makechrootpkg: sync databases for checkpkg off-site

Use pacman's --dbpath feature to sync fresh databases inside an isolated
location and split up the database sync and package location calls to
remove the need of weird grep calls.

It isn't nice of makechrootpkg to modify the host database state just by
building packages. No foreign program shall automatically modify
the host database other than by the explicit will of a system
maintainer, which is the major reason this changes get incorporated.

However, there is certain indoctrinated believe that using -Sy is
the prime evil. In fact it has been declared as a social rule to a
technical problem of not getting into potential partial upgrade states.
This is not a proper loophole less solution as there are multiple ways
and use cases that lead to such a state, like aborting a -Syu on the
prompt for whatever reason, what really matters is that it is not a
technically bullet proof solution to solve the problem.

Databases shall have the freedom to be as up to date as databases or
their owner wishes, allowing querying on latest database state without
fear. The only loophole-less contract that _really_ is from importance
is always using -Su instead of plain -S to install packages. Installing
packages is what actually brings one into a potential partial upgrade
state and by using -Su an outstanding upgrade is forced when installing
a new package. This properly solves all edge cases in a technical
manner instead of declaring people who abort the prompt of -Syu to be
the problem. In fact, using this simple contract allows whatever system
maintenance workflow a host owner wants to follow, which may still be to
always use -Syu and deal with system upgrades explicitly instead of the
time when installing new packages, but the -Su contract is the real safe
guard to guarantee no edge case can ever slip in. This magically also
opens up the freedom to people who wish to use -Sy to simply query on up
to date data as the currently indoctrinated "never do -Sy" stone plates
not only are not rock solid in technical terms but also make certain use
cases simply impossible and hence cripple the functionality without at
the very least being fully loophole free.

Signed-off-by: Levente Polyak <anthraxx@archlinux.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/makechrootpkg.in b/makechrootpkg.in
index a0a95a7..dfea18c 100644
--- a/makechrootpkg.in
+++ b/makechrootpkg.in
@@ -387,17 +387,28 @@ if (( ret != 0 )); then
 else
 	if (( run_checkpkg )); then
 		msg "Running checkpkg"
-		remotepkgs=($(pacman -Syddp --logfile /dev/null "${pkgnames[@]}"|grep '://'))
+
+		# sync off-site databases for up-to-date queries
+		trap 'rm -rf $dbpath; cleanup' EXIT INT TERM QUIT
+		dbpath=$(mktemp -d --tmpdir makechrootpkg-database.XXXXXXXXXX)
+		mkdir -p "$dbpath"
+		pacman -Sy --dbpath "$dbpath" --logfile /dev/null
+
+		# query current package locations
+		remotepkgs=($(pacman -Sddp --dbpath "$dbpath" --logfile /dev/null "${pkgnames[@]}"))
 		if (( $? )); then
 			warning "Skipped checkpkg due to missing repo packages"
 			exit 0
 		fi
+
+		# download package files if any non-local location exists
 		for remotepkg in "${remotepkgs[@]}"; do
 			[[ $remotepkg == file://* ]] && continue
 			msg2 "Downloading current versions"
-			pacman --noconfirm -Swdd --logfile /dev/null "${pkgnames[@]}"
+			pacman --noconfirm -Swdd --dbpath "$dbpath" --logfile /dev/null "${pkgnames[@]}"
 			break
 		done
+
 		msg2 "Checking packages"
 		sudo -u "$makepkg_user" checkpkg --rmdir --warn
 	fi