makepkg: move config loading into libmakepkg

When scripting/automating around makepkg, it is sometimes desirable to
know how makepkg will be configured to operate. One example is the
archlinux devtools, which must forward select makepkg.conf variables
into a build chroot (for example PACKAGER) or use those variables itself
(for example {SRC,PKG,LOG}DEST).

The configuration file can be in up to 3 places, and should be capable
of being overridden via environment variables. It is sufficiently
complex to represent distinct functionality, and sufficiently useful to
merit easy accessibility in other scripts, therefore, let us move it
into a publicly exposed utility library.

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

scripts/Makefile.am

@@ -124,6 +124,7 @@ LIBMAKEPKG_IN = \
 	libmakepkg/tidy/zipman.sh \
 	libmakepkg/util.sh \
 	libmakepkg/util/compress.sh \
+	libmakepkg/util/config.sh \
 	libmakepkg/util/error.sh \
 	libmakepkg/util/message.sh \
 	libmakepkg/util/option.sh \

scripts/libmakepkg/util/config.sh.in

@@ -0,0 +1,56 @@
+#!/bin/bash
+#
+#   config.sh - functions for handling makepkg config files
+#
+#   Copyright (c) 2006-2019 Pacman Development Team <pacman-dev@archlinux.org>
+#   Copyright (c) 2002-2006 by Judd Vinet <jvinet@zeroflux.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 "$LIBMAKEPKG_UTIL_CONFIG_SH" ]] && return
+LIBMAKEPKG_UTIL_CONFIG_SH=1
+
+LIBRARY=${LIBRARY:-'@libmakepkgdir@'}
+
+source "$LIBRARY/util/error.sh"
+source "$LIBRARY/util/message.sh"
+source "$LIBRARY/util/util.sh"
+
+# correctly source makepkg.conf, respecting user precedence and the system conf
+source_makepkg_config() {
+	# $1: override system config file
+
+	local MAKEPKG_CONF=${1:-${MAKEPKG_CONF:-@sysconfdir@/makepkg.conf}}
+
+	# Source the config file; fail if it is not found
+	if [[ -r $MAKEPKG_CONF ]]; then
+		source_safe "$MAKEPKG_CONF"
+	else
+		error "$(gettext "%s not found.")" "$MAKEPKG_CONF"
+		plain "$(gettext "Aborting...")"
+		exit $E_CONFIG_ERROR
+	fi
+
+	# Source user-specific makepkg.conf overrides, but only if no override config
+	# file was specified
+	XDG_PACMAN_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/pacman"
+	if [[ $MAKEPKG_CONF = "@sysconfdir@/makepkg.conf" ]]; then
+		if [[ -r $XDG_PACMAN_DIR/makepkg.conf ]]; then
+			source_safe "$XDG_PACMAN_DIR/makepkg.conf"
+		elif [[ -r $HOME/.makepkg.conf ]]; then
+			source_safe "$HOME/.makepkg.conf"
+		fi
+	fi
+}

scripts/libmakepkg/util/meson.build

@@ -2,6 +2,7 @@ libmakepkg_module = 'util'
 
 sources = [
   'compress.sh.in',
+  'config.sh.in',
   'error.sh.in',
   'message.sh.in',
   'option.sh.in',

scripts/libmakepkg/util/util.sh.in

@@ -24,6 +24,7 @@ LIBMAKEPKG_UTIL_UTIL_SH=1
 
 LIBRARY=${LIBRARY:-'@libmakepkgdir@'}
 
+source "$LIBRARY/util/error.sh"
 source "$LIBRARY/util/message.sh"
 
 ##
@@ -98,3 +99,16 @@ ensure_writable_dir() {
 
 	return 0
 }
+
+# source a file and fail if it does not succeed
+source_safe() {
+	local shellopts=$(shopt -p extglob)
+	shopt -u extglob
+
+	if ! source "$@"; then
+		error "$(gettext "Failed to source %s")" "$1"
+		exit $E_MISSING_FILE
+	fi
+
+	eval "$shellopts"
+}

scripts/makepkg.sh.in

@@ -354,15 +354,6 @@ error_function() {
 	exit $E_USER_FUNCTION_FAILED
 }
 
-source_safe() {
-	shopt -u extglob
-	if ! source "$@"; then
-		error "$(gettext "Failed to source %s")" "$1"
-		exit $E_MISSING_FILE
-	fi
-	shopt -s extglob
-}
-
 merge_arch_attrs() {
 	local attr supported_attrs=(
 		provides conflicts depends replaces optdepends
@@ -1112,28 +1103,7 @@ trap 'trap_exit USR1 "$(gettext "An unknown error has occurred. Exiting...")"' E
 # preserve environment variables to override makepkg.conf
 restore_envvars=$(declare -p PKGDEST SRCDEST SRCPKGDEST LOGDEST BUILDDIR PKGEXT SRCEXT GPGKEY PACKAGER CARCH 2>/dev/null || true)
 
-# default config is makepkg.conf
-MAKEPKG_CONF=${MAKEPKG_CONF:-$confdir/makepkg.conf}
-
-# Source the config file; fail if it is not found
-if [[ -r $MAKEPKG_CONF ]]; then
-	source_safe "$MAKEPKG_CONF"
-else
-	error "$(gettext "%s not found.")" "$MAKEPKG_CONF"
-	plain "$(gettext "Aborting...")"
-	exit $E_CONFIG_ERROR
-fi
-
-# Source user-specific makepkg.conf overrides, but only if no override config
-# file was specified
-XDG_PACMAN_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/pacman"
-if [[ "$MAKEPKG_CONF" = "$confdir/makepkg.conf" ]]; then
-	if [[ -r "$XDG_PACMAN_DIR/makepkg.conf" ]]; then
-		source_safe "$XDG_PACMAN_DIR/makepkg.conf"
-	elif [[ -r "$HOME/.makepkg.conf" ]]; then
-		source_safe "$HOME/.makepkg.conf"
-	fi
-fi
+source_makepkg_config
 
 eval "$restore_envvars"