diffpkg: support comparing two given package archives

This adds support similar to diffpkg from the infrastructure repo
that is based on the assumption that two archives can be passed
to the tooling in order to compare them.

diffpkg.in

@@ -8,12 +8,19 @@ m4_include(lib/common.sh)
 
 usage() {
     cat <<- _EOF_
-		Usage: ${BASH_SOURCE[0]##*/} [OPTIONS] [MODES]
+		Usage: ${BASH_SOURCE[0]##*/} [OPTIONS] [MODES] [FILE|PKGNAME...]
 
 		Searches for a locally built package corresponding to the PKGBUILD, and
 		downloads the last version of that package from the Pacman repositories.
-		It then compares them using different modes while using simple tar
+		It then compares the package archives using different modes while using
-		content list by default.
+		simple tar content list by default.
+
+		When given one package, use it to diff against the locally built one.
+		When given two packages, diff both packages against each other.
+
+		In either case, a package name will be converted to a filename from the
+		cache, and diffpkg will proceed as though this filename was initially
+		specified.
 
 		OPTIONS
 		    -M, --makepkg-config Set an alternate makepkg configuration file
@@ -100,19 +107,10 @@ elif [[ -r "$HOME/.makepkg.conf" ]]; then
 	source "$HOME/.makepkg.conf"
 fi
 
-if [[ ! -f PKGBUILD ]]; then
-	die 'This must be run in the directory of a built package.'
-fi
-
-# shellcheck source=PKGBUILD.proto
-. ./PKGBUILD
-if [[ ${arch[0]} == 'any' ]]; then
-	CARCH='any'
-fi
-
 STARTDIR=$(pwd)
-trap 'rm -rf $TEMPDIR' EXIT INT TERM QUIT
+trap 'rm -rf $TMPDIR' EXIT INT TERM QUIT
-TEMPDIR=$(mktemp -d --tmpdir diffpkg-script.XXXXXXXX)
+TMPDIR=$(mktemp -d --tmpdir diffpkg-script.XXXXXXXX)
+export TMPDIR
 
 tar_list() {
 	bsdtar tf "$*" | if (( VERBOSE )); then
@@ -123,78 +121,108 @@ tar_list() {
 }
 
 diff_pkgs() {
-	local oldpkg=$1
+	local oldpkg newpkg
-	local newpkg=$2
+	oldpkg=$(readlink -m "$1")
+	newpkg=$(readlink -m "$2")
+
+	[[ -f $oldpkg ]] || die "No such file: %s" "${oldpkg}"
+	[[ -f $newpkg ]] || die "No such file: %s" "${newpkg}"
 
 	if (( TARLIST )); then
-		tar_list "$oldpkg" > "$TEMPDIR/filelist-old"
+		tar_list "$oldpkg" > "$TMPDIR/filelist-old"
-		tar_list "$newpkg" > "$TEMPDIR/filelist"
+		tar_list "$newpkg" > "$TMPDIR/filelist"
 
-		sdiff -s "$TEMPDIR/filelist-old" "$TEMPDIR/filelist"
+		sdiff -s "$TMPDIR/filelist-old" "$TMPDIR/filelist"
 	fi
 
 	if (( PKGINFO )); then
-		bsdtar xOqf "$oldpkg" .PKGINFO > "$TEMPDIR/pkginfo-old"
+		bsdtar xOqf "$oldpkg" .PKGINFO > "$TMPDIR/pkginfo-old"
-		bsdtar xOqf "$newpkg" .PKGINFO > "$TEMPDIR/pkginfo"
+		bsdtar xOqf "$newpkg" .PKGINFO > "$TMPDIR/pkginfo"
 
-		sdiff -s "$TEMPDIR/pkginfo-old" "$TEMPDIR/pkginfo"
+		sdiff -s "$TMPDIR/pkginfo-old" "$TMPDIR/pkginfo"
 	fi
 
 	if (( BUILDINFO )); then
-		bsdtar xOqf "$oldpkg" .BUILDINFO > "$TEMPDIR/buildinfo-old"
+		bsdtar xOqf "$oldpkg" .BUILDINFO > "$TMPDIR/buildinfo-old"
-		bsdtar xOqf "$newpkg" .BUILDINFO > "$TEMPDIR/buildinfo"
+		bsdtar xOqf "$newpkg" .BUILDINFO > "$TMPDIR/buildinfo"
 
-		sdiff -s "$TEMPDIR/buildinfo-old" "$TEMPDIR/buildinfo"
+		sdiff -s "$TMPDIR/buildinfo-old" "$TMPDIR/buildinfo"
 	fi
 
 	if (( DIFFOSCOPE )); then
-		diffoscope "$(readlink -e "$oldpkg")" "$(readlink -e "$newpkg")"
+		diffoscope "$oldpkg" "$newpkg"
 	fi
 }
 
-for _pkgname in "${pkgname[@]}"; do
+fetch_pkg() {
-	comparepkg=$_pkgname
+	local pkg pkgdest pkgurl
-	pkgurl=
+	case $1 in
-	target_pkgver=$(get_full_version "$_pkgname")
+		*://*)
-	if ! pkgfile=$(find_cached_package "$_pkgname" "$target_pkgver" "$CARCH"); then
+			pkgurl=$1 ;;
-		die 'tarball not found for package: %s' "${_pkgname}-$target_pkgver"
+		/*|*/*)
-	fi
+			pkgurl=$(readlink -m "$1") ;;
+		*.pkg.tar*)
+			pkgurl=$1 ;;
+		'')
+			;;
+		*)
+			pkg=$1 ;;
+	esac
 
