Sync from Emacs overlay: Make elisp-emacs-version() more robust.

1 files changed, 16 insertions, 4 deletions

diff --git a/eclass/elisp-common.eclass b/eclass/elisp-common.eclass
index 466818e47f9e..fe1305fdd9e6 100644
--- a/eclass/elisp-common.eclass
+++ b/eclass/elisp-common.eclass
@@ -1,6 +1,6 @@
 # Copyright 1999-2013 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
-# $Header: /var/cvsroot/gentoo-x86/eclass/elisp-common.eclass,v 1.84 2013/03/16 08:55:30 ulm Exp $
+# $Header: /var/cvsroot/gentoo-x86/eclass/elisp-common.eclass,v 1.85 2013/08/02 16:48:18 ulm Exp $
 #
 # @ECLASS: elisp-common.eclass
 # @MAINTAINER:
@@ -173,16 +173,28 @@ BYTECOMPFLAGS="-L ."
 # Output version of currently active Emacs.
 
 elisp-emacs-version() {
-	local ret
+	local version ret
 	# The following will work for at least versions 18-24.
 	echo "(princ emacs-version)" >"${T}"/emacs-version.el
-	${EMACS} ${EMACSFLAGS} -l "${T}"/emacs-version.el
+	version=$(
+		# EMACS could be a microemacs variant that ignores the -batch
+		# option and would therefore hang, waiting for user interaction.
+		# Redirecting stdin and unsetting TERM and DISPLAY will cause
+		# most of them to exit with an error.
+		unset TERM DISPLAY
+		${EMACS} ${EMACSFLAGS} -l "${T}"/emacs-version.el </dev/null
+	)
 	ret=$?
 	rm -f "${T}"/emacs-version.el
 	if [[ ${ret} -ne 0 ]]; then
 		eerror "elisp-emacs-version: Failed to run ${EMACS}"
+		return ${ret}
+	fi
+	if [[ -z ${version} ]]; then
+		eerror "elisp-emacs-version: Could not determine Emacs version"
+		return 1
 	fi
-	return ${ret}
+	echo "${version}"
 }
 
 # @FUNCTION: elisp-need-emacs