[pacman-dev] [PATCH] makepkg: improve removal of installed dependencies

[Allan McRae]

Compare a list of packages on the system before and after dependency resolution
in order to get a complete list of packages to remove.  This allows makepkg to
remove packages installed due to provides.

Bail in cases where packages that were on the system originally have been
removed as there is a risk of breaking the system when removing the new
packages

Fixes FS#15144

Signed-off-by: Allan McRae <allan at archlinux.org>
---

This moves the generation of the installed package list to directly after
the installation of deps to prevent issues if the user installs packages
while the build is occurring:
http://bugs.archlinux.org/task/15144#comment53938

Rebased on Cedric's run_pacman and $PACMAN patches.

 doc/makepkg.8.txt     |    6 +++---
 scripts/makepkg.sh.in |   39 +++++++++++++++++++++------------------
 2 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/doc/makepkg.8.txt b/doc/makepkg.8.txt
index ad27bca..168b369 100644
--- a/doc/makepkg.8.txt
+++ b/doc/makepkg.8.txt
@@ -166,9 +166,9 @@ Environment Variables
 ---------------------
 *PACMAN*::
 	The command that will be used to check for missing dependencies and to
-	install and remove packages. Pacman's -U, -T, -S and -Rns operations
-	must be supported by this command. If the variable is not set or
-	empty, makepkg will fall back to `pacman'.
+	install and remove packages. Pacman's -Qq, -Rns, -S, -T, and -U
+	operations must be supported by this command. If the variable is not
+	set or empty, makepkg will fall back to `pacman'.
 
 
 Additional Features
diff --git a/scripts/makepkg.sh.in b/scripts/makepkg.sh.in
index c730150..5743ea4 100644
--- a/scripts/makepkg.sh.in
+++ b/scripts/makepkg.sh.in
@@ -27,8 +27,10 @@
 
 # makepkg uses quite a few external programs during its execution. You
 # need to have at least the following installed for makepkg to function:
-#   bsdtar (libarchive), bzip2, coreutils, fakeroot, find (findutils),
-#   getopt (util-linux), gettext, grep, gzip, openssl, sed, tput (ncurses)
+#   bsdtar (libarchive), bzip2, coreutils, diff (diffutils), fakeroot,
+#   find (findutils), getopt (util-linux), gettext, grep, gzip, openssl,
+#   sed, tput (ncurses)
+
 
 # gettext initialization
 export TEXTDOMAIN='pacman'
@@ -343,7 +345,7 @@ download_file() {
 
 run_pacman() {
 	local ret=0
-	if (( ! ASROOT )) && [[ $1 != "-T" ]] && sudo -l $PACMAN &>/dev/null; then
+	if (( ! ASROOT )) && [[ $1 != "-T" && $1 != "-Qq" ]] && sudo -l $PACMAN &>/dev/null; then
 		sudo $PACMAN $PACMAN_OPTS "$@" || ret=$?
 	else
 		$PACMAN $PACMAN_OPTS "$@" || ret=$?
@@ -398,7 +400,6 @@ handle_deps() {
 }
 
 resolve_deps() {
-	# $pkgdeps is a GLOBAL variable, used by remove_deps()
 	local R_DEPS_SATISFIED=0
 	local R_DEPS_MISSING=1
 
@@ -408,7 +409,6 @@ resolve_deps() {
 	fi
 
 	if handle_deps $deplist; then
-		pkgdeps="$pkgdeps $deplist"
 		# check deps again to make sure they were resolved
 		deplist="$(check_deps $*)"
 		[[ -z $deplist ]] && return $R_DEPS_SATISFIED
@@ -425,23 +425,25 @@ resolve_deps() {
 	return $R_DEPS_MISSING
 }
 
-# fix flyspray bug #5923
 remove_deps() {
-	# $pkgdeps is a GLOBAL variable, set by resolve_deps()
 	(( ! RMDEPS )) && return
-	[[ -z $pkgdeps ]] && return
 
-	local dep depstrip deplist
-	deplist=""
-	for dep in $pkgdeps; do
-		depstrip="${dep%%[<=>]*}"
-		deplist="$deplist $depstrip"
-	done
+	# check for packages removed during dependency install (e.g. due to conflicts)
+	# removing all installed packages is risky in this case
+	if (( $(diff <(printf "%s\n" "${original_pkglist[@]}") \
+		<(printf "%s\n" "${current_pkglist[@]}") | grep "<" | wc -l) > 0 )); then
+	  warning "$(gettext "Failed to remove installed dependencies.")"
+	  return 0
+	fi
 
-	msg "Removing installed dependencies..."
+	local deplist=($(diff <(printf "%s\n" "${original_pkglist[@]}") \
+		<(printf "%s\n" "${current_pkglist[@]}") | grep ">"))
+	deplist=(${deplist[@]#>})
+	[ ${#deplist[@]} -eq 0 ] && return
 
+	msg "Removing installed dependencies..."
 	# exit cleanly on failure to remove deps as package has been built successfully
-	if ! run_pacman -Rns $deplist; then
+	if ! run_pacman -Rn ${deplist[@]}; then
 		warning "$(gettext "Failed to remove installed dependencies.")"
 		return 0
 	fi
@@ -1874,14 +1876,13 @@ if (( SOURCEONLY )); then
 	exit 0
 fi
 
-# fix flyspray bug #5973
 if (( NODEPS || NOBUILD || REPKG )); then
 	# no warning message needed for nobuild, repkg
 	if (( NODEPS )); then
 		warning "$(gettext "Skipping dependency checks.")"
 	fi
 elif [ $(type -p "${PACMAN%% *}") ]; then
-	unset pkgdeps # Set by resolve_deps() and used by remove_deps()
+	original_pkglist=($(run_pacman -Qq))    # required by remove_deps
 	deperr=0
 
 	msg "$(gettext "Checking Runtime Dependencies...")"
@@ -1890,6 +1891,8 @@ elif [ $(type -p "${PACMAN%% *}") ]; then
 	msg "$(gettext "Checking Buildtime Dependencies...")"
 	resolve_deps ${makedepends[@]} || deperr=1
 
+	current_pkglist=($(run_pacman -Qq))    # required by remove_deps
+
 	if (( deperr )); then
 		error "$(gettext "Could not resolve all dependencies.")"
 		exit 1
-- 
1.6.5.3