-	ln -s "$pkgfile" "$TEMPDIR"
+	[[ -n $pkgurl ]] || pkgurl=$(pacman -Spdd --print-format '%l' --noconfirm "$pkg") ||
+		die "Couldn't download previous package for %s." "$pkg"
 
-	if (( $# )); then
+	pkg=${pkgurl##*/}
-		case $1 in
+	pkgdest=$(mktemp -t -d "${pkg}-XXXXXX")/${pkg}
-			*://*)
-				pkgurl=$1 ;;
-			/*|*/*)
-				pkgurl=$(readlink -m "$1") ;;
-			*.pkg.tar*)
-				pkgurl=$1 ;;
-			'')
-				;;
-			*)
-				comparepkg=$1 ;;
-		esac
-		shift
-	fi
-	[[ -n $pkgurl ]] || pkgurl=$(pacman -Spdd --print-format '%l' --noconfirm "$comparepkg") ||
-		die "Couldn't download previous package for %s." "$comparepkg"
-
-	oldpkg=${pkgurl##*/}
-
-	if [[ ${oldpkg} = "${pkgfile##*/}" ]]; then
-		die "The built package (%s) is the one in the repo right now!" "$_pkgname"
-	fi
 
 	if [[ $pkgurl = file://* || ( $pkgurl = /* && -f $pkgurl ) ]]; then
-		ln -s "${pkgurl#file://}" "$TEMPDIR/$oldpkg"
+		ln -sf "${pkgurl#file://}" "$pkgdest"
-	elif [[ -f "$PKGDEST/$oldpkg" ]]; then
+	elif [[ -f "$PKGDEST/$pkg" ]]; then
-		ln -s "$PKGDEST/$oldpkg" "$TEMPDIR/$oldpkg"
+		ln -sf "$PKGDEST/$pkg" "$pkgdest"
-	elif [[ -f "$STARTDIR/$oldpkg" ]]; then
+	elif [[ -f "$STARTDIR/$pkg" ]]; then
-		ln -s "$STARTDIR/$oldpkg" "$TEMPDIR/$oldpkg"
+		ln -sf "$STARTDIR/$pkg" "$pkgdest"
+	elif [[ $pkgurl = *://* ]]; then
+		curl -fsLC - --retry 3 --retry-delay 3 -o "$pkgdest" "$pkgurl" || \
+			die "Couldn't download %s" "$pkgurl"
 	else
-		curl -fsLC - --retry 3 --retry-delay 3 -o "$TEMPDIR/$oldpkg" "$pkgurl"
+		die "File not found: %s" "$pkgurl"
 	fi
 
-	diff_pkgs "$TEMPDIR/$oldpkg" "$pkgfile"
+	echo "$pkgdest"
-done
+}
+
+if (( $# < 2 )); then
+	if [[ ! -f PKGBUILD ]]; then
+		die "This must be run in the directory of a built package.\nTry '$(basename "$0") --help' for more information."
+	fi
+
+	# shellcheck source=PKGBUILD.proto
+	. ./PKGBUILD
+	if [[ ${arch[0]} == 'any' ]]; then
+		CARCH='any'
+	fi
+
+	for _pkgname in "${pkgname[@]}"; do
+		comparepkg=$_pkgname
+		pkgurl=
+		target_pkgver=$(get_full_version "$_pkgname")
+		if ! pkgfile=$(find_cached_package "$_pkgname" "$target_pkgver" "$CARCH"); then
+			die 'tarball not found for package: %s' "${_pkgname}-$target_pkgver"
+		fi
+
+		ln -s "$pkgfile" "$TMPDIR"
+
+		if (( $# )); then
+			comparepkg="$1"
+		fi
+
+		oldpkg=$(fetch_pkg "$comparepkg") || exit 1
+
+		diff_pkgs "$oldpkg" "$pkgfile"
+	done
+else
+	file1=$(fetch_pkg "$1") || exit 1
+	file2=$(fetch_pkg "$2") || exit 1
+
+	diff_pkgs "$file1" "$file2"
+fi

doc/diffpkg.1.asciidoc

@@ -7,15 +7,22 @@ diffpkg - Compare package files using different modes.
 
 Synopsis
 --------
-diffpkg [OPTIONS] [MODES]
+diffpkg [OPTIONS] [MODES] [FILE|PKGNAME...]
 
 Description
 -----------
 
 Searches for a locally built package corresponding to the PKGBUILD, and
 downloads the last version of that package from the Pacman repositories.
-It then compares them using different modes while using simple tar
+It then compares the package archives using different modes while using
-content list by default.
+simple tar content list by default.
+
+When given one package, use it to diff against the locally built one.
+When given two packages, diff both packages against each other.
+
+In either case, a package name will be converted to a filename from the
+cache, and diffpkg will proceed as though this filename was initially
+specified.
 
 Options
 -------

zsh_completion.in

@@ -49,6 +49,7 @@ _diffpkg_args=(
 	'(-m --makepkg-config)'{-m,--makepkg-config}'[Location of a makepkg config file]:makepkg_config:_files -g "*.conf(.)"'
 	'(-v --verbose)'{-v,--verbose}'[Provide more detailed/unfiltered output]'
 	'(-h --help)'{-h,--help}'[Display usage]'
+	'*:packages:_devtools_completions_all_packages'
 )
 
 _finddeps_args=(