archlinux.org/git/?p=pacman.git;a=commitdiff;h=843d368ef60a74719dfc74a27de3fe3ef441951f

The first part of this commit is supposed to temporarily add all old backup
entries (besides the new) to the NoUpgrade array. Because of a bug, it
didn't have any effect.

The second part was an idea of me to handle the pacsave during an
removeupgrade just like we already did for a remove, but I finally think
this is a really stupid / misleading / confusing idea. This code shouldn't
even be reached during a removeupgrade if the first part was fixed anyway.

So that was just a little sum up, now description of the bug:
alpm_pkg_get_backup(newpkg) : newpkg is the one that will be installed, so
this only return a list of elements like "file"
alpm_pkg_get_backup(oldpkg) : oldpkg is a locally installed package, so this
return a list of elements like "file<tab>md5sum"

Since the md5sum wasn't removed there, adding these files had 0 effect. Now,
this can easily be fixed. But then all files in either old or new backup
array that were in oldpkg but not in newpkg will just stay there on the
filesystem. They won't be renamed to .pacsave .

Why the bash case was different to the pacman one is that, even if
/etc/profile was removed from the newpkg, it was still in the backup array of
the newpkg (which is the only one pacman looks at). So the file wasn't
removed and was just left on the filesystem.

Even though the bash case is a packaging error, it's a real case that
happened, so it might be worth adding it to the pactests.
-------------- next part --------------
self.description = "Upgrade a package, with a file leaving the pkg but staying in 'backup'"

lp = pmpkg("dummy")
lp.files = ["etc/dummy.conf*"]
lp.backup = ["etc/dummy.conf"]
self.addpkg2db("local", lp)

p = pmpkg("dummy", "1.0-2")
p.backup = ["etc/dummy.conf"]
self.addpkg(p)

self.args = "-U %s" % p.filename()

self.addrule("PKG_VERSION=dummy|1.0-2")
self.addrule("FILE_PACSAVE=etc/dummy.conf")
self.addrule("!FILE_PACNEW=etc/dummy.conf")
self.addrule("FILE_EXIST=etc/dummy.conf")