libmakepkg: add lint_config to validate SRCEXT/PKGEXT

These variables must begin with .src.tar / .pkg.tar respectively, so
fail early if those expectations are not matched. This prevents makepkg
from creating e.g. package files literally named "./pacman-5.1.3-1-x86_64"
which are actually uncompressed tarballs.

Signed-off-by: Eli Schwartz <eschwartz@archlinux.org>
Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/Makefile.am

@@ -72,6 +72,7 @@ LIBMAKEPKG_IN = \
 	libmakepkg/integrity/verify_checksum.sh \
 	libmakepkg/integrity/verify_signature.sh \
 	libmakepkg/lint_config.sh \
+	libmakepkg/lint_config/ext.sh \
 	libmakepkg/lint_config/paths.sh \
 	libmakepkg/lint_config/source_date_epoch.sh \
 	libmakepkg/lint_config/variable.sh \

scripts/libmakepkg/lint_config/ext.sh.in

@@ -0,0 +1,45 @@
+#!/bin/bash
+#
+#   ext.sh - Check that source/package extensions have valid prefixes
+#
+#   Copyright (c) 2019 Pacman Development Team <pacman-dev@archlinux.org>
+#
+#   This program is free software; you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation; either version 2 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+[[ -n "$LIBMAKEPKG_LINT_CONFIG_EXT_SH" ]] && return
+LIBMAKEPKG_LINT_CONFIG_EXT_SH=1
+
+LIBRARY=${LIBRARY:-'@libmakepkgdir@'}
+
+source "$LIBRARY/util/message.sh"
+
+lint_config_functions+=('lint_ext')
+
+
+lint_ext() {
+	local i var val ret=0
+
+	for i in 'SRCEXT/.src.tar' 'PKGEXT/.pkg.tar';  do
+		IFS='/' read -r var val < <(printf '%s\n' "$i")
+
+		if [[ ${!var} != ${val}* ]]; then
+			error "$(gettext "%s does not contain a valid package suffix (needs '%s', got '%s')")" \
+				"\$${var}" "${val}*" "${!var}"
+			ret=1
+		fi
+	done
+
+	return $ret
+}

scripts/libmakepkg/lint_config/meson.build

@@ -1,6 +1,7 @@
 libmakepkg_module = 'lint_config'
 
 sources = [
+  'ext.sh.in',
   'paths.sh.in',
   'source_date_epoch.sh.in',
   'variable.sh.in